解淀粉芽胞杆菌PC2产抑菌物质培养基及发酵条件优化

【目的】优化解淀粉芽胞杆菌PC2产抑菌活性物质发酵培养基及发酵条件。【方法】以马铃薯葡萄糖液体培养基为基础,依据发酵液对金黄色葡萄球菌抑菌圈的单因素试验结果,采用Box-Behnken响应面法优化发酵培养基,二次通用旋转组合设计,频率分析法优化发酵条件。【结果】影响发酵液抑菌活性的培养基主要组分为马铃薯、蔗糖和L-谷氨酸钠,最优发酵培养基配方为:马铃薯188.0 g/L,蔗糖22.0 g/L,L-谷氨酸钠1.80 g/L,培养基成本为0.81元/L;最佳发酵条件为:接种量6%、发酵温度30°C、装液量40 mL/250 mL、摇床转速185 r/min、发酵时间24 h、初始pH 7.0。优化后发酵液对金黄色葡萄球菌抑菌圈直径为30.82 mm,较优化前的18.22 mm增加了12.60 mm。【结论】优化后的培养基和发酵条件提高了解淀粉芽胞杆菌PC2发酵液的抑菌活性,为该菌株的工业化生产应用提供了依据。

Optimization of fermentation medium and conditions for antimicrobial substances production by Bacillus amyloliquefaciens PC2

Objective] To improve antimicrobial activity of Bacillus amyloliquefaciens strain PC2, the medium composition and fermentation conditions were optimized in our work. Methods] Single factor experiments were carried to evaluate the effect of alternative constitutes for PDB medium on inhibition zone diameter against Staphylococcus aureus, Box-Behnken response surface methodology was conducted to obtain the optimal composition of the crucial medium factors. The optimal fermentation conditions were obtained through frequency analysis based on quadratic general rotary composite design. Results] The optimal medium compositions were (g/L): potato 188.0, sucrose 22.0, L-monosodium glutamate 1.80, and the media cost was 0.81 RMB per litre. The optimal fermentation conditions were as follows: inoculation amount 6%, culture temperature 30 °C, liquid volume 40 mL/250 mL, rotation speed 185 r/min, initial pH value 7.0, and fermentation for 24 h. Appling optimal medium and culture conditions, the inhibition zone diameter of free-cell fermentation broth on Staphylococcus aureus reached to 30.82 mm, increased by 12.60 mm compared with the original conditions. Conclusion] The present study provides a cost-effective medium and fermentation conditions for further study on large scale fermentation for antimicrobial substances production.