Studies Of Separation And Appraisal Of Algae Lysing Bacteria And Its Dissolution Effect To Microcystis Aeruginosa

With the improvement of the industrialization,the development of city and the increase of population,human activities have become increasingly frequent and profound influence on water environment.At present,China has more than 66%lakes and reservoirs in different degrees of eutrophication pollution,not only destroyed the balance of water ecosystem,but Microcystis in bloom waters produced a lot of algal toxins and other metabolites would bring negative influence on public health,livestock and water supply.In recent years,the north lake and reservoir eutrophication gradually emerged,the nitrogen,phosphorus content in water have the trend of overproof.Accumulation of nitrogen,phosphorus in water reach a certain number will cause water eutrophication,even cause harmful algal blooms,to explore effective ways to surppress the algal bloom outbreaks is extremely urgent.Useing the physical,chemical and other biological methods to control algal blooms is not ideal,the algae lysing bacteria algae removal has become the hotspot of biological control of algae.This paper base on the common algae Microcystis who lead to algal blooms as the object of study,using the method of natural induced,isolated algae lysing bacteria from the local eutrophication water,using the blue zebrafish as test object,the algae lysing bacteria ecotoxicological safety testing.The algae lysing bacteria was identified by physiological and biochemical combined with 16S rDNA,detaily studied the effects and mechanism of algae solution of algae lysing bacteria,and preliminarily identified the algicidal substance composition.The results were as follows:(1)From the local eutrophication water separated and purified five bacterias,among them the bacterias AO with dissolution of Microcystis aeruginosa.And the algae lysing bacteria ecotoxicological safety testing show that algicidal bacteria AO have no effect on zebrafish growth.(2)Combined with the physiological and biochemical characteristics and 16S rDNA sequencing results.according to the "Common bacterial system identification manual" and "Berger bacterial identification manual",identify the bacteria AO as Bacillus megaterium,the homology of the 16S rDNA sequence is 99.5%.The bacterias A0 has preserved in China Center for Type Culture Collection in September 27,2013,NO.CCTCC NO:M 2013452.(3)The research on the effect of different dosage of algae lysing bacteria Bacillus megaterium show that,the effect on Microcystis aeruginosa algae number and cell chlorophyll a content of bacteria in different dosage is significantly.Compared with the control group,the 7.5%treatment groups sixth days of algal cell number reduce 66.7%,the chlorophyll a content reduce 35.2%,the 10%treatment groups sixth days of algal cell number reduce 72.3%,the chlorophyll a content reduce 51.9%.Complexing the analysis results of the text and the cost,determining the best dosage for Bacillus megaterium produced dissolution of Microcystis aeruginosa is 7.5%,the shortest co cultured days are 6 days.(4)Studing the algicidal mechanism and algicidal substances of algicidal bacteria Bacillus megaterium,the results showed that Bacillus megaterium through release thermal stability extracellular substance to indirect algicidal,and the extracellular substance is polysaccharide.