艾丁湖可培养嗜盐菌多样性及功能酶、抗菌活性筛选

Diversity and functional enzymes, antimicrobial activity screening of culturable halophilic bacteria from Aiding Lake

【目的】探究艾丁湖可培养嗜盐菌的多样性、功能酶活性以及抗菌活性,进一步了解其次级代谢产物情况,为新型生物活性物质的发掘提供依据。【方法】选用以20种糖及糖的衍生物作为唯一碳源的寡营养培养基从艾丁湖5个样点中分离得到298株嗜盐菌,根据形态特征去重复后,选取62株菌运用16S r RNA基因系统发育分析的方法研究样品中嗜盐菌的多样性;从不同类群选取22株代表菌株,采用点接法进行3种功能酶的筛选,运用平板对峙法检测代表菌株对12种病原菌的抗菌活性。【结果】从5%、10%和15%3个盐浓度中分别分得221、54和23株嗜盐菌,获得的嗜盐菌分布在9个科18个属;其中放线菌分布于4个属,细菌分布于14个属;Nocardiopsis和Pontibacillus属为艾丁湖可培养嗜盐菌的优势类群,分别占17.7%和16.1%;有15株嗜盐菌相似性低于98.5%,可能为潜在新种。所选取的22株代表菌株中,分别有68.2%、22.7%和72.7%的实验菌株具有蛋白酶、淀粉酶和酯酶活性;45.5%的代表菌株对12种病原菌表现出了抗至少1种病原菌的活性,其中一株Nocardiopsis属放线菌能抗9种病原菌,表现出了广谱的抗菌活性。【结论】新疆艾丁湖土样中嗜盐菌的多样性较丰富,而且具有较好的生物活性,为后续进一步研究其次级代谢产物提供了依据。

[Objective] To explore secondary metabolites and new bioactive substances, the diversity, functional enzyme activity and antimicrobial activity of halophilic bacteria from Aiding Lake were studied. [Methods] A total of 20 sugars and sugar derivatives were selected as the sole carbon source of medium, and 298 halophilic bacteria were isolated from 5 samples of Aiding Lake. Based on the morphological characteristics, 62 representative strains were selected for 16 S r RNA gene sequencing and phylogenetic analysis. Twenty-two halophilic bacteria were chosen from different species to screen functional enzyme activity and antimicrobial activity. Activity for 3 functional enzyme were tested by noculating single colony method. Antimicrobial activity for 12 pathogenic bacteria and fungus were tested by plate confront method. [Results] There were 221, 54, 23 halophilic bacteria isolated from 5%, 10%, 15% salt concentration respectively. They were distributed in 9 families, 18 genera. Actinobacteria were distributed in 4 genera, and bacteria were distributed in 14 genera. Nocardiopsis and Pontibacillus were dominant groups of culturable halophilic bacteria from Aiding Lake, comprising 17.7% and 16.1% respectively. The 16 S r RNA gene sequence similarity of 15 halophilic bacteria were lower than 98.5%, which may present potential novel species. Among the 22 representative strains, 68.2%, 22.7%, 72.7% of them showed positive result for protease activity, amylase activity and asterase activity respectively. And 45.5% of the tested strains showed at least one kind of microbial activity against 12 pathogenic bacteria and fungus. Especially, one Nocardiopsis strain exhibited extensive antagonism against 9 pathogenic bacteria and fungus. [Conclusion] The halophilic bacteria of Aiding Lake in Xinjiang has abundant diversity and good biological activity, which provides the basis for further study on secondary metabolites.