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  • 1.
    Andersson, Sofia
    et al.
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Dalhammar, Gunnel
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Influence of microbial interactions and EPS/polysaccharide composition on nutrient removal activity in biofilms formed by strains found in wastewater treatment systems2011In: Microbiology Research, ISSN 0944-5013, E-ISSN 1618-0623, Vol. 166, no 6, p. 449-457Article in journal (Refereed)
    Abstract [en]

    The study of biofilm function, structure and microbial interactions might help to improve our understanding of biofilm wastewater treatment processes. However, few reports specifically address the influence of interactions within multispecies biofilms on microbial activity and biofilm composition. Thus, the relationship between biofilm formation, denitrification activity, phosphorus removal and the composition of extracellular polymeric substances (EPS), exopolysaccharides and the bacterial community was investigated using biofilms of denitrifying and phosphorus removing strains Comamonas denitrificans 110, Brachymonas denitrificans B79, Aeromonas hydrophila L6 and Acinetobacter calcoaceticus ATCC23055. Denitrification activity within the biofilms generally increased with the amount of biofilm while phosphorus removal depended on bacterial growth rate. Synergistic effects of co-growth on denitrification (B. denitrificans B79 and A. hydrophila L6) and phosphorus removal (C. denitrificans 110 with either A. calcoaceticus or A. hydrophila L6) were observed. B. denitrificans B79 was highly affected by interspecies interactions with respect to biofilm formation, denitrification activity and EPS composition, while C. denitrificans 110 remained largely unaffected. In some of the dual and quadruple strain biofilms new exopolysaccharide monomers were detected which were not present in the pure strain samples.

  • 2.
    Andersson, Sofia
    et al.
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Dalhammar, Gunnel
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Land, Carl Johan
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Biological nutrient removal by individual and mixed strain biofilmsManuscript (Other academic)
  • 3.
    Andersson, Sofia
    et al.
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Dalhammar, Gunnel
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Land, Carl Johan
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Characterization of extracellular polymeric substances from denitrifying organism Comamonas denitrificans2009In: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 82, no 3, p. 535-543Article in journal (Refereed)
    Abstract [en]

    Extracellular polymeric substances (EPS) play an important role in the formation and activity of biofilms in wastewater treatment (WWT). The EPS of the denitrifying biomarker Comamonas denitrificans strain 110, produced in different culture media and growth modes, were characterized. The EPS mainly contained protein (3-37%), nucleic acids (9-50%), and carbohydrates (3-21%). The extracellular DNA was found to be important for initial biofilm formation since biofilm, but not planktonic growth, was inhibited in the presence of DNase. The polysaccharide fraction appeared to consist of at least two distinct polymers, one branched fraction (A) made up of glucose and mannose with a molecular weight around 100 kDa. The other fraction (B) was larger and consisted of ribose, mannose, glucose, rhamnose, arabinose, galactose, and N-acetylglucosamine. Fraction B polysaccharides were mainly found in capsular EPS which was the dominant type in biofilms and agar-grown colonies. Fraction A was abundant in the released EPS, the dominant type in planktonic cultures. Biofilm and agar-grown EPS displayed similar overall properties while planktonic EPS showed clear compositional disparity. This study presents results on the physiology of a key WWT organism, which may be useful in the future development of improved biofilm techniques for WWT purposes.

  • 4.
    Andersson, Sofia
    et al.
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Dalhammar, Gunnel
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Persistence and competition of denitrifying biofilms subjected to a natural wastewater floraManuscript (Other academic)
  • 5.
    Andersson, Sofia
    et al.
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Land, Carl Johan
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Dalhammar, Gunnel
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Biofilm formation and interactions of bacterial strains found in wastewater treatment systems2008In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 283, no 1, p. 83-90Article in journal (Refereed)
    Abstract [en]

    Biofilm formation and adherence properties of 13 bacterial strains commonly found in wastewater treatment systems were studied in pure and mixed cultures using a crystal violet microtiter plate assay. Four different culture media were used, wastewater, acetate medium, glucose medium and diluted nutrient broth. The medium composition strongly affected biofilm formation. All strains were able to form pure culture biofilms within 24 h in at least one of the tested culture media and three strains were able to form biofilm in all four culture media, namely Acinetobacter calcoaceticus ATCC 23055, Comamonas denitrificans 123 and Pseudomonas aeruginosa MBL 0199. The adherence properties assessed were initial adherence, cell surface hydrophobicity, and production of amyloid fibers and extracellular polymeric substances. The growth of dual-strain biofilms showed that five organisms formed biofilm with all 13 strains while seven formed no or only weak biofilm when cocultured. In dual-strain cultures, strains with different properties were able to complement each other, giving synergistic effects. Strongest biofilm formation was observed when a mixture of all 13 bacteria were grown together. These results on attachment and biofilm formation can serve as a tool for the design of tailored systems for the degradation of municipal and industrial wastewater.

  • 6.
    Andersson, Sofia
    et al.
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Nilsson, Mirja
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Dalhammar, Gunnel
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Assessment of carrier materials for biofilm formation and denitrification2008In: Vatten, ISSN 0042-2886, Vol. 64, p. 201-207Article in journal (Refereed)
  • 7.
    Axelsson, Karolin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Konstanzer, Vera
    Kuttuva Rajarao, Guna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Terenius, Olle
    Dep of Ecology, SLU.
    Seriot, Lisa
    Nordenhem, Henrik
    Dep. of Ecology, SLU.
    Nordlander, Göran
    Dep. of Ecology, SLU.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Antifeedants produced by bacteria associated to the gut of the pine weevil (Hylobius abietis)Manuscript (preprint) (Other academic)
  • 8.
    Axelsson, Karolin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Biotechnology (BIO).
    Konstanzer, Vera
    KTH.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Terenius, Olle
    Seriot, Lisa
    KTH, School of Biotechnology (BIO).
    Nordenhem, Henrik
    Nordlander, Goran
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Tartu University, Estonia.
    Antifeedants Produced by Bacteria Associated with the Gut of the Pine Weevil Hylobius abietis2017In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 74, no 1, p. 177-184Article in journal (Refereed)
    Abstract [en]

    The pine weevil, Hylobius abietis, is a severe forest pest insect as it feeds on newly planted conifer seedlings. To identify and develop an antifeedant could be one step towards the protection of seedlings from feeding damage by the pine weevil. With the aim to trace the origin of the antifeedants previously found in feces of the pine weevil, we investigated the culturable bacteria associated with the gut and identified the volatiles they produced. Bacterial isolates were identified by 16S ribosomal RNA gene analysis. The volatile emissions of selected bacteria, cultivated on NB media or on the grated phloem of Scots pine twigs dispersed in water, were collected and analyzed by solid-phase microextraction gas chromatography-mass spectrometry. The bacterial isolates released a variety of compounds, among others 2-methoxyphenol, 2-phenylethanol, 3-methyl-1-butanol, 1-octen-3-ol, 3-octanone, dimethyl disulfide, and dimethyl trisulfide. A strong antifeedant effect was observed by 2-phenylethanol, which could thus be a good candidate for use to protect planted conifer seedlings against feeding damage caused by H. abietis.

