低温脂肪酶产生菌的筛选、鉴定及其部分酶学性质

Screening and Classification for Low-temperature Lipase-producing bacterium and Characterization of the Lipase

从南极乔治王岛冻土来源的 76株低温细菌中筛选到 13株低温脂肪酶产生菌 ,对其中的BTs10 0 2 2菌株进行鉴定。通过生理生化特征、16srDNA基因序列的同源性和系统发育分析发现 ,菌株BTs10 0 2 2属于假单胞菌属 (Pseudomonas) ,但与已定名的假单胞菌有一定的差异 ,与未定名的Pseudomonassp .PsB的亲缘关系最接近 ,故将其暂定名为Pseudomonassp .BTs10 0 2 2。对该菌脂肪酶的酶学性质初步研究表明 ,酶的最适作用温度为 2 4℃ ,对热敏感 ,6 0℃处理 30min仅残留 2 5 %酶活性 ,酶的适宜作用 pH范围在7.0～ 9.0 ,最适 pH为 8.0。

Thirteen Low temperature Lipase producing bacterial strains were screened from 76 isolates from tundra soils of King Geoge Island, Antarctica. The strain BTs10022, one of the producers, was identified. The traditional physiological and biochemical methods, together with the 16S rDNA sequence homology and phylogenetic analysis were applied in the bacterial classification. Results showed that the strain BTs10022 was differentiated from any of the named Pseudomonas species. Based on the phylogenetic analysis, the strain BTs10022 exhibited the highest levels of similarity to Pseudomonas sp. PsB isolated from the pinyon juniper woodland soils in a hot, dry, volcanic cinder field of the southwest U.S.. Therefor, we proposed that the strain BTs10022 was named as Pseudomonas sp. BTs10022. The optimal temperature of the action of this lipase was 24℃ and the enzyme was thermal lability, only 25% of its activity was remained after 30 min incubation at 60℃. The enzyme showed high lipolytic activity from pH 7.0 to 9.0 and its optimal pH for activity was 8.0.