Simple and rapid methods for purification and characterization of active coagulants from the seeds of Vigna unguiculata and Parkinsonia aculeata
2007 (English)In: Environmental technology, ISSN 0959-3330, Vol. 28, no 6, 671-681 p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2007. Vol. 28, no 6, 671-681 p.
coagulation activity; local seeds; proteins; turbidity removal; extraction
IdentifiersURN: urn:nbn:se:kth:diva-8565DOI: 10.1080/09593332808618827ISI: 000247827800008ScopusID: 2-s2.0-34447125279OAI: oai:DiVA.org:kth-8565DiVA: diva2:13922
QC 201008252008-06-022008-06-022010-08-25Bibliographically approved