  • 9.
    Azeem, Muhammad
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry. Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, Abbottabad 22060, Pakistan.
    Barba Aliaga, Marina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Borg-Karlson, Anna-Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry. Division of Organic Chemistry, Institute of Technology, Tartu University, Tartu 50411, Estonia.
    Terenius, O.
    Broberg, A.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Heterobasidion-growth inhibiting Bacillus subtilis A18 exhibits medium- and age-dependent production of lipopeptides2019In: Microbiology Research, ISSN 0944-5013, E-ISSN 1618-0623, Vol. 223-225, p. 129-136Article in journal (Refereed)
    Abstract [en]

    Heterobasidion annosum s.s. and H. parviporum are severe pathogens of conifers causing butt rot and root rot thus reducing the economic value of timber. Here, the antifungal activity of Bacillus subtilis isolate A18 against these two Heterobasidion species was investigated. Five different culture media with different culture age were investigated to study the effect of substrate composition and culture age for metabolite production. Bacterial cultures and cell-free culture filtrates were tested for antifungal activity. Inhibition of fungal growth was analysed using the agar disc-diffusion method. MALDI-TOF and LC-HRMS analyses were used to identify the antifungal metabolites. Substrate composition and age of culture were found to be active variables with direct effect on the antifungal activity of bacterial culture extracts. High anti-fungal activity was observed when B. subtilis was cultured in PDB, SGB and LB media for four days. Mass-spectrometry analysis showed the presence of lipopeptides in culture filtrates identified as members of the surfactins, polymixins, kurstakins and fengycins. A culture filtrate containing fengycin-type lipopeptides showed the highest bioactivity against Heterobasidion species. Bacterial cultures had higher bioactivity compared to their respective cell free culture filtrates. The results of the present study suggest that B. subtilis A18 is a powerful biocontrol agent against Heterobasidion infections of tree wounds and stumps.

  • 10.
    Azeem, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Borg-Karlson, Anna Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Antagonistic activity of Bacillus subtilis A18 – A19 against Heterobasidion speciesArticle in journal (Other academic)
  • 11.
    Azeem, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Borg-Karlson, Anna Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Sustainable bio-production of styrene from forest waste2013In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 144, p. 684-688Article in journal (Refereed)
    Abstract [en]

    A strain of Penicillium expansum was studied for the production of styrene using forest waste biomass as a feeding substrate. The fungal strain was cultivated on bark of various trees supplemented with yeast extract and the volatiles produced were collected on Tenax TA and analyzed by gas chromatography-mass spectrometry. Fungus cultured on grated soft bark of pine (Pinus sylvestris) stems (GPB) and mature bark of oak (Quercus robur) supplemented with yeast extract produced relatively the highest amounts of styrene. The maximum styrene production rate was 52.5 mu g/h, 41 mu g/h and 27 mu g/h from fungus cultivated on 50 mL liquid media with 10 g GPB or mature bark of oak and potato dextrose broth respectively. These promising results suggest that the fungal strain could be used to produce "green" styrene plastics using renewable forest waste biomass.

  • 12.
    Azeem, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Nagahama, Kazuhiro
    Terenius, Olle
    Dept of genetics microbiology and toxicology, Stockholm University.
    Nordenhem, Henrik
    SLU, Uppsala.
    Nordlander, Göran
    SLU, Uppsala.
    Borg-Karlson, Anna Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Chemo- and biodiversity of microbes associated with pine weevil (Hylobius abietis)Manuscript (preprint) (Other academic)
  • 13.
    Azeem, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology (closed September 2009).
    Nordenhem, Henrik
    SLU, Uppsala.
    Nordlander, Göran
    SLU, Uppsala.
    Borg-Karlson, Anna Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Penicillium expansum Volatiles Reduce Pine Weevil Attraction to Host Plants2013In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 39, no 1, p. 120-128Article in journal (Refereed)
    Abstract [en]

    The pine weevil Hylobius abietis (L.) is a severe pest of conifer seedlings in reforested areas of Europe and Asia. To identify minimally toxic and ecologically sustainable compounds for protecting newly planted seedlings, we evaluated the volatile metabolites produced by microbes isolated from H. abietis feces and frass. Female weevils deposit feces and chew bark at oviposition sites, presumably thus protecting eggs from feeding conspecifics. We hypothesize that microbes present in feces/frass are responsible for producing compounds that deter weevils. Here, we describe the isolation of a fungus from feces and frass of H. abietis and the biological activity of its volatile metabolites. The fungus was identified by morphological and molecular methods as Penicillium expansum Link ex. Thom. It was cultured on sterilized H. abietis frass medium in glass flasks, and volatiles were collected by SPME and analyzed by GC-MS. The major volatiles of the fungus were styrene and 3-methylanisole. The nutrient conditions for maximum production of styrene and 3-methylanisole were examined. Large quantities of styrene were produced when the fungus was cultured on grated pine bark with yeast extract. In a multi-choice arena test, styrene significantly reduced male and female pine weevils' attraction to cut pieces of Scots pine twigs, whereas 3-methylanisole only reduced male weevil attraction to pine twigs. These studies suggest that metabolites produced by microbes may be useful as compounds for controlling insects, and could serve as sustainable alternatives to synthetic insecticides.

  • 14.
    Azeem, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. COMSATS Inst Informat Technol, Dept Chem, Abbottabad 22060, Pakistan.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Terenius, Olle
    Nordlander, Goran
    Nordenhem, Henrik
    Nagahama, Kazuhiro
    Norin, Emil
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Borg Karlsson, Anna Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    A fungal metabolite masks the host plant odor for the pine weevil (Hylobius abietis)2015In: Fungal ecology, ISSN 1754-5048, E-ISSN 1878-0083, Vol. 13, p. 103-111Article in journal (Refereed)
    Abstract [en]

    The pine weevil is one of the most important pest insects of conifer reforestation areas in Europe. Female pine weevils cover their eggs with chewed bark and feces (frass) resulting in avoidance behavior of feeding conspecifics towards egg laying sites. It has been suggested that microorganisms present in the frass may be responsible for producing deterrent compounds for the pine weevil. The fungi Ophiostoma canum, O. pluriannulatum, and yeast Debaryomyces hansenii were isolated from aseptically collected pine-weevil frass. The isolated fungi were cultured on weevil frass broth and their volatiles were collected by SPME and identified by GC MS. D. hansenii produced methyl salicylate (MeS) as a major compound, whereas, in addition, O. canum and O. pluriannulatum produced 6-protoilludene. In a multi-choice lab bioassay, MeS strongly reduced pine weevil's attraction to the Pinus sylvestris volatiles. Thus, a fungal metabolite was found that strongly affects the pine weevil host-odor search. (C) 2014 Elsevier Ltd and The British Mycological Society. All rights reserved.

