链霉菌WH63的抑藻效应

Inhibitory effect of Streptomyces WH63 on Microcystis aeruginosa

研究链霉菌WH63抑藻效应。以铜绿微囊藻作为受试对象,通过平板实验、液体发酵、链霉菌WH63发酵产物分析、藻毒素含量测定和水培青菜,探讨链霉菌WH63抑藻效应。结果发现,链霉菌WH63活菌和过滤除菌后的发酵液均有抑制铜绿微囊藻生长的能力,第4天时接种3%过滤除菌的链霉菌WH63发酵液抑藻率就达到了96.7%,且WH63菌株的发酵液具有很好的热稳定性,乙酸乙酯的萃取WH63菌株发酵液抑藻效果最好,其抑藻物质为脂溶性弱极性物质。进一步分析其第15天的抑藻水样,COD含量比正常生长的铜绿微囊藻下降了61.4%,BOD下降了13.4%,藻毒素含量比其低57.9%,继续培养到第40天时都没有回绿现象,且水样清澈。用杀藻后的水样直接浇灌青菜种子,观察种子萌发数,结果表明,处理后的水样发芽率为100%,发芽势、活力指数、茎长和幼苗鲜重比水对照分别提高10.2%、147%、121%和71.6%。实验表明,用链霉菌WH63抑藻后的水样具有很好的促植物生长和提高植物抗性的效果,为链霉菌以后运用到水培蔬菜抑藻剂的开发提供了一定的理论基础。

The inhibitory effect of Streptomyces WH63 on Microcystis aeruginosa was studied. A plating experiment,liquid fermentation,and water planting were used,and the fermentation products of Streptomyces WH63 and microcystin content were detected. The growth of M. aeruginosa was inhibited by a fermentation liquid that either contained live WH63 or was filtered to remove bacteria. The WH63 fermentation liquid had high thermal stability. The rate of algal inhibition reached 96. 7% after inoculating 3% filtered WH63 fermentation liquid on the4 th day. The inhibitory substance extracted from Streptomyces WH63 was fat-soluble with weak polarity and had the strongest algal-inhibitory effect when extracted by ethyl acetate. Further analysis of water samples inhibited by WH63 at the 15 th day revealed that chemical oxygen demand（ COD）,biological oxygen demand（ BOD）,and microcystin decreased by 61. 4%,13. 4%,and 57. 9%,respectively,compared with normal M. aeruginosa. The water sample remained clear on the 40 th day and did not regreen. The seed germination rate was observed after irrigation a water sample inhibited by WH63. The germination rate was still 100% after treatment and the germination potential,vigor index,stem length,and seedling fresh weight increased by 10. 2%,147%,121%,and71. 6%,respectively. These results suggested that water samples with Streptomyces WH63 have a potent effect on promoting plant growth and improving plant resistance,which provides a theoretical basis for the use of Streptomyces to develop hydroponic vegetable algicides.