Studies On The Ecophysiological Effects And Mechanisms Of Algae-lysing Bacteria Agaist The Algae

Nowadays, eutrophication and massive accumulations of planktonic microalgae as algal blooms in waterbodies have caused serious environmental problems. So it is very important to find an effective method for controlling the growth of the bloom-forming algae. Measures for controlling such kind of algae include physical, chemic and biologic means, but the former two may damage the aquatic environment and require high-energy inputs. The alternative approach for the elimination of nuisance algae involves the application of algae-lysing bacteria. The lytic bacteria, which are nontoxic to other organism and most of which are isolated from the lake in situ, may be potential microbial algaecides. In the initial stages of the water blooms, they are able to restrain the biomass or multiplication of the bloom-forming algae in a short time. In this study, we isolated four bacteria (Pseudomonas mendocina DC10, Staphylococcus sp. DC21, Bacillus cereus DC22 and Flavobacterium branchiophila DC-P) and investigated their lytic abilities and mechanisms.1. Isolation, identification and Toxicity testing of the algae-lysing bacteria.1) Among 58 bacteria isolated from Lake Dianchi, strain DC10, DC21, DC22 and DC-P showed strong lytic activities, thus, they were selected to be as research materials.2) On the basis of biochemical and morphological test, strain DC10, DC21, DC22 and DC-P were identified respectively as Pseudomonas mendocina, Staphylococcus sp., Bacillus cereus and Flavobacterium branchiophila by China Center Type Culture Collection (CCTCC).3) It was shown that strain DC21 had strong adverse effect on kunming mice by toxicity testing, but no adverse effects were detected when strain DC10, DC22 and...