Metabolic Characteristics And Effects On Microcystis Growth Of Attached Bacteria Of Microcystis Bloom

In natural water bodies,Microcystis aeruginosa was wrapped with gel,and a lot of attached bacteria were adhered to the gel.On the one hand,Microcystis aeruginosa would provide large amounts of organic substances for the growth and reproduction of attached bacteria in the process of breeding and decay of algae;on the other hand,the attached bacteria would decompose or transformate the organic matter to affect the growth of Microcystis in turn,or provided nutrients and necessary growth factors for the growth of Microcystis,or restrained the growth of the Microcystis directly or indirectly,even cracked Microcystis cells in the process of growth of attached bacteria.To study the effect of attached bacterias on the microenvironment of Microcystis in the bloom,thirty-four strains of attached bacteria were isolated from different water blooms,and their casease activity?ammonia nitrogen elimination ability?nitrate reductase activity?alkaline phosphatase activity and esterase activity were studied.To evaluate the effects of the bacteria on growth of Microcystis,group millirod was selected as the material,co-cultures of each isolate mixed with the Microcystis were tested.The results of nitrogen metabolism showed that 13 strains could hydrolyze casein,5 strains had strong ability to removal ammonia,1 strain had a strong nitrate reductase activity.4 strains had phosphatase activity,11 strains had esterase activity.The results of the co-cultures of bacteria and Microcystin were showed:7 strains of bacteria promoted the growth of algae obviously,occupying 20%of the total strains;2 strains displayed obvious inhibitory to the growth of algae,occupying 6%of the total strains.Other 25 strains had no obvious effect on the growth of Microcystin algae.Two strains(Q-4?Q-14)accelerating the growth of algae and two strains(8-5?CH-3)inhibiting the growth of Microcystis were identified as Bacillus firmus?Aeromonas aquariorum?Acidovorax delafieldii?Bacillus cereus according to the 16S rDNA sequence homology comparison and phylogenetic analysis.