一株溶藻细菌的分离鉴定及溶藻效果

Isolation and Identification of an Algae-lysing Bacterium and Its Algicidal Effect

从太湖分离到一株溶藻细菌CA,该菌对铜绿微囊藻具有强烈的溶藻效果.通过形态学、生理生化特征及16SrDNA序列比对,鉴定该菌株属于水单胞菌属(Aquimonas sp.).将CA菌悬液与铜绿微囊藻共培养,10 d内铜绿微囊藻细胞降解率为100%,叶绿素a降解率为83.9%,且溶藻效果与菌悬液浓度呈正相关,与藻浓度呈负相关.CA菌体本身没有溶藻效果,但其无菌滤液可以溶藻,因此CA是通过释放物质来间接溶藻.在CA菌体的菌藻共培养液中添加少量的牛肉膏、葡萄糖或尿素,菌体显示出溶藻效果.本研究为菌株CA控制铜绿微囊藻水华提供了一种潜在的应用前景.

Water blooms caused by Microcystis aeruginosa broke out frequently all over the world,which caused serious environmental problems.In this study,an algae-lysing bacterium CA with a strong algicidal effect to M.aeruginosa was isolated from the Taihu Lake,China.Then CA was identified as Aquimonas sp.by morphological features,physiological and biochemical characteristics,as well as phylogenetic analysis of 16S rDNA sequences.The degradation rate of CA against M.aeruginosa cells and chlorophyll a were 100% and 83.9% within ten days,respectively.Algicidal effect of CA was positively correlated with the concentration of bacterial suspensions,while negatively correlated with algal concentration.The bacterial cell of CA had no algicidal effect,but their sterile filtrate could lyse M.aeruginosa significantly,indicating that CA lyse M.aeruginosa by an indirect way of excreting algae-lysing substance.The CA cell displayed algicidal effect when adding a small amount of beef extract,glucose or urea to liquid culture.These results indicated that strain CA had potential for controlling the bloom-forming cyanobacteria in freshwater ecosystems.