  • 15.
    Azeem, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Norin, Emil
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Terenius, Olle
    Dept of genetics microbiology and toxicology, Stockholm University.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Nordlander, Göran
    SLU, Uppsala.
    Nordenhem, Henrik
    SLU, Uppsala.
    Borg-Karlson, Anna Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fungal metabolite mask the host plant odor of the pine weevil (Hylobius abietis)Article in journal (Other academic)
  • 16.
    Azeem, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Department of Chemistry, COMSATS Institute of Information Technology, Abbottabad, Pakistan.
    Terenius, Olle
    Rajarao, Gunaratna Kuttuva
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Nagahama, Kazuhiro
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Sojo University, Faculty of Biotechnology and Life Science, Department of Applied Microbial Technology, 4-22-1 Ikeda, Nishi-ku, Kumamoto, Japan.
    Nordenhem, Henrik
    Nordlander, Goran
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Tartu University, Institute of Technology, Division of Organic Chemistry, Tartu, Estonia.
    Chemodiversity and biodiversity of fungi associated with the pine weevil Hylobius abietis2015In: Fungal Biology, ISSN 1878-6146, E-ISSN 1878-6162, Vol. 119, no 8, p. 738-46Article in journal (Refereed)
    Abstract [en]

    The pine weevil Hylobius abietis is a severe pest of conifer seedlings in reforestation areas. Weevils lay eggs in the root bark or in the soil near roots of recently dead trees and cover the eggs with frass (feces combined with chewed bark), possibly to avoid conspecific egg predation. The aim of the present investigation focused on isolation, identification, and volatile production of fungi from pine-weevil feces and frass. Fungi were isolated from weevil frass and feces separately, followed by identification based on ITS sequencing. Fifty-nine isolates belonging to the genera Penicillium, Ophiostoma, Mucor, Leptographium, Eucasphaeria, Rhizosphaera, Debaryomyces, and Candida were identified. Volatile organic compounds (VOCs) produced by the fungal community and fungal isolates cultured on weevil-frass broth were identified by SPME-GCMS. Major VOCs emitted from the fungal community and pure isolates were species- and strain specific and included isopentylalcohol, styrene, 3-octanone, 6-protoilludene, methyl salicylate, 3-methylanisole, 2-methoxyphenol, and phenol. Some of these are known to influence the orientation of pine weevils when tested among highly attractive newly planted conifer seedlings.

  • 17. Bayat, N.
    et al.
    Lopes, V. R.
    Sanchez-Dominguez, M.
    Lakshmanan, Ramnath
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Cristobal, S.
    Assessment of functionalized iron oxide nanoparticles in vitro: introduction to integrated nanoimpact index2015In: Environmental Science: Nano, ISSN 2051-8153, Vol. 2, no 4, p. 380-394Article in journal (Refereed)
    Abstract [en]

    Functionalization of super paramagnetic iron oxide NPs (SPIONs) with different coatings renders them with unique physicochemical properties that allow them to be used in a broad range of applications such as drug targeting and water purification. However, it is required to fill the gap between the promises of any new functionalized SPIONs and the effects of these coatings on the NPs safety. Nanotoxicology is offering diverse strategies to assess the effect of exposure to SPIONs in a case-by-case manner but an integrated nanoimpact scale has not been developed yet. We have implemented the classical integrated biological response (IBR) into an integrated nanoimpact index (INI) as an early warning scale of nano-impact based on a combination of toxicological end points such as cell proliferation, oxidative stress, apoptosis and genotoxicity. Here, the effect of SPIONs functionalized with tri-sodium citrate (TSC), polyethylenimine (PEI), aminopropyl-triethoxysilane (APTES) and Chitosan (chitosan) were assessed on human keratinocytes and endothelial cells. Our results show that endothelial cells were more sensitive to exposure than keratinocytes and the initial cell culture density modulated the toxicity. PEI-SPIONs had the strongest effects in both cell types while TSC-SPIONS were the most biocompatible. This study emphasizes not only the importance of surface coatings but also the cell type and the initial cell density on the selection of toxicity assays. The INI developed here could offer an initial rationale to choose either modifying SPIONs properties to reduce its nanoimpact or performing a complete risk assessment to define the risk boundaries.

  • 18.
    Bodlund, Ida
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Pavankumar, Asalapuram Ramachand
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Chelliah, R.
    Anna University, Chennai.
    Kasi, S.
    Anna University, Chennai.
    Sankaran, K.
    Anna University, Chennai.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Coagulant proteins identified in Mustard: a potential water treatment agent2014In: International Journal of Environmental Science and Technology, ISSN 1735-1472, E-ISSN 1735-2630, Vol. 11, no 4, p. 873-880Article in journal (Refereed)
    Abstract [en]

    The use of natural coagulant protein in drinking water treatment has been discussed for a long time, though the method is still not in practice, probably due to limited knowledge and availability of material. In the present work, different Mustard varieties were tested for the presence of coagulant protein compared with Moringa seed extract and their potential application in water treatment. The coagulation activity of the protein extract was measured using synthetic clay solution as well as water from pond. The protein content was determined by Bradford method, molecular mass determined by Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and peptide sequence was analyzed by Mass spectrometry. Extract of Mustard (large) and Moringa seed showed coagulation activity of a parts per thousand...70 and a parts per thousand...85 % after 90 min, respectively. Interestingly, seed extracts from other Mustard varieties had coagulation activity after heat activation at 95 A degrees C for 5 h. However, the coagulation activity of Mustard seed extract against turbid pond water was higher (a parts per thousand...60 %) compared to Moringa seed extract (a parts per thousand...50 %). The peptide sequence analysis of 6.5 and 9 kDa proteins was found to be homologous to Moringa coagulant protein and napin3, respectively. To our knowledge, this could be the first report on Mustard seed having coagulant protein. The coagulation activity of Mustard (large) against highly turbid pond water suggested that it could be a potential natural coagulant for water treatment.

