鲍肠道益生菌芽孢杆菌A3440菌株培养基及发酵条件优化

Optimization of Culture Medium and Fermentation Conditions of Probiotics Bacillus stratosphericus A3440 from Farmed Abalone

对一株来自于杂色鲍(Haliotis diversicolor)肠道并经证实具有显著促进其生长及免疫活性的同温层芽孢杆菌(Bacillus stratosphericus)A3440菌株进行培养基及发酵条件的优化研究,为该益生菌应用于鲍及其他水产动物的健康养殖奠定基础.以细菌芽孢率和蛋白酶活力为检测指标,采用单因素试验和正交设计试验优化发酵培养基组分及发酵条件.结果显示,该菌最佳发酵配方为:蛋白胨7g/L,酵母膏7g/L,NaCl 20g/L,CaCl20.20g/L;最佳发酵条件为:初始pH 9.0,培养温度30℃,种子液接种量8%,装液量30 mL(250 mL锥形瓶),培养时间24h.优化后芽孢率为94.3%,较基础培养基提高8.77%;蛋白酶活力为294.44U/mL,较基础培养基提高76.67%.

Bacillus stratosphericus A3440 isolated from farmed abalone Haliotis diversicolour has been verified as probiotic to improve the growth rate and the disease resistance of abalone.Based on high yield spore production and strong protease activity, the cul- ture medium and fermentation conditions of B. stratosphericus A3440 were optimized using a single factor test and orthogonal experiments.The results showed that the optimized medium components of A3440 were peptone 7 g/L, yeast extract 7 g/L, NaCl 20 g/ L, CaC12 0.20 g/L and the optimized culture conditions were initial pH 9.0, temperature 37 ℃ ,inoculation amount 8 % ,liquid volume 30 mL （in 250 mL flask）,and cultivation for 24 h.Under the optimized fermentation conditions, the spore yield was up to 94. 3 %, which increased by 8.77% compared with that from the initial medium,and the protease activity was 294.44 U/mL,which increased by 76.67%compared with that from the initial culture conditions.