放线菌JXJ-0110对铜绿微囊藻的溶藻活性

Algae-lysing activity of Microcystis aeruginosa by actinomyces JXJ-0110

为明确放线菌JXJ-0110及其代谢产物对铜绿微囊藻的溶藻活性和藻细胞生长的影响,以及菌株的分类地位,采用热乙醇法测定藻细胞叶绿素a含量,在光学显微镜下计数藻细胞数目,并利用16S rDNA的基因序列分析确定其所在属.结果表明：放线菌JXJ-0110的菌丝体具有很强的溶藻活性,且呈剂量关系.发酵上清液也具有很强的溶藻活性,藻液（1 ml 1.0×10^7个）中加入2％（体积比）的发酵上清液,3d后叶绿素a的去除率达到88.4％.溶藻活性成分主要为胞外水溶性物质和胞内脂溶性物质.发酵上清液的溶藻活性对高温、pH值和254 nm的紫外线处理均具有较好的稳定性,90℃水浴处理发酵上清液2h,叶绿素a的去除率超过82％；pH 6 ～ 10处理发酵上清液2h,叶绿素a的去除率超过82％；紫外线254 nm下照射发酵上清液2h,叶绿素a的去除率为86.4％.16S rDNA基因序列发育分析表明,菌株JXJ-0110属于链霉菌属成员,与Streptomyces shenzhenensis 172115T的序列相似性最高（99.06％）.放线菌JXJ-0110及其代谢产物在铜绿微囊藻水华防治方面具有潜在应用价值.

The algae-lysing activities of actinomyces JXJ-0110 and its metabolites on Microcystis aeruginosa were studiedby measuring chlorophyll a contents using hot-ethanol extraction method, and the taxonomic status of JXJ-0110 was defined by a-nalysis of 16S rDNA gene sequences. The mycelia of JXJ-0110 showed strong algae-lysing activities which was dose-related, andthe removal rates of chlorophyll a in M. aeruginosa increased from 60.5% to 91.2% when mycelia （fresh weight） increased from0.5 g to 2.0 g. The fermentation supernatant of the strain also exhibited strong algae-lysing activities,88.4% of chlorophyll a be-ing wiped off three days after 2% （V/ V） fermentation supernatant addition, and the biomass of algae being restrained to a verylow level for more than forty days. The algae-lysing components were mainly extracellular water-soluble substances and intracellu-lar fat-soluble substances. The algae-lysing activity offermentation supernatant was independant of hightemperature, pH changes and ultraviolet radiation at 254 nm,with the removal rates of chlorophyll a being kept stable over82%. 16S rDNA sequencing revealed that strain JXJ-0110was a member Streptomyces, and its sequence shared 99.06%similarity with Streptomyces shenzhenensis 172115T.