  • 19.
    Bodlund, Ida
    et al.
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Sabarigirisan, K
    Anna University, Chennai.
    Chelliah, R
    Anna University, Chennai.
    Sankaran, K
    Anna University, Chennai.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Screening of Coagulant Proteins from Plant Materials in Southern IndiaManuscript (preprint) (Other academic)
  • 20.
    Bodlund, Ida
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Sabarigrisan, K.
    Chelliah, R.
    Sankaran, K.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Screening of coagulant proteins from plant material in southern India2013In: Water Science and Technology: Water Supply, ISSN 1606-9749, E-ISSN 1607-0798, Vol. 13, no 6, p. 1478-1485Article in journal (Refereed)
    Abstract [en]

    Access to fresh water is limited due to the growing population and to provide safe drinking water is a global challenge. In this initial study, about a hundred different samples were screened for coagulation activity. Amongst the plants tested were fruits and vegetable pulps, leaves and seeds (like jackfruit, tamarind, papaya, orange, watermelon, pineapple, cucumber, green gram, peas, black gram, cluster bean rice, maize, chili, cabbage, mustard, cauliflower, beetroot and carrot). The crude extracts were prepared in water and salt solution in order to extract the coagulant protein and compare the coagulation activity. Among the tested samples, only a few seed extracts showed coagulation activity. The seed extracts of mustard and cabbage showed coagulation activity in both water and salt extracts and were comparable to that of Moringa seed extract. The salt extracts showed higher activity compared to that of water extract in most of the samples tested. The coagulation activity was stable after incubation at 95 WC for 5 hours implying heat resistance. A protein profile analysis showed major protein bands with a molecular weight around 6.5 and 9 kDa. In this preliminary study, mustard and cabbage seed extracts were promising in terms of coagulation and heat resistance, so could be an alternative to Moringa seed for water treatment and should be investigated further.

  • 21.
    Chelliah, R
    et al.
    Anna University, Chennai.
    Bodlund, Ida
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Sankaran, K
    Anna University, Chennai.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Antibacterial activity of Mustard and Moringa seed extracts against pathogenic organismsManuscript (preprint) (Other academic)
  • 22. Dryselius, R.
    et al.
    Aswasti, S. K.
    Kuttuva, Gunaratna R.
    KTH, Superseded Departments, Biotechnology.
    Nielsen, P. E.
    Good, L.
    The translation start codon region is sensitive to antisense PNA inhibition in Escherichia coli2003In: Oligonucleotides, ISSN 1545-4576, Vol. 13, no 6, p. 427-433Article in journal (Refereed)
    Abstract [en]

    Antisense peptide nucleic acids (PNA) can inhibit bacterial gene expression with gene and sequence specificity. Using attached carrier peptides that aid cell permeation, the antisense effects when targeting essential genes are sufficient to prevent growth and even kill bacteria. However, many design uncertainties remain, including the difficult question of target sequence selection. In this study, we synthesized 90 antisense peptide-PNAs to target sequences in a head to tail manner across the entire length of the mRNA encoding beta-lactamase. The results from this scan pointed to the start codon region as most sensitive to inhibition. To confirm and refine the result, a higher-resolution scan was conducted over the start codon region of the beta-lactamase gene and the essential Escherichia coli acpP gene. For both genes, the start codon region, including the Shine-Dalgarno motif, was sensitive, whereas antisense agents targeted outside of this region were largely ineffective. These results are in accord with natural antisense mechanisms, which typically hinder the start codon region, and the sensitivity of this region should hold true for most bacterial genes as well as for other RNase H-independent antisense agents that rely on a steric blocking mechanism. Therefore, although other design parameters are also important, the start codon region in E. coli mRNA is the most reliable target site for antisense PNAs.

  • 23.
    Eneh, Lynda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Borg Karlsson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fillinger, Ulrike
    Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Lindh, Jenny
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Factors associated with preferred Anopheles gambiae s.l. oviposition sitesManuscript (preprint) (Other academic)
  • 24.
    Eneh, Lynda
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Fillinger, U.
    Human Hlth Theme, Int Ctr Insect Physiol & Ecol, Thomas Odhiambo Campus, Mbita, Kenya..
    Borg-Karlson, Anna-Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Rajarao, Gunaratna Kuttuva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Lindh, Jenny
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Anopheles arabiensis oviposition site selection in response to habitat persistence and associated physicochemical parameters, bacteria and volatile profiles2019In: Medical and Veterinary Entomology, ISSN 0269-283X, E-ISSN 1365-2915, Vol. 33, no 1, p. 56-67Article in journal (Refereed)
    Abstract [en]

    A better understanding of the oviposition behaviour of malaria vectors might facilitate the development of new vector control tools. However, the factors that guide the aquatic habitat selection of gravid females are poorly understood. The present study explored the relative attractiveness of similar artificial ponds (0.8 m(2)) aged at varying lengths prior to opening in such a way that wild Anopheles arabiensis could choose between ponds that were freshly set up, or were aged 4 or 17 days old, to lay eggs. Physicochemical parameters, bacterial profile and volatile organic compounds emitted from ponds were investigated over three experimental rounds. Fresh ponds contained on average twice as many An. arabiensis instar larvae (mean 50, 95% confidence interval (CI) = 29-85) as the ponds that had aged 4 days (mean = 24, 95% CI = 14-42) and 17 days (mean = 20, 95% CI: 12-34). Fresh ponds were associated with a significantly higher turbidity combined with higher water temperature, higher nitrite levels and a lower pH and chlorophyll level than the older ponds. Round by round analyses suggested that bacteria communities differed between age groups and also that 4-heptanone, 2-ethylhexanal and an isomer of octenal were exclusively detected from the fresh ponds. These characteristics may be useful with respect to developing attract and kill strategies for malaria vector control.

  • 25.
    Eneh, Lynda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fillinger, Ulrike
    Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lindh, Jenny
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Oviposition choice of malaria mosquitoes Anopheles gambiae s.l.:  do they choose between similar habitats?Manuscript (preprint) (Other academic)
  • 26.
    Eneh, Lynda K.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Saijo, Hiromi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lindh, Jenny M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Cedrol, a malaria mosquito oviposition attractant is produced by fungi isolated from rhizomes of the grass Cyperus rotundus2016In: Malaria Journal, ISSN 1475-2875, E-ISSN 1475-2875, Vol. 15, article id 478Article in journal (Refereed)
    Abstract [en]

    Background: Cedrol, a sesquiterpene alcohol, is the first identified oviposition attractant for African malaria vectors. Finding the natural source of this compound might help to elucidate why Anopheles gambiae and Anopheles arabiensis prefer to lay eggs in habitats containing it. Previous studies suggest that cedrol may be a fungal metabolite and the essential oil of grass rhizomes have been described to contain a high amount of different sesquiterpenes. Results: Rhizomes of the grass Cyperus rotundus were collected in a natural malaria mosquito breeding site. Two fungi were isolated from an aqueous infusion with these rhizomes. They were identified as Fusarium falciforme and a species in the Fusarium fujikuroi species complex. Volatile compounds were collected from the headspace above fungal cultures on Tenax traps which were analysed by gas chromatography-mass spectrometry (GCMS). Cedrol and a cedrol isomer were detected in the headspace above the F. fujikuroi culture, while only cedrol was detected above the F. falciforme culture. Conclusion: Cedrol an oviposition attractant for African malaria vectors is produced by two fungi species isolated from grass rhizomes collected from a natural mosquito breeding site.

