一株抗多种水产病原菌放线菌的鉴定、发酵优化及其应用

Identification,fermental optimization and exploratory development of an actinomycete strain against diverse aquatic zymad

对一株抗多种水产病原菌的海洋放线菌进行细胞壁化学组分和16S rDNA序列分析,初步鉴定为弗氏链霉菌(Streptomyces fradiae)。通过正交试验确定其最佳发酵培养基为:葡萄糖1.5%、牛肉膏2%、海盐1.5%、MgSO4.7H2O0.05%、K2HPO40.05%、CaCO30.1%。最佳发酵条件为:温度33℃、初始pH6.0、接种量10%、种子液菌龄48h。生物活性检测显示原始发酵液的生物效价相当于硫酸卡那霉素为550.81μg/mL,对嗜水气单胞菌的MIC值和MBC值分别为13.67μg/mL和27.35μg/mL。对由嗜水气单胞菌引起的鱼病的最佳治疗剂量为3050μg/(kg.d),且无急性毒性。通过稳定性试验,发酵液中的抗菌活性成分对热、pH、光和贮藏时间都很稳定。

A marine actinomycete strain having antibacterial activity to aquatic pathogens was initially identified as Streptomyces fradiae by cytoderm chemi-component and 16S rDNA sequence analysis. The optimal fermentation conditions were as follows glucose 1.5% , beef extract 2% , sea salt l. 5% , K2HPO4 0.05% , CaCO3 0. 1% , MgSO4·7H2O 0.05% , temperature 33℃, primary pH 6.0, inoculum 10% , strain age 48h by orthogonal design. It was ascertained the valence of primary broth was as same as Kanamycin sulfate which was 550.81 μg/mL by bioactivity detection. Its MIC and MBC to Aeromonas hydrophila was respectively 13.67μg/mL and 27.35 μg/mL. The optimal therapeutic dosage was 3 050 μg/（kg·d） to the fish illness resulted from Aeromonas hydrophila. The antibiotic compound in broth was stable to heat, pH, light and storage time by stability test.