一株地衣芽孢杆菌的性质研究及发酵培养基优化

目的]研究实验室自分离的地衣芽孢杆菌KL6作为微生物饲料添加剂的可行性,并对其发酵培养基进行优化,确定最佳培养条件,为工业化发酵提供依据。方法]运用表型试验对其进行生理生化评价及产酶评价;运用4因素3水平正交试验和单因素试验对其培养基进行改进,并对其发酵条件进行优化。结果]地衣芽孢杆菌KL6的D-葡萄糖产酸试验、硝酸盐还原试验、淀粉水解试验等均呈阳性;4种因素对活菌数影响的显著性次序为:MnSO4>NaCl>酵母粉>蛋白胨,对芽孢数影响的显著性次序为:MnSO4>蛋白胨>酵罐放大培养,最佳放罐时间应在14～16 h,获得的菌体数量约101.63×109个/ml,芽孢率为97.11%。结论]体外评价试验表明,地衣芽孢杆菌KL6具有作为微生物饲料添加剂的潜力;发酵培养基及条件优化试验表明,地衣芽孢杆菌KL6能够适于高密度液体发酵。该试验为以KL6为基础的微生物饲料添加剂的开发和大规模发酵培养提供了理论依据。

Research on the Character and Optimization of Fermentation Medium for Bacillus licheniformis, KL6

Objective] The aim was to study the feasibility of separating Bacillus licheniformis,KL6,as microbial feed additives,optimized its fermentation medium,and determined the optimum culture condition so as to provide a basis of industrial fermentation.Method] The physiological and biochemical and enzyme-producing of Bacillus licheniformis,KL6,were evaluated by phenotypic tests.Fermentation medium and conditions by and 4-factors and 3-levels orthogonal and single-factor expts improved the culture medium and optimized fermentation condition.Result] The number of viable cell was influenced by four factors in order of significance as follows:MnSO4> NaCl > Yeast extract > Peptone,the number of spores was MnSO4 > Peptone > NaCl >Yeast extract,and the optimum culture condition was: Peptone 1%,Yeast extract 0.5%,NaCl 1%,25% MnSO4.The suitable temperature of Bacillus licheniformis was 37 ℃.The fermentation process of the fermenter should be stop at 14-16 h,at that time the number of viable cell was 101.63×109 per milliliter,and the rate of spores was 97.11%.Conclusion] On the basis of the results of in vitro evaluation test,Bacillus licheniformis,KL6,had potential as microbial feed additives.On the basis of results that optimized fermentation medium and conditions,Bacillus licheniformis,KL6,was suitable for high-density fermentation of liquid.This experiment provided a theoretical basis to the development of microbial feed additives and large-scale fermentation which was based on KL6.