一株嗜盐嗜碱硫氧化菌的筛选、鉴定及硫氧化特性

Screening, identification and sulfide oxidation characteristics of a haloalkaliphilic sulfur oxidizing bacterium

【背景】沼气和天然气等清洁能源中往往会含有一定量的硫化氢,硫化氢的存在不仅污染环境,而且对人类危害很大。【目的】以硫代硫酸钠为唯一硫源从巴丹吉林沙漠盐碱湖岸边沉积物中分离筛选得到一株硫氧化菌BDL05,并研究其硫氧化特性。【方法】通过形态观察、生理生化特征及16S rRNA基因序列分析对硫氧化菌BDL05进行鉴定。【结果】菌株BDL05为革兰氏阴性菌,弧状,其16S rRNA基因序列与Thiomicrospira microaerophila ASL 8-2的相似性达99.8%,将其命名为Thiomicrospira microaerophila BDL05。该菌氧化硫代硫酸盐的最适pH为9.3,最适总钠盐浓度为0.8mol/L,在以硫化钠为硫源的气升式反应器中单质硫的生成率为94.7%,生成速率为3.0 mmol/(L·h)。【结论】菌株Thiomicrospira microaerophila BDL05为嗜盐嗜碱硫氧化菌,其耐盐耐碱性较强,比生长速率快,硫化钠氧化能力较强,是一株在气体生物脱硫方面具有应用价值的菌株。

[Background] Biogas and natural gas often contain a certain amount of hydrogen sulfide. Hydrogen sulfide is not only polluting the environment but is also harmful to humans. [Objective] In this study, a sulfur-oxidizing bacterium was screened from sodium alkali lake sediments in the Badain Jaran Desert using sodium thiosulfate as the sole energy source, and its sulfur oxidation properties were studied. [Methods] Strain BDL05 was identified by a variety of methods including Gram staining, colony morpholog, and 16 S rRNA gene sequence analysis. [Results] Strain BDL05 was a Gram-negative bacterium, helical, belonging to the family of Ectothiorhodospiraceae and Thiomicrospira genus. The 16 S rRNA gene sequence similarity of BDL05 to Thiomicrospira microaerophila ASL 8-2 reached 99.8%, so it was named as Thiomicrospira microscopila BDL05. The optimum pH for sodium thiosulfate was 9.3, and the optimum total sodium salt concentration was 0.8 mol/L. It had a strong ability to oxidize sodium sulfide. In the airlift reactor using sodium sulfide as the sulfur source, the yield of elemental sulfur was 94.7%, and the production rate was 3.0 mmol/(L·h). [Conclusion] This indicated that Thiomicrospira microaerophila BDL05 was a sulfur oxidizing bacteria which can be of a strong applicability in gas biological desulfurization.