产表面活性素野生菌株的筛选、鉴定及其发酵条件研究

Study of Screening,Identification and Fermentation Conditions of Wild Strains Producing Surfactin

通过血平板法、排油性试验、抑菌试验结合高效液相色谱法从菜园土壤中分离筛选一株产表面活性素(surfactin)的野生型菌株。通过形态特征、生理生化试验及16S rRNA序列分析对其进行鉴定,并研究其发酵条件。结果表明,菌株K-19产表面活性素较高,经鉴定,K-19为贝莱斯芽孢杆菌(Bacillus velezensis)。最有利于产生surfactin的发酵培养基成分为豆粕40 g/L、葡萄糖9 g/L、MgSO_(4)0.2 g/L、MnSO_(4)2.5 mg/L、FeSO_(4)0.8 mg/L、L-谷氨酸3 mg/L;在pH=7、温度35℃、转速160 r/min的条件下培养42 h,surfactin的产量可达1.40 g/L。本试验为大规模生产surfactin奠定了基础。

Wild strain with high surfactin yield was isolated from vegetable garden soil by using blood-agar method,oil-spreading test,inhibitory test and high performance liquid chromatography(HPLC)method.It was identified by morphological characteristics,physiological and biochemical test and phylogenetic analysis of 16 S rRNA sequence,and the fermentation conditions were studied.The results showed that the strain K-19 was identified as Bacillus velezensis produced higher surfactin.The optimum medium for production of surfactin was soybean meal 40 g/L,Glucose 9 g/L,MgSO_(4)0.2 g/L,MnSO_(4)2.5 mg/L,FeSO_(4)0.8 mg/L and L-glutamic acid 3 mg/L.The surfactin yield reached 1.40 g/L after cultured for 42 h under the conditions of pH 7,35℃and 160 r/min.This experiment laid a foundation for large-scale production of surfactin.