渤海沉积物产脂肪酶细菌的筛选及其多样性分析

【目的】从渤海沉积物中分离筛选产脂肪酶细菌,分析其物种多样性,增加人们对渤海生态系统中产脂肪酶菌多样性的认识,获取高效产脂肪酶菌株,为海洋产脂肪酶微生物的挖掘提供菌群资源。【方法】分别将8个渤海沉积物样品梯度稀释涂布至吐温-80筛选平板和三丁酸甘油酯筛选平板,选择性分离产脂肪酶细菌;分析基于16SrRNA基因序列的系统发育关系,揭示这些细菌的分类地位和遗传多样性;利用对硝基苯酚法测定胞外脂肪酶活性,筛选出高效产脂肪酶菌株。【结果】从8个渤海沉积物样品中分离获得51株产脂肪酶细菌,这些菌株隶属于Bacteroidetes、Proteobacteria和Firmicutes三个门的8个属,其中Pseudoalteromonas(35.2%)、Marinobacter(23.5%)和Sulfitobacter(17.6%)是优势菌群;脂肪酶酶活性实验表明所有测定菌株都能够分泌脂肪酶,菌株70623分泌的脂肪酶酶活最高,为42.4 U/m L。【结论】渤海沉积物中可培养产脂肪酶细菌类群较为丰富,Pseudoalteromonas、Marinobacter和Sulfitobacter菌株是优势菌群,测定菌株所产胞外脂肪酶能力不同,获得了一株高效产脂肪酶菌株Marinobacter sp.70623。

Screening and diversity of lipase-producing bacteria in the sediments of Bohai Sea

[Objective] To uncover the diversity of cultivable lipase-producing bacterial isolated from the sediments of Bohai Sea and expand our knowledge on lipase-producing bacteria. Through screening efficient lipase production strains to expanding the marine lipase-producing microorganism resources. [Methods] The lipase-producing bacteria were isolated by using tween -80 plate and tributyrin plate from 8 sediment samples of the Bohai Sea. The diversity of these bacteria was evaluated through phylogenetic analyses based on 16S rRNA gene sequences. Using the p-nitrophenol method to detect extracellular lipase activity and select high lipase producing strains. [Results] A total of 51 lipase-producing strains were isolated from 8 sediment samples. The isolates were classified into 8 genera of three phyla including Bacteroidetes, Proteobacteria, and Firmicutes, with Pseudoalteromonas (35.2%), Marinobacter (23.5%) and Sulfitobacter (17.6%) as the dominant. Enzyme activity test showed that all the strains were able to secrete lipase, and a lipase-producing strain Marinobacter sp. 70623 possesses the highest lipase activity of 42.4 U/mL. [Conclusion] The cultivable lipase-producing bacteria isolated from the sediment of Bohai Sea are abundant with Pseudoalteromonas, Marinobacter and Sulfitobacter bacteria as the dominant groups, all the tested strains possess lipase activity, and the highest lipase activity producing strain Marinobacter sp. 70623 was obtained in this study.