仿刺参益生菌芽孢杆菌BC26培养基及发酵条件优化

摘要

以豆粕粉、玉米粉和糖蜜为营养要素，优化仿刺参益生菌芽孢杆菌BC26的培养基与发酵条件。采用单因素试验优化了芽孢杆菌BC26的培养基成分。试验结果表明，豆粕粉质量分数为7％时，菌体细胞密度最高；玉米粉质量分数（3％～6％）和糖蜜质量分数（3％～7％）对芽孢杆菌BC26菌株生长没有显著的影响。通过豆粕粉、玉米粉、糖蜜和起始pH值4因素3水平的正交试验，确定培养基的最佳组成为：7％豆粕粉、5％玉米粉、3％糖蜜、起始pH8。方差分析结果表明，豆粕粉和糖蜜对芽孢杆菌BC26菌株生长的影响均达到极显著水平（P＜0．01），玉米粉对芽孢杆菌BC26菌株生长的影响达到显著水平（P＜0．05）。在此基础上进一步优化了芽孢杆菌BC26的发酵条件。结果显示，该菌株的最佳摇瓶发酵条件为：培养温度25℃，转速150r/min，接种量2％，250mL三角瓶中培养基的装液量为25mL，经24h培养，菌数可达2．34×109个/mL，比优化前提高了51．95％。%The purpose of this study was to optimize medium and fermentation conditions of Bacillus sp . BC26 .The medium consisting of soybean meal ,corn flour and molasses was optimized using the single factor experiment .It was found that the maximal cell counts of Bacillus sp .BC26 was obtained when the soybean meal accounted for 7% .Corn flour (3% -6% ) and molass (3% -7% ) levels had no significant influence on growth of Bacillus sp .BC26 .The optimal medium for its cell counts was further determined by four factors and three levels of orthogonal test L9 (34 ) and was found as the following :soybean meal 7% ,corn flour 5% ,molasses 3% ,and pH8 .Analysis of variance showed that effects of soybean meal , molasses ,and corn flour on growth of Bacillus sp .BC26 were very significant level (P< 0 .01) ,and significant level (P< 0 .05) ,respectively .The optimum fermentation conditions were observed as the following :culture temperature of 25 ℃ ,shaking speed 150 r/min ,inoculum volume 2% ,25 mL medium in 250 mL Erlenmeyer flask and culture period 24 h .Bacillus sp .BC26 had biomass of 2 .34 × 109 cell/mL , 51 .95% higher when it was incubated in optimal fermentation conditions .