  • 27.
    Eneh, Lynda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Saijo, Hiromi
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lindh, Jenny
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Cedrol, a malaria mosquito oviposition attractant is produced by fungi isolated from rhizomes of the grass Cyperus rotundusManuscript (preprint) (Other academic)
  • 28.
    Feng, Zhaoxuan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Odelius, Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Microwave carbonized cellulose for trace pharmaceutical adsorption2018In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 346, p. 557-566Article in journal (Refereed)
    Abstract [en]

    A promising sustainable strategy to valorize cellulose to high-value adsorbents for trace pharmaceuticals, like diclofenac sodium (DCF), in the water is demonstrated. Carbon nanospheres (CN) as the DCF adsorbent were derived from cellulose through a one-pot microwave-assisted hydrothermal carbonization method. CN exhibited efficient DCF removal (100% removal of 0.001 mg/mL DCF in 30 s and 59% removal of 0.01 mg/mL DCF in 1 h). The adsorption kinetics and isotherm data were well-fitted with the pseudo-second-order kinetic model and Langmuir model, respectively. The adsorption process was endothermic and spontaneous as confirmed by the thermodynamic parameters. Multiple characterization techniques including SEM/EDS, FTIR, FTIR-imaging and zeta potential were applied to qualitatively investigate the adsorption process. π-π stacking and hydrogen bonding were proposed as the dominant adsorption interactions. CN also demonstrated effective adsorption capacity towards three other commonly-detected contaminants in the wastewater including ketoprofen (KP), benzophenone (BZP), and diphenylamine (DPA), each bearing partial structural similarity with DCF. The affinity of the contaminants towards CN followed the order DPA > BZP > DCF > KP, which could be explained by the different configurations and chemical units. It was speculated that for DCF and KP, the steric hindrance and electrostatic repulsion produced by dissociated carboxyl groups can impede the adsorption process as compared to DPA and BZP. This methodology could offer further insights into the drug adsorption on the cellulose-derived carbon adsorbents and the use of bioderived carbons for treatment of wastewaters contaminated with pharmaceuticals.

  • 29.
    Kuttuva, Gunaratna R.
    et al.
    KTH, Superseded Departments, Biotechnology.
    Nekhotiaeva, N.
    Good, L.
    Peptide-mediated delivery of green fluorescent protein into yeasts and bacteria2002In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 215, no 2, p. 267-272Article in journal (Refereed)
    Abstract [en]

    Stringent microbial cell barriers limit the application of many substances in research and therapeutics. Carrier peptides that penetrate or translocate across cell membranes may help overcome this problem. To assess peptide-mediated delivery into two yeast and three bacterial species, a range of cell penetrating and signal peptide sequences were fused to green fluorescent protein (GFP), expressed in Escherichia coli, partially purified and incubated with growing cells. Fluorescence microscopy indicated several peptides that mediated delivery. In particular, VLTNENPFSDP efficiently delivered GFP into Candida albicans and Staphylococcus aureus, while YKKSNNPFSD was most efficient for Bacillus subtilis and CFFKDEL for Escherichia coli. Carrier peptides may improve delivery of certain large molecular mass molecules into microorganisms for research and therapeutic applications.

  • 30.
    Kuttuva, Gunaratna R.
    et al.
    KTH, Superseded Departments, Biotechnology.
    Nekhotiaeva, N.
    Good, L.
    The signal peptide NPFSD fused to ricin A chain enhances cell uptake and cytotoxicity in Candida albicans2003In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 301, no 2, p. 529-534Article in journal (Refereed)
    Abstract [en]

    Microorganisms possess stringent cell membranes which limit the cellular uptake of antimicrobials. One strategy to overcome these barriers is to attach drugs or research reagents to carrier peptides that enter cells by passive permeation or active uptake. Here the short endocytosis signal peptide NPFSD was found to efficiently deliver both FITC and GFP,into Saccharomyces cerevisiae and Candida albicans with uptake into the majority of cells in a population. The NPFSD signal is itself non-toxic, but when fused to the ricin A chain toxin (RTA) the peptide enhanced both cell uptake and toxicity against C albicans, which like other yeasts is resistant to naked RTA. Cell entry required at least 1 h incubation, temperatures above 4degreesC, and an energy source, and uptake was outcompeted with free peptide. Therefore, the NPFSD peptide can carry a range of compounds into yeasts and this delivery route holds promise to enhance the activity of antifungals.

  • 31.
    Kuttuva Rajarao, Gunaratna
    et al.
    KTH, School of Biotechnology (BIO), Bioprocess Technology (closed 20130101).
    Shokri, Atefeh
    KTH, School of Biotechnology (BIO), Bioprocess Technology (closed 20130101).
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Jacks, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Bundschuh, Jochen
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Von Brömssen, M.
    Microbial characterization of Holocene alluvial sediments in the Meghna Flood Plain of Matlab Upazila, Bangladesh2010In: Arsenic in Geosphere and Human Diseases, As 2010 - 3rd International Congress: Arsenic in the Environment, 2010, p. 140-142Conference paper (Refereed)
  • 32.
    Lakshmanan, Ramnath
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Bayat, Narges
    Stockholm University, Department of Biochemistry and Biophysics.
    R-Lopes, Viviana
    Linköping University, Department of Clinical and Experimental Medicine.
    Cristobal, Susana
    Linköping University, Department of Clinical and Experimental Medicine.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Synthesis, characterization and toxicity assessment of magnetic nanoparticles on skin and endothelial cells in vitro: water treatment applicationManuscript (preprint) (Other academic)
  • 33.
    Lakshmanan, Ramnath
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Effective water content reduction in sewage wastewater sludge using magnetic nanoparticlesManuscript (preprint) (Other academic)
  • 34.
    Lakshmanan, Ramnath
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Effective water content reduction in sewage wastewater sludge using magnetic nanoparticles2014In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 153, p. 333-339Article in journal (Refereed)
    Abstract [en]

    The present work compares the use of three flocculants for sedimentation of sludge and sludge water content from sewage wastewater i.e. magnetic iron oxide nanoparticles (MION), ferrous sulfate (chemical) and Moringa crude extract (protein). Sludge water content, wet/dry weight, turbidity and color were performed for, time kinetics and large-scale experiment. A 30% reduction of the sludge water content was observed when the wastewater was treated with either protein or chemical coagulant. The separation of sludge from wastewater treated with MION was achieved in less than 5. min using an external magnet, resulted in 95% reduction of sludge water content. Furthermore, MION formed denser flocs and more than 80% reduction of microbial content was observed in large volume experiments. The results revealed that MION is efficient in rapid separation of sludge with very low water content, and thus could be a suitable alternative for sludge sedimentation and dewatering in wastewater treatment processes.

