鱼类肠道益生地衣芽孢杆菌FA6发酵工艺的响应面法优化

OPTIMIZATION OF FERMENTATION MEDIUM AND CONDITIONS OF FISH INTESTINAL PROBIOTIC BACILLUS LICHENIFORMIS FA6 BY RESPONSE SURFACE METHODOLOGY

研究以地衣芽孢杆菌FA6活菌数为指标,采用单因素实验和响应面法实验优化了地衣芽孢杆菌FA6发酵培养基和发酵条件,获得了地衣芽孢杆菌FA6最佳发酵培养基:70 g/L可溶性淀粉、40 g/L酪蛋白胨、2 g/L K2HPO4、1 g/L KH_(2)PO_(4)、2 g/L Na_(2)HPO_(4)、2 g/L MgSO_(4)和8 g/L NaCl;以及最佳发酵条件:初始pH 7.0、接种量1%、发酵温度28.8℃、发酵时间31h、装液量50 mL/250 mL和转速160 r/min。在此发酵培养基和发酵条件下,地衣芽孢杆菌FA6活菌数为7.97×10^(9)CFU/mL,较优化前提高了8.1倍。最佳发酵工艺的获得,将能够为鱼源芽孢杆菌的高密度生产,产业化应用提供基础。

In recent years,Bacillus used in aquaculture has attracted much attention as a microbial candidate to maintain the health and well-being of aquatic animals.Bacillus licheniformis FA6 is a probiotic isolated from the intestines of grass carp(Ctenopharyngodon idella),and has been shown improve growth performance,promote immune response and help the host digest through its enzyme activity.However,the fermentation process of B.licheniformis FA6 is unclear,which has limited its large-scale application in aquaculture.In this study,both traditional one-factor-at-a-time method and response surface methodology were used to optimize the fermentation medium and conditions based on the viable count of B.licheniformis FA6.We found that the optimal fermentation medium of B.licheniformis FA6 contained 70 g/L soluble starch,40 g/L casein peptone,2 g/L K2HPO4,1 g/L KH_(2)PO_(4),2 g/L Na_(2)HPO_(4),2 g/L MgSO_(4)and 8 g/L NaCl.The optimal fermentation conditions were an initial pH of 7.0,inoculation quantity of 1%,fermentation temperature of 28.8℃,fermentation time of 31h,liquid volume of 50 mL/250 mL and rotational speed of 160 r/min.Under these optimized conditions,the viable count of B.licheniformis FA6 reached 7.97×10^(9)CFU/mL,which was 8.1 times higher than before optimization.The acquisition of the optimal fermentation process of B.licheniformis FA6 provides a reference for the high-density production and industrial application of fish-derived Bacillus.