Endre søk
Begrens søket
1 - 8 of 8
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Andersson, Sofia
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Characterization of Bacterial Biofilms for Wastewater Treatment2009Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Research performed at the Division of Environmental Microbiology has over the last years resulted in the isolation of possible bacterial key-organisms with efficient nutrient removal properties (Comamonas denitrificans, Brachymonas denitrificans, Aeromonas hydrophila). Effective use of these organisms for enhanced nutrient removal in wastewater treatment applications requires the strains to be retained, to proliferate and to maintain biological activity within theprocess. This can be achieved by immobilization of the organisms using an appropriate system.Two putative immobilization systems, agar entrapment and biofilm formation, wereassessed. Surface attached biofilm growth provided better results with respect to cell retention,proliferation and microbial activity than immobilization in agar beads. Thus, biofilm physiology was further characterized using simplified systems of single, dual or multi strain bacterial consortia containing the key-organisms as well as other wastewater treatment isolates. Mechanisms for initial adherence, biofilm formation over time, dynamics and characteristics of extracellular polymeric substances (EPS) and exopolysaccharides, nutrient removal activity as well as the effect of bacterial interactions were investigated. The results showed that all theassessed bacterial strains could form single strain biofilm providing that a suitable nutrientsupply was given. Production of EPS was found to be critical for biofilm development and both EPS and polysaccharide residue composition varied with bacterial strain, culture conditions and biofilm age. Denitrification and phosphorus removal activity of the keyorganisms was maintained in biofilm growth. Co-culturing of two or more strains resulted in both synergistic and antagonistic effects on biofilm formation as well as the microbial activitywithin the biofilm. Bacterial interactions also induced the synthesis of new polysaccharideswhich were not produced in pure strain biofilms.The complexity of single and mixed strain biofilm development and the implications of interactions on biofilm performance were underlined in this study. The data presented can be useful for modeling of biofilm systems, serve as a tool for selection of bacterial strain combinations to use for bioaugmentation/bioremediation or provide a base for further experiment design.

  • 2.
    Andersson, Sofia
    et al.
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi (stängd september 2009).
    Dalhammar, Gunnel
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi (stängd september 2009).
    Bioaugmentation for enhanced denitrification in a labscale treatment system2006Inngår i: Proceedings of the Second IASTED International Conference on Advanced Technology in the Environmental Field / [ed] Ubertini, L, ACTA Press, 2006, s. 63-67Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The effect of bioaugmentation was investigated in a predenitrification lab-scale wastewater treatment system. The aim was to investigate the difference between two approaches to bioaugmentation: one in which suspended overnight culture was used as inoculum and another where bacteria immobilized in 1% agar beads were used. Pure cultures of the denitrifying bacteria Comamonas denitrificans ATCC 700936T were used in the experiments. The effect of bioaugmentation on the system was monitored using fluorescent in situ hybridization (FISH) and denitrification activity tests. The bioaugmentation with suspended bacteria showed a rapid initial (4 days) increase in denitrification activity. After 8 days the activity declined to the level of the reference system and cells of C. denitrificans were no longer detectable. Augmentation with agar-embedded bacteria resulted in a small increase in activity and very few bacteria of C. denitrificans could be observed.

  • 3.
    Andersson, Sofia
    et al.
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Dalhammar, Gunnel
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Kuttuva Rajarao, Gunaratna
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Influence of microbial interactions and EPS/polysaccharide composition on nutrient removal activity in biofilms formed by strains found in wastewater treatment systems2011Inngår i: Microbiology Research, ISSN 0944-5013, E-ISSN 1618-0623, Vol. 166, nr 6, s. 449-457Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 4.
    Andersson, Sofia
    et al.
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Dalhammar, Gunnel
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Land, Carl Johan
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Kuttuva Rajarao, Gunaratna
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Biological nutrient removal by individual and mixed strain biofilmsManuskript (Annet vitenskapelig)
  • 5.
    Andersson, Sofia
    et al.
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Dalhammar, Gunnel
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Land, Carl Johan
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Kuttuva Rajarao, Gunaratna
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Characterization of extracellular polymeric substances from denitrifying organism Comamonas denitrificans2009Inngår i: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 82, nr 3, s. 535-543Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 6.
    Andersson, Sofia
    et al.
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Dalhammar, Gunnel
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Rajarao, Gunaratna Kuttuva
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Persistence and competition of denitrifying biofilms subjected to a natural wastewater floraManuskript (Annet vitenskapelig)
  • 7.
    Andersson, Sofia
    et al.
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Kuttuva Rajarao, Gunaratna
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Land, Carl Johan
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Dalhammar, Gunnel
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Biofilm formation and interactions of bacterial strains found in wastewater treatment systems2008Inngår i: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 283, nr 1, s. 83-90Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 8.
    Andersson, Sofia
    et al.
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Nilsson, Mirja
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Dalhammar, Gunnel
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Kuttuva Rajarao, Gunaratna
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Assessment of carrier materials for biofilm formation and denitrification2008Inngår i: Vatten, ISSN 0042-2886, Vol. 64, s. 201-207Artikkel i tidsskrift (Fagfellevurdert)
1 - 8 of 8
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf