抗真菌土壤放线菌的筛选鉴定、发酵培养基优化及发酵液稳定性研究

以6种农作物病原真菌为指示菌,从湖北省神龙架地区的土壤中筛选得到1株抗真菌放线菌,命名为ⅡB21.经过形态观察、生理生化分析和16 S rDNA序列同源性分析,初步鉴定该菌株属于链霉菌属(Streptomyces).通过单因素和正交试验确定优化后的发酵培养基配方为蔗糖10.00 g/L,牛肉膏4.00 g/L,K2HPO43.00 g/L,MgSO4 0.75 g/L,KH2PO4 1.00 g/L.发酵液稳定性试验表明,发酵液在30℃下达到最大抑菌活性,抑菌圈直径为41.16 mm,在4～60℃下具有较好的热稳定性,其抑菌圈直径均为最大抑菌活性的72.10％以上;发酵液在pH 3.0～10.0具有较好的酸碱稳定性,其抑菌圈直径均在最大抑菌活性的74.95％以上;发酵液中抑菌活性物质在紫外光照射下具有较好的稳定性.

Isolation and Identification of An Antifungal Actinomycete, and Study on the Optimum Medium and Fermentation Broths Stability

Take six pathogenic fungi of crop as indicators,an antifungal actinomycete,named as ⅡB21,was selected from the soil collected from Shenglongjia in Hubei Province.It was identified as Strepomyces sp.by standard morphological,physiological properties and 16 S rDNA analysis.Through single factor experiment and orthogonal tests,the optimum fermentation medium was determined as sucrose 10.00 g,beef extract 4.00 g,K2HP04 3.00 g,MgSO4 0.75 g,KH2PO4 1.00 g.The experiments showed that the stability of the fermentation broth was up to the best antimicrobial activity at 30 ℃ as the inhibition diameter was 41.16 mm,and was fairly stable at 4～60 ℃ while the inhibition diameters were above 72.10% of the best antimicrobial activity;and was fairly stable at pH 3.0～10.0 when the inhibition diameters were above 74.95% of the best antimicrobial activity;antimicrobial activity substance of the fermentation broth was fairly stable at UV.