  • 35.
    Lakshmanan, Ramnath
    et al.
    KTH, School of Biotechnology (BIO), Bioprocess Technology (closed 20130101).
    Okoli, Chuka
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology. KTH, School of Biotechnology (BIO), Bioprocess Technology (closed 20130101).
    Boutonnet, Magali
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Järås, Sven
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Bioprocess Technology (closed 20130101).
    Effect of Magnetic Iron Oxide Nanoparticles for Surface Water Treatment: Trace Minerals and MicrobesManuscript (preprint) (Other academic)
  • 36.
    Lakshmanan, Ramnath
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Okoli, Chuka
    KTH, School of Biotechnology (BIO), Industrial Biotechnology. KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Boutonnet, Magali
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Järås, Sven
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Effect of magnetic iron oxide nanoparticles in surface water treatment: Trace minerals and microbes2013In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 129, p. 612-615Article in journal (Refereed)
    Abstract [en]

    The existing water treatment process often uses chemicals, which is of high health and environmental concern. The present study focused on the efficiency of microemulsion prepared magnetic iron oxide nanoparticles (ME-MIONs) and protein-functionalized nanoparticles (MOCP. +. ME-MIONs) in water treatment. Their influence on mineral ions and microorganisms present in the surface water from lake Brunnsviken and örlången, Sweden were investigated. Ion analysis of water samples before and after treatment with nanoparticles was performed. Microbial content was analyzed by colony forming units (CFU/ml). The results impart that ME-MIONs could reduce the water turbidity even in low turbid water samples. Reduction of microbial content (98%) was observed at 37 °C and more than 90% reduction was seen at RT and 30 °C when compared to untreated samples from lake örlången. The investigated surface water treatment method with ME-MIONs was not significantly affecting the mineral ion composition, which implies their potential complement in the existing treatment process.

  • 37.
    Lakshmanan, Ramnath
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Okoli, Chuka
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Boutonnet, Magali
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Järås, Sven
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Microemulsion prepared magnetic nanoparticles for phosphate removal: Time efficient studies2014In: Journal of Environmental Chemical Engineering, ISSN 2213-3437, Vol. 2, no 1, p. 185-189Article in journal (Refereed)
    Abstract [en]

    The present study investigates the effective removal of phosphate in sewage wastewater using magnetic iron oxide nanoparticles (MION). The microemulsion-prepared magnetic iron oxide nanoparticles (ME-MION) of around 7-10 nm was synthesized using water-in-oil microemulsion method. The interaction of ME-MION and phosphate was studied using In situ FT-IR technique. Batch experiments were carried out with wastewater to determine the conc. and time efficiency using ME-MION for removal of phosphate. The vibration peak at 1004 cm-1 and the presence of hydroxyl group (OH-) at 3673 cm-1 confirms the binding of phosphate to ME-MION. ME-MION with 0.44 g L-1 exhibited more than 95% phosphate reduction in 5 min and close to 100% in 20 min. Conversely the experimental data obtained has been fitted with Langmuir isotherm model and also exhibited high correlation coefficients. The ME-MION was regenerated and can be reused for minimum 5 consecutive times. Efficient and fast reduction of phosphate was attained while the recovery of nanoparticles was achieved by an external magnetic field. To the author's knowledge, this is the first report that underscores around 100% phosphate removal from wastewater using ME-MION in 20 min. The approach utilized in this study offers a potential technique in the reduction of phosphate in wastewater whilst, reducing the time and reuse of nanoparticles.

  • 38.
    Lakshmanan, Ramnath
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Rajaraman, P.
    Okoli, Chuka
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Boutonnet, Magali
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Järås, Sven
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Application of magnetic nanoparticles for wastewater treatment using response surface methodology2013In: Technical Proceedings of the 2013 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2013: Volume 3, 2013, 2013, p. 690-693Conference paper (Refereed)
    Abstract [en]

    Nanotechnology is considered as one of the key techniques that provide unique materials with high reactivity due to large surface to volume ratio and which could address the fundamental issues in water sector and environment. The present study investigates the efficiency of magnetic iron oxide nanoparticles in wastewater treatment based on Central Composite Face centered (CCF) matrix of response surface methodology for the reduction of turbidity and total nitrogen. The multiple linear regression fit (MLR) obtained for turbidity (r2 0.97) and total nitrogen reduction (r 0.94) supports the future predictions obtaining a significant model. The maximum reduction of turbidity and total nitrogen achieved was 93% and 41% respectively. Other contaminants such as color, total organic carbon, nitrate and microbial content could be reduced. The present study reveals that magnetic property, time and reduction of pollutants by magnetic nanoparticles could impart an efficient treatment process.

  • 39.
    Lakshmanan, Ramnath
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Rajaraman, Premanand
    Sri Sairam Engineering College, Department of Physics.
    Okoli, Chuka
    KTH, School of Biotechnology (BIO), Industrial Biotechnology. KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Boutonnet, Magali
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Järås, Sven
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Application of Magnetic Nanoparticles for the removal of turbidity and total nitrogen from sewage wastewater: Modelling studiesManuscript (preprint) (Other academic)
  • 40.
    Lakshmanan, Ramnath
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Sanchez-Dominguez, Margarita
    Centro de Investigacion en Materials Avanzados (CIMAV) S.C., Mexico.
    Matutes-Aquino, Jose
    Centro de Investigacion en Materials Avanzados (CIMAV) S.C., Mexico.
    Wennmalm, Stefan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Removal of total organic carbon from sewage wastewater using poly(ethylenimine)-functionalized magnetic nanoparticles2014In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, no 4, p. 1036-1044Article in journal (Refereed)
    Abstract [en]

    The increased levels of organic carbon in sewage wastewater during recent years impose a great challenge to the existing wastewater treatment process (WWTP). Technological innovations are therefore sought that can reduce the release of organic carbon into lakes and seas. In the present study, magnetic nanoparticles (NPs) were synthesized, functionalized with poly(ethylenimine) (PEI), and characterized using TEM (transmission electron microscopy), X-ray diffraction (XRD), FTIR (Fourier transform infrared spectroscopy), CCS (confocal correlation spectroscopy), SICS (scattering interference correlation spectroscopy), magnetism studies, and thermogravimetric analysis (TGA). The removal of total organic carbon (TOC) and other contaminants using PEI-coated magnetic nanoparticles (PEI-NPs) was tested in wastewater obtained from the Hammarby Sjöstadsverk sewage plant, Sweden. The synthesized NPs were about 12 nm in diameter and showed a homogeneous particle size distribution in dispersion by TEM and CCS analyses, respectively. The magnetization curve reveals superparamagnetic behavior, and the NPs do not reach saturation because of surface anisotropy effects. A 50% reduction in TOC was obtained in 60 min when using 20 mg/L PEI-NPs in 0.5 L of wastewater. Along with TOC, other contaminants such as turbidity (89%), color (86%), total nitrogen (24%), and microbial content (90%) were also removed without significant changes in the mineral ion composition of wastewater. We conclude that the application of PEI-NPs has the potential to reduce the processing time, complexity, sludge production, and use of additional chemicals in the WWTP.

