Isolation and identification of algicidal compound from Streptomyces and algicidal mechanism to Microcystis aeruginosa.

The biological control of cyanobacterial harmful algal blooms (cyanoHABs) is important to promote human health, environmental protection, and economic growth. Active algicidal compounds and algicidal mechanisms should be identified and investigated to control cyanoHABs. In this study, the algicidal actinobacterium Streptomyces sp. L74 was isolated from the soil of a nearby pond which located in the center lake of Guanghzou Higher Education Mega Center. Results showed that the algicidal activities of cyanoHABs are mainly achieved via an indirect attack by producing algicidal compounds. All active algicidal compounds are hydrophilic substances that are heat and pH stable. In the present study, an active compound (B3) was isolated and purified by high-performance liquid chromatography and identified as a type of triterpenoid saponin (2-hydroxy-12-oleanene-3, 28-O-D-glucopyranosyl) with a molecular formula of C42H70O13 as determined by infrared spectrometry, electrospray ionization mass spectrometry, and nuclear magnetic resonance. Active algicidal compounds from Streptomyces sp. L74 were shown to disrupt the antioxidant systems of Microcystis aeruginosa cells.

蓝藻有害藻华（cyanoHABs）的生物控制对促进人类健康、环境保护和经济增长具有重要意义。应识别和研究有效的杀藻化合物及杀藻机制以控制蓝藻有害藻华。在本研究中，从位于广州大学城中心湖附近池塘的土壤中分离出一株具有杀藻作用的放线菌Streptomyces sp. L74。结果表明，该菌对蓝藻有害藻华的杀藻活性主要是通过产生杀藻化合物进行间接攻击实现的。所有有效的杀藻化合物均为亲水物质，且对热和pH稳定。在本研究中，通过高效液相色谱法分离纯化出一种活性化合物（B3），经红外光谱、电喷雾电离质谱和核磁共振测定，其被鉴定为一种三萜皂苷（2 - 羟基 - 12 - 齐墩果烯 - 3, 28 - O - D - 吡喃葡萄糖苷），分子式为C42H70O13。来自Streptomyces sp. L74的活性杀藻化合物被证明可破坏铜绿微囊藻细胞的抗氧化系统。