天山冻土产低温脂肪酶菌株的筛选及其多样性分析

Selective isolation and diversity of cold-adapted lipase-producing strains from permafrost soil at the terminus of a glacier in the Tianshan Mountains Selective isolation and diversity of cold-adapted lipase-producing strains from permafrost soil at the

摘要:

摘要：【目的】通过天山冻土细菌的分离和产低温脂肪酶菌株的筛选，了解天山冻土微生物的物种多样性和产脂肪酶菌株的系统发育多样性，为高效低温脂肪酶生物技术奠定基础。【方法】采用稀浓度的R2A、TSB平板涂布分离天山冻土中可培养细菌，通过选择性培养基筛选产低温脂肪酶的菌株。采用细菌常规生理生化实验、最适生长温度、耐盐性、产酶性能对分离菌株的生理学进行研究，通过16S rRNA基因序列分析确定产脂肪酶菌种的系统进化地位，通过BOX-PCR指纹技术对16S rRNA基因高度同源性的菌株进一步区分。【结果】分离筛选到78 株可培养低温菌，选择培养基显示有17株可产低温脂肪酶，其中8株在两种选择培养基中均可产脂肪酶和酯酶。17株产酶菌分别隶属于5个系统发育类群、6个属，其中假单胞菌属(Pseudomonas)占大多数(58.9%) 。【结论】天山冻土中产低温脂肪酶的细菌具有较丰富的系统发育多样性，依据生长温度，均属于耐冷菌。

Abstract:

Abstract:［Objective］The diversity of culturable lipase-producing bacterial strains from permafrost soils at the terminus of a glacier in the Tianshan Mountains was investigated. Isolation and molecular phylogenetic analysis were performed to expand our knowledge on diversity of psychrotrophic and psychrophilic bacteria. In addition, efforts were made focusing on screening for cold active lipases.［Methods］Lipase-producing bacterial strains were detected on tween 80 and olive oil plates, respectively. Identity and genetic diversity of strains isolated were determined by spatial 16S rRNA gene sequences and rep-PCR fingerprint. The physiological tests were carried out to determine the phonotypic differences between strains showing high similarity of 16S rRNA gene sequences.［Results］Of the total 17 bacterial stains exhibiting cold-adapted lipase activity, we found that only 8 stains were able to hydrolyze olive oil. Based on 16S rRNA gene sequences, the lipase-producing bacterial isolates fell in five phylogenetic groups: subclasses ?, ? and ? of Proteobacteria, Actinobacteria, and the Cytophaga-Flexibacter-Bacteroides (CFB) phylum. Nearly 59% of the isolates were affiliated with the genus Pseudomonas.［Conclusion］The results enrich our knowledge on the psychrotrophic bacterial diversity and biogeographic distribution of cold active lipases-producing bacteria in cold environments.