  • 41.
    Marobhe, Nancy
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Dalhammar, Gunnel
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Kuttuva, Gunaratna R.
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Effect of coagulant protein from Vigna and Parkinsonia seeds on bacteria isolated from Ruvu River in Tanzania2008In: World Journal of Microbiology & Biotechnology, ISSN 0959-3993, E-ISSN 1573-0972Article in journal (Other academic)
  • 42.
    Marobhe, Nancy
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Dalhammar, Gunnel
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Kuttuva, Gunaratna R.
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Simple and rapid methods for purification and characterization of active coagulants from the seeds of Vigna unguiculata and Parkinsonia aculeata2007In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 28, no 6, p. 671-681Article in journal (Refereed)
    Abstract [en]

    The coagulating properties of aqueous crude extracts and purified proteins of Vigna unguicilata and Parkinsomia aculeata seeds, which are traditional water coagulants in rural areas of Tanzania, were studied. The coagulation activity assays were done using one millilitre (ml) of kaolin water samples. Coagulating proteins were purified in two-step ion exchange chromatography. The properties of coagulant protein were compared with Moringa oleifera. Coagulating components eluted by 0.6 M NaCl in both coagulants are cationic proteins that have the molecular mass of about 6 kDa, which is very similar to that of M. oleifera. The proteins of V. unguiculata and P. aculeata eluted by 0.3 M NaCl also harbour coagulation activity but proteins eluted with 0.6 M NaCl have higher activity. The dosage for coagulation using purified proteins of both coagulants is about 5 to 10 times lower than that of crude seed extracts. The optimum floc settling time of water treated by crude seed extracts and purified proteins ranged between two and two and half hours. Coagulating proteins of both coagulants elated by 0.6 M NaCl are thermoresistant and retained coagulation activity of 87% to 92% after boiling for two hours at 80 degrees C and one hour at 95 degrees C. Thermotolerant proteins of V. unguiculata eluted by 0.6 M NaCl and P. aculeata have wider pH range of 5.5 to 8.5 for coagulation activity than those of M. oleifera proteins. The present investigation reveals the possibility of using purified natural coagulants for water treatment to produce safe drinking water.

  • 43. Mbwele, Lydia
    et al.
    Rajarao, Gunaratna
    Dalhammar, Gunnel
    Influence of microbial growth and carbon source in phosphorus uptake in wastewater treatmentManuscript (preprint) (Other academic)
  • 44. Mbwele, Lydia
    et al.
    Rajarao, Gunaratna
    Dalhammar, Gunnel
    Isolation of Phosphorus Removing Bacteria from a Waste Stabilisation Pond SystemManuscript (preprint) (Other academic)
  • 45. Nekhotiaeva, N.
    et al.
    Elmquist, A.
    Kuttuva, Gunaratna R.
    KTH, Superseded Departments, Biotechnology.
    Hallbrink, M.
    Langel, U.
    Good, L.
    Cell entry and antimicrobial properties of eukaryotic cell-penetrating peptides2003In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 17, no 15, p. 394-+Article in journal (Refereed)
    Abstract [en]

    Antimicrobial drug action is limited by both microbial and host cell membranes. Microbes stringently exclude the entry of most drugs, and mammalian membranes limit drug distribution and access to intracellular pathogens. Recently, cell-penetrating peptides (CPPs) have been developed as carriers to improve mammalian cell uptake. Given that CPP's are cationic and often amphipathic, similar to membrane active antimicrobial peptides, it may be possible to use CPP activity to improve drug delivery to microbes. Here, two CPPs, TP10 and pVEC, were found to enter a range of bacteria and fungi. The uptake route involves rapid surface accumulation within minutes followed by cell entry. TP10 inhibited Candida albicans and Staphylococcus aureus growth, and pVEC inhibited Mycobacterium smegmatis growth at low micromolar doses, below the levels that harmed human HeLa cells. Therefore, although TP10 and pVEC entered all cell types tested, they preferentially damage microbes, and this effect was sufficient to clear HeLa cell cultures from noninvasive S. aureus infection. Also, conversion of the cytotoxicity indicator dye SYTOX Green showed that TP10 causes rapid and lethal permeabilization of S. aureus and pVEC permeabilizes M. smegmatis, but not HeLa cells. Therefore, TP10 and pVEC can enter both mammalian and microbial cells and preferentially permeabilize and kill microbes.

  • 46.
    Nilsson, Charlotte
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Lakshmanan, Ramnath
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Efficacy of reactive mineral-based sorbents for phosphate, bacteria, nitrogen and TOC removal - Column experiment in recirculation batch mode2013In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 47, no 14, p. 5165-5175Article in journal (Refereed)
    Abstract [en]

    Two mineral-based materials (Polonite and Sorbulite) intended for filter wells in on-site wastewater treatment were compared in terms of removal of phosphate (PO4-P), total inorganic nitrogen (TIN), total organic carbon (TOC) and faecal indicator bacteria (Escherichia coli and Enterococci). Using an innovative, recirculating system, septic tank effluent was pumped at a hydraulic loading rate of 3000 L m(2) d(-1) into triplicate bench-scale columns of each material over a 90-day period. The results showed that Polonite performed better with respect to removal of PO4-P, retaining on average 80% compared with 75% in Sorbulite. This difference was attributed to higher CaO content in Polonite and its faster dissolution. Polonite also performed better in terms of removal of bacteria because of its higher pH value. The total average reduction in E. coli was 60% in Polonite and 45% in Sorbulite, while for Enterococci the corresponding value was 56% in Polonite and 34% in Sorbulite. Sorbulite removed TIN more effectively, with a removal rate of 23%, while Polonite removed 11% of TIN, as well as TOC. Organic matter (measured as TOC) was accumulated in the filter materials but was also released periodically. The results showed that Sorbulite could meet the demand in removing phosphate and nitrogen with reduced microbial release from the wastewater treatment process.

