Study On Isolation Of A Algae-lysing Bacteria And Its Effect On The Treatment Of Microcystis Aeruginosa

With the rapid development of the global economy,the widespread eutrophication of water is becoming more and more serious.Algae as an important primary productivity in aquatic ecosystems,the frequent outbreak of algal blooms has become a serious hazard to ecological balance,affecting human production and life Environmental pollution problems [1].But also at this stage a greater impact,the scope of hazards throughout the world of every waters of the world[2].Therefore,the algae blooms and the disaster caused by the development of control technology research is extremely urgent.In 2015,China’s 115 lakes,in the eutrophic state of the lake has 90,accounting for up to 78.3%[3],not only seriously undermined the ecological balance of water,while the water eutrophic state,the outbreak of algal blooms Algae metabolism produced by the rapid increase in algal toxins,to human health and normal production and life a huge threat[4].Algae bacteria and other microorganisms is an important part of the aquatic ecosystem,but also has a natural easy to get,economical,environmentally friendly,the role of obvious features in the control of algae growth,to maintain its balance plays an important role[5].But also by more and more attention [6-7].It is important to study the mechanism of algae algae removal and algae algae,and to develop algae microbial agents,which is of great significance for the prevention and control of eutrophic water bodies[8].Seven strains of bacteria（No.S1 ～ S7）were isolated and purified from the local eutrophic water by natural induction.Three of them（S4,S₅,S7）were able to make the microcystisite yellowish,and finally,Preferably,the most significant of the algal’s yellowing of the S₅ bacteria was the strain of this study.The preliminary identification and toxicity test of S₅ strain were carried out,and then its effect on the microcystis aeruginosa was verified,and the algae-killing effect was verified.Then the mechanism of the algae was explored,and finally it was applied to the natural rich water.The experimental data are summarized ingeneral,and the following conclusions are drawn.1.The strain S₅ was identified by bacterial morphological observation,dyeing test and physiological and biochemical test.According to the "Common Bacteria System Identification Manual" and "Berger Bacteria Identification Manual",the S₅ strain was identified as Bacillus,To be studied at the molecular level.2.So that the algae-resistant bacteria S₅ on the blue zebrafish,its ecological toxicological safety testing,testing confirmed that algae-resistant bacteria S₅ on the role of the growth of no effect,and no genetic toxicity.3.The results showed that compared with the control group,9%,6%,9% and 12%of the algae bacteria were added to the copper microcystis solution.The number of algae cells and chlorophyll a were decreased by 82.65% and 74.71%,respectively.On the 9th day,the two groups decreased by 82.56% and 77.14% respectively.The effect of S₅ bacteria on the number of algal cells and the content of chlorophyll a was about the same.The higher the concentration of bacteria was,the more obvious the dissolution effect of Microcystis aeruginosa.However,taking into account the operation steps and costs,it is recommended that the actual treatment,so that the amount of sewage broth solution of copper green microcystis volume of 9%,and the first 7 days to achieve significant algae removal effect.4.Respectively,to the microcystis aeruginosa by adding different ways to deal with the bacteria suspension,high temperature treatment bacteria suspension,supernatant,high temperature treatment supernatant,bacterial liquid medium and S₅ bacteria solution,explore the S₅ bacteria dissolved Algae,experiments show that S₅ is through the release of thermally stable extracellular substances to indirect algae.And then through the supernatant color reaction to the algae-lysing activity of the study,the results show that S₅ release of extracellular substances for the heat of the saccharide substances.5.Adding 9%（v/v）of S₅ bacteria to the natural collected water in the eutrophic state.After 15 days,the algae community structure was found.After adding S₅,the total density of algae increased from 1.75×106 /L1.09×106 /L,algae removal rate of62.29%.Further analysis of the composition of algae: the dominant species of thewater species from the initial single and absolute advantage of the Scenedesmus obliquus into the four litmus litter,Scenedesmus obliquus and fixed microcystis common constitute the dominant species,the three accounted for the total amount of algae 56.61%,while the diversity index and evenness index showed an increasing trend,while the two indexes in the reaction pool without bacteria were decreased,and the dominant species were unchanged.