溶藻细菌MS7的分类鉴定及其溶藻活性的初步研究

采用形态学、生理生化指标和16SrRNA基因序列同源性分析的方法,对菌株MS7进行鉴定,并通过溶藻试验测定该菌株对铜绿微囊藻(Microcystis aeruginosa)的溶藻活性和溶藻方式。结果表明,MS7菌株为苏云金芽孢杆菌(Bacillus thuringiensis),对铜绿微囊藻具有高效溶藻效果,当菌浓度为108cells/mL,初始藻液叶绿素a浓度为0.7mg/L时,48h溶藻率达到91%。主要通过分泌胞外物质的间接方式溶藻,溶藻物质属于具有很强的热稳定性的非蛋白质类物质。

IDENTIFICATION OF AN ALGICIDAL BACTERIA MS7 AND PRIMARY STUDY ON ITS ALGICIDAL ACTIVITY

An algicidal bacteria MS7 was identified based on morphology, physiology, and 16S rRNA gene sequencing. The strain is Gram-positive, rod in shape, containing spores and parasporal crystal. Phylogenetic analysis based on 16S rRNA gene homology showed that the strain was closely related to the member of Bacillus thuringiensis AM778995.1, with which they shared 100% similarity. By VITEK 2 Compact automatic microbial analysis system tests, the strain MS7 identified as B. thuringiensis. The algae-lysing effect and algicidal mechanism were investigated. When the MS7 density was 10⁸ cells/ml and the initial concentration of Chlorophyll a was 0.7mg/L, the removal rate reached 91% after 48 hours. An extracellular substance produced by MS7 strain had algae-lysing ability, and it was identified as a therm-stable, non-protein substance. These results indicate that the strain MS7 is potential agents for the control of harmful algal blooms.