纤维素酶益生菌的选育及产酶条件

Reseach on induced breeding and production condition of cellulose-producing probiotics

从土壤中筛选出一株产纤维素酶的细菌B1,通过形态观察、生理生化特征及16S rDNA同源性序列分析,鉴定为蜡样芽孢杆菌(Bacillus cereus)。经微波-硫酸二乙酯复合诱变筛选出正突变株B1-1,其纤维素酶酶活达到0.373 U/mL,经5次传代后,该菌株遗传性状稳定,且胃肠道耐受性良好;B1-1菌株最佳产酶条件为20 g/L麦芽糖,2.5 g/L硫酸铵,pH值为5.0,37℃下培养36 h。

Strain B1 with cellulase activity was screened from soil, which was identified as Bacillus cereus according to the characteristics of morphology, physiology and biochemistry tests and the comparison of 16S rDNA sequence. Strain B1-1 with high cellulase activity was filtrated by microwave and DES mutagenesis, and its cellulase activity reached 0. 373 U/mL. Strain B1-1 was genetically stable after five subcultures and well survived in the gastrointestinal tract. The optimum conditions for cellulase production were 20 g/L maltose, 2. 5 g/L ammonium sulphate, pH 5.0 and culturing for 36 h at 37 ℃.