[Isolation and activity of bacteria for the biodegradation of microcystins].

The abilities of bacterial communities, which collected from the sediment and surface water of Dianchi Lake, for the biodegradation of microcystins (MCs) were firstly investigated. It was shown that the biodegradation rates of both MC-RR and LR by bacteria in sediment were apparently higher than those by bacteria on surface water. Five strains of bacteria, which have the abilities in the biodegradation of MCs, from the sediment were isolated using the liquid and solid medium containing MC-RR and LR as the carbon and nitrogen sources, which was extracted and purified from the cells of cyanobacterial bloom. Among the bacteria isolated, bacterium D was found to have a strong ability in the biodegradation of MCs. Initial MC-RR and LR of 60.1 mg x L(-1) and 38.7 mg x L(-1) were completely removed in 3 days and the average biodegradation rates per day for MC-RR and LR were 20.0 mg x L(-1) and 12.9 mg x L(-1), respectively.