  • 47.
    Okoli, Chuka
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology. KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Boutonnet, Magali
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Järås, Sven
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Rajarao-Kuttuva, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology. Albanova University Center, Sweden.
    Protein-functionalized magnetic iron oxide nanoparticles: Time efficient potential-water treatment2014In: Nanotechnology for Sustainable Development, First Edition, Springer, 2014, p. 127-136Chapter in book (Other academic)
    Abstract [en]

    Recent advances in nanoscience suggest that the existing issues involving water quality could be resolved or greatly improved using nanomaterials, especially magnetic iron oxide nanoparticles. Magnetic nanoparticles have been synthesized for the development and use, in association with natural coagulant protein for water treatment. The nanoparticles size, morphology, structure, and magnetic properties were characterized by transmission electron microscope, X-ray diffraction, and superconducting quantum interference device magnetometry. Purified Moringa oleifera protein was attached onto microemulsions-prepared magnetic iron oxide nanoparticles (ME-MION) to form stable protein-functionalized magnetic nanoparticles (PMO+ME-MION). The turbidity removal efficiency in both synthetic and surface water samples were investigated and compared with the commonly used synthetic coagulant (alum) as well as PMO. More than 90 % turbidity could be removed from the surface waters within 12 min by magnetic separation of PMO+ME-MION; whereas gravimetrically, 70 % removal in high and low turbid waters can be achieved within 60 min. In contrast, alum requires 180 min to reduce the turbidity of low turbid water sample. These data support the advantage of separation with external magnetic field (magnetophoresis) over gravitational force. Time kinetics studies show a significant enhancement in ME-MION efficiency after binding with PMO implying the availability of large surface of the MEMION. The coagulated particles (impurities) can be removed from PMO+ME-MION by washing withmild detergent or cleaning solution. To our knowledge, this is the first report on surface water turbidity removal using protein-functionalized magnetic nanoparticle.

  • 48.
    Okoli, Chuka
    et al.
    KTH, School of Biotechnology (BIO), Environmental Microbiology. KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Boutonnet, Magali
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Järås, Sven
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Rajarao-Kuttuva, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Protein-functionalized magnetic iron oxide nanoparticles: time efficient potential-water treatment2012In: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 14, no 10, p. 1194-Article in journal (Refereed)
    Abstract [en]

    Recent advances in nanoscience suggest that the existing issues involving water quality could be resolved or greatly improved using nanomaterials, especially magnetic iron oxide nanoparticles. Magnetic nanoparticles have been synthesized for the development and use, in association with natural coagulant protein for water treatment. The nanoparticles size, morphology, structure, and magnetic properties were characterized by transmission electron microscope, X-ray diffraction, and superconducting quantum interference device magnetometry. Purified Moringa oleifera protein was attached onto microemulsions-prepared magnetic iron oxide nanoparticles (ME-MION) to form stable protein-functionalized magnetic nanoparticles (PMO+ME-MION). The turbidity removal efficiency in both synthetic and surface water samples were investigated and compared with the commonly used synthetic coagulant (alum) as well as PMO. More than 90 % turbidity could be removed from the surface waters within 12 min by magnetic separation of PMO? ME-MION; whereas gravimetrically, 70 % removal in high and low turbid waters can be achieved within 60 min. In contrast, alum requires 180 min to reduce the turbidity of low turbid water sample. These data support the advantage of separation with external magnetic field (magnetophoresis) over gravitational force. Time kinetics studies show a significant enhancement in ME-MION efficiency after binding with PMO implying the availability of large surface of the ME-MION. The coagulated particles (impurities) can be removed from PMO+ME-MIONby washing with mild detergent or cleaning solution. To our knowledge, this is the first report on surface water turbidity removal using protein-functionalized magnetic nanoparticle.

  • 49.
    Okoli, Chuka
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology. KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Boutonnet, Magali
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Mariey, Laurence
    Spectrochemistry, ENSICAEN, France.
    Järås, Sven
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Application of magnetic iron oxide nanoparticles prepared from microemulsions for protein purification2011In: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 86, no 11, p. 1386-1393Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Magnetic nanoparticles are of immense interest for their applications in biotechnology. This paper reports the synthesis of magnetic iron oxide nanoparticles from two different water-in-oil microemulsion systems (ME-MIONs), their characterization and also their use in purification of coagulant protein. RESULTS: ME-MIONs have demonstrated to be an efficient binder in the purification of Moringa oleifera protein when compared with the superparamagnetic iron oxide nanoparticles prepared from coprecipitation in aqueous media. The size and morphology of the ME-MIONs were studied by transmission electron microscopy (TEM) while the structural characteristics were studied by X-ray diffraction (XRD). The microemulsion magnetic iron oxide nanoparticles (ME 1-MION and ME 2-MION) obtained have a size range 7-10 nm. The protein and ME-MIONs interaction was investigated by Fourier transform infrared spectroscopy (FT-IR); the presence of three peaks at 2970, 2910 and 2870 cm(-1) respectively, confirms the binding of the protein. The purification and molecular weight of the coagulant protein was 6.5 kDa as analyzed by SDS-PAGE. CONCLUSION: The ME-MIONs have the advantage of being easily tailored in size, are highly efficient as well as magnetic, cost effective and versatile; they are, thus, very suitable for use in a novel purification technique for protein or biomolecules that possess similar characteristics to the Moringa oleifera coagulant protein.

  • 50.
    Okoli, Chuka
    et al.
    KTH, School of Biotechnology (BIO), Environmental Microbiology. KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Fornara, Andrea
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Qin, Jian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Dalhammar, Gunnel
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Characterization of Superparamagnetic Iron Oxide Nanoparticles and Its Application in Protein Purification2011In: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 11, no 11, p. 10201-10206Article in journal (Refereed)
    Abstract [en]

    The application of surface modified magnetic adsorbent particles in combination with magnetic separation techniques has received considerable awareness in recent years. There is a particular need in protein purification and analysis for specific, functional and generic methods of protein binding on solid supports. Nanoscale superparamagnetic iron oxide particles have been used to purify a natural coagulant protein extracted from Moringa oleiferaseeds. Spectrophotometric analysis of the coagulant protein was performed using synthetic clay solution as substrate. Protein binding with carboxyl and silica surface modified superparamagnetic iron oxide nanoparticles (SPION) were compared with the known carboxyl methyl cellulose (CMC) beads of ∼1 m. SPION modified with carboxyl surface showed higher binding capacity towards the coagulant protein compared to the CMC beads. The high surface area to volume ratio of the carboxyl-coated SPION resulted in high binding capacity and rapid adsorption kinetics of the crude protein extract. The purification and molecular weight of coagulant protein is analyzed by SDS-PAGE. This approach utilizes the most efficient, feasible and economical method of coagulant protein purification and it can also be applicable to other proteins that possess similar properties.

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