脂肪酶产生菌Bacillus subtilis FS321的分离鉴定及其产酶条件的初步优化

Isolation and Identification of a Lipase-producing Strain of Bacillus subtilis FS321 and Its Preliminary Optimization for Lipase Production

从北方堆肥试样中分离筛选得到1株中度耐热脂肪酶产生菌,编号为FS321。对该菌株进行产酶条件的初步优化,得到了摇瓶发酵条件:产酶培养基M4,发酵周期为48～60 h,摇瓶发酵温度为37℃,通气量为25 mL/250 mL锥形瓶。所产脂肪酶在50℃,pH 9.0时表现最高活性。为了鉴定该菌株,分析该菌的细胞脂肪酸谱,克隆测序了其16S rDNA基因序列,系统进化树及细胞脂肪酸组分分析均表明,FS321与Bacillus subtilis具有最紧密的亲缘关系。

A moderate thermostable lipase producing strain FS321 was isolated from the dunghill soil in the northern of China. The fermentation conditions of lipase-producing were preliminary optimized. The optimum culture medium was of M4, fermentation cycle of 48-60 h, culture temperature of 37℃, and oxygen --consumption of 25mL medium for each 250mL flask. The lipase showed the highest activity at the temperature of 50℃ and pH9.0. To further identify the strain, the cellular fatty acids composition of FS321 was analyzed, and the 16S rDNA gene was cloned and sequenced. Both the cellular fatty acids compositions and the phylogenetic tree based on the 16S rDNA sequence of FS321 showed that the bacterium FS321 was highly homology to that of Bacillus subtilis.