The Feasibility Study On The Use Of Cyanobacteria Of Taihu Lake

Cyanobacteria is a kind of prokaryote with a long history of evolution, Gram-negative, non-flagellar, including chlorophyll a, no chloroplast, it can photosynthesis with the production of oxygen. In recent years, the blue algae frequently outbreaks in Taihu Lake, a large number of cyanobacteria had been raised, but it's difficult to dispose them. In this paper, multi-channel was carried to study the feasibility of the use of it, trying to find an effective way to make them helpful.Component analysis of the algae showed its high protein content, reaching 40.45 percent, the microcystin concentration is 2 mg/g. Using 1% algae to cultivate Saccharomyces cerevisiae, the biomass was only 1.5g/L after 26h, the conversion rate of cyanobacteria was only 16%, the microcystin didn't degradated, the microcystin concentration of yeast is 390μg/kg, it showed non-feasibility to use the cyanobacteria this way.We screened a strain of L3 with significant ability to degrade microcystin from the sediment of Taihu Lake, identification showed it belongs to Enterobacter. Under suitable condition, after 72h fermentation, it can degradate MC-RR and MC-LR with the initial concentration of 50 mg?L-1 to the rate of 73.5%, 72.8% respectively, and the degradation occurred extracellularly. UV-nitrosoguanidine mutagenesis was carried to L3, we gained a high-degradating mutant L3-s8, its degradation rate of microcystin reached to 91.5%, increased 24.5%, and spontaneous reverse mutation hadn't be found after 10 run of propagation.Taking cyanobacteria and rice straw as materials of solid fermentation, we found fungal M-1, M-2 after non-sterilized natural fermentation,they belonged to Mucor and Trichoderma respectively. We inoculated L3-s8 with M-1, M-2,the degradation rate of microcystin reached to 40.5%, the fermented materials meet the criteria of organic fertilizer well, but trace microcystin still residued, it showed feasibility to use cyanobacteria this way.