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| Identification and activity of a bacterial strain for the biodegradation of microcystins |
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Abstract A microcystin-degrading bacterial strain M9 isolated from Chaohu Lake was identified by physiological- biochemical characteristics and homology analysis of 16S rDNA gene sequence. BLAST sequence analysis showed that it had a 99% similarity to kurthia gibsonii. The effects of pH, additional carbon and nitrogen sources, and metal ions on the biodegradation activity of microcystins (MCs) by strain M9 were investigated. pH7.0 was the best value for the biodegradation of MCs by strain M9.Compared with glucose and glycerol, ethanol was found to be a better carbon source for the biodegradation of MCs by strain M9, and the biodegradation rates of microcystin-RR(MC-RR) and microcystin- LR(MC-LR) in 48h were 70.0% and 81.4%, respectively. (NH4)2SO4 was the best nitrogen source for strain M9 comparing with other nitrogen sources, and the biodegradation rates of MC-RR and MC-LR in 48h were 70.4% and 80.9%, respectively. It was shown that the biodegradation of MCs could be increased with Cu2+, Zn2+ and Mn2+, and the biodegradation rates of MC-RR and MC-LR in 48h were higher than 85% and 93%, respectively. However, obvious acceleration with Fe3+ and Mg2+ for the biodegradation of MCs was not observed.
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Received: 14 May 2010
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