A strain of actinomycete JXJ 0071 was isolated from soil of the Lushan Mountain.Activities of its spores, mycelia and metabolites lysing Microcystis aeruginosa, stability of the active components of the activities and its taxonomic status were studied.Both spores and mycelia of actinomycete JXJ 0071 reduced the density of M.aeruginosa remarkably.Metabolites of the strain showed a very strong activity lysing M.aeruginosa, and 98％ alga cells perished three days after addition of fermentation supernatant 2％ in volume into the culture ( 1.0 × 107 mL-1 ) of M.aeruginosa.The alga-lysing active components were mainly water-soluble extracellular products, which remained quite stable regardless of exposure to high temperature, pH and ultraviolet radiation.The fermentation liquid stir showed a high alga-lysing rate, over 95％ after being incubated under 60 ℃ for two hours, over 93.8％ at pH 7 -9, and 85.7％ after exposure to 254 nm ultraviolet radiation for 2 hours.Based on 16S rRNA sequences, strain JXJ 0071 was identified to be of the genus of Streptomyces,being as high as 99％ similar to Streptomyces rectiviolaceus in 16S rRNA gene sequence.However, differences were found between JXJ 0071 and S.rectiviolaceus in physiological and biochemical properties.Further studies should be carried out to determine its exact taxonomic status at the species level.%从庐山土样中分离得到一株放线菌JXJ0071,研究了该菌的孢子、菌丝体和代谢产物对铜绿微囊藻(Microcystis aeruginosa)的溶藻活性以及溶藻活性成分的稳定性,并对其分类地位进行鉴定.结果表明,放线菌JXJ0071的孢子和菌丝体均能使铜绿微囊藻细胞密度显著降低.该菌代谢产物对铜绿微囊藻具有很强的溶藻活性,在藻密度为1.O×107mL-1的藻液中加入体积分数ψ为2%的该菌发酵上清液,3 d后溶藻效率达98%.溶藻活性成分主要来自水溶性胞外产物,其对高温、pH和紫外线处理均具有较好的稳定性.以60℃以下的温度处理发酵液2h,溶藻活性成分的溶藻效率基本不变,保持在95%以上;pH 7.0～9.0条件下,其溶藻效率仍很高,在93.8%以上;经波长为254 am的紫外线照射2 h,其溶藻效率仍达85.7%.基于16S rRNA基因序列的系统发育分析表明,该菌株属链霉菌属,与Streptomyces rectiviolaceus的序列相似性达99%,但JXJ0071与S.rectiviolaceus的部分生理生化特性有所不同,需要进一步的实验数据确定其种一级分类学单元.
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