地衣芽孢杆菌XY—2的筛选及其培养基的优化

Screening and Optimization of Conditions of Bacillus Iicheniformis XY-2

从土壤中筛选出3株具有较强抑菌活性的菌株,其中XY-2菌株对金黄色葡萄球菌、枯草芽孢杆菌、灰霉葡萄孢菌、变形链球菌和大肠杆菌的抑制作用最强。根据对XY-2菌株形态特征、培养特征、生理生化特征的分析,初步鉴定为地衣芽孢杆菌。最后通过正交实验对地衣芽孢杆菌XY-2的发酵培养基成分配比进行了选择和优化,为以后工业化生产提供依据。结果表明当培养基质量浓度配比为：ρ（玉米淀粉）20 g/L、ρ（豆饼粉）90 g/L、ρ（玉米浆）7 g/L时菌体的培养效果最好。在最佳配比下培养基中活菌浓度可以达到9.67×10~8 cfu/mL。

Three strains of bacteria,which had a strong antibacterial activity,were selected from the soil.The strain of XY- 2 had the strongest inhibition against Staphylococcus aureus,Bacillus subtilis,Botrytis cinerea,Streptococcus mutans,E. coli.According to the analysis of morphological characteristics,training characteristics,physiological,and biochemical characteristics of XY-2,it was identified as Bacillus licheniformis.The compositions of fermentation medium of XY-2 were optimized by the orthogonal test.The results show that the optimized medium are as follows：ρ（corn starch） 20 g/L,ρ（soybean powder） 90 g/L,ρ（corn steep liquor） 7 g/L.Under these conditions,the concentration of viable cells in fermentation broth can reach9.67×10~8 cfu/mL.