新疆泥火山产酶嗜盐放线菌的筛选及多样性

Diversity of halophilic actinomycetes from mud volcano in Xinjiang

【目的】了解新疆乌苏泥火山嗜盐放线菌及其产酶功能多样性。【方法】分别采用含有5%与10%NaCl的5种分离培养基,稀释平板涂布法对泥火山土壤样品进行分离;利用五种筛选培养基定性检测酶活性;在形态特征、耐盐性实验及16SrDNA基因测序的基础上进行系统发育学分析。【结果】获得嗜盐放线菌43株,极端嗜盐放线菌3株。4株嗜盐放线菌产脂肪酶,30株产半乳糖苷酶,27株产淀粉酶,6株产酯酶,4株产纤维素酶,1株同时产4种酶。系统发育学分析结果表明其中24株为拟诺卡氏菌属(Nocardiopsis),1株为链霉菌属(Streptomyces)。产两种酶的菌株10006与Nocardiopsis exhalans(AY03600)相似性为96.64%(小于97%),可能是潜在的新种。【结论】本研究表明新疆乌苏泥火山中存在大量的产半乳糖苷酶及淀粉酶的嗜盐放线菌,所分离到的拟诺卡氏菌属产酶多样性比较高,并且潜藏着新的微生物资源。

[Objective] To know halophilic actinomycetes and their enzyme-producing ability from mud volcano in Usu County, Xinjiang, China. [Methods] Soil samples in mud volcano were isolated with five isolation media containing 5% and 10% NaCl （w/v） with dilution-plate method. The activities of lipase, galactosidase, amylase, esterase and cellulase from isolated strains were qualitatively detected by using five selective media. Base on morphological characteristics, test of salt tolerance, screening of enzymatic characters and sequencing of 16S rDNA gene, strains were selected for phylogenetic analysis. [Results] A total of 43 halophilic actinomycetes and 3 extreme halophilic actinomycetes were obtained. Screening results for enzyme activity showed that 4 halophilic actinomycetes produced lipase, 30 strains produced galactosidase, 27 strains produced amylase, 6 strains produced esterase, 4 strains produced cellulose and 1 strain produced 4 enzymes simultaneously. According to 16S rDNA sequence analysis, 24 of 25 detected sequences were affiliated with Nocardiopsis, and the other one was Streptomyces. In the phylogenetic tree, strain 10006 producing 2 enzymes and Nocardiopsis exhalans （AY03600）showed 96.64% similarity （less than 97%）, which indicated that strain 10006 was a possible new species. [Conclusion] There are plenty of galactosidase or amylase-producing halophilic actinomycetes and higher enzyme-producing diversity of Nocardiopsis in Usu mud volcano. In addition, there are potential microbial resources in this extreme environment.