酿酒废水硫氧化细菌的分离鉴定及其硫氧化特性

Isolation and Identification of Sulfur-oxidizing Bacterium from Brewery Wastewater and Its Sulfur-oxidizing Characteristics

摘要:

本研究从酿酒废水中分离了一株化能自养硫氧化细菌LS2，通过16S rRNA基因和硫氧化功能酶基因soxB分析表明该菌株与Halothiobacillus亲缘关系最近，但Halothiobacillus sp. LS2的基因组中存在完整的固氮酶基因簇nif，其关键编码基因nifH与Acidithiobacillus属中A. ferrooxidans和A. ferrivorans相似性最高，均高于80%。通过细胞水平的比较研究，菌株LS2在有氮和无氮条件下均可生长，在1 mM NH4+的条件下生长量最高可达1.98×107 /mL，而无氮条件下生长量较有氮条件下少，最高可达1.37×107 /mL；基于基因表达分析，菌株LS2的nifH表达量因氮源存在而下调，硫代硫酸盐浓度增加而上调，其中在5 mM S2O32-浓度下其表达量上调了约33倍。说明该菌的固氮作用与硫氧化反应息息相关。本研究获得了一株具有固氮能力的化能自养硫氧化细菌，所获得的结果可为含硫化物废水的治理提供一种新思路。

Abstract:

In this study, a chemoautotrophic sulfur-oxidizing bacterial strain LS2 was isolated from brewery wastewater. The analyses of 16S rRNA gene and sulfur-oxidizing enzyme gene soxB revealed that this strain was most closely related to genus Halothiobacillus, although the genome of Halothiobacillus sp. LS2 had a complete gene cluster encoding nitrogen-fixing enzyme Nif; Its key gene nifH had the highest similarity to A. ferrooxidans and A. ferrivorans in the genus Acidithiobacillus (both of which were higher than 80%). A comparative study at the cellular level indicated that the strain LS2 was able to grow under both nitrogen and nitrogen-free conditions. The maximum growth of LS2 under the condition of 1 mM NH4+ could reach 1.98×107/mL, whilst the growth in the absence of nitrogen (up to 1.37×107/mL) was less than that in the presence of nitrogen. The gene expression analysis revealed that nifH expression of strain LS2 was down-regulated due to the presence of a nitrogen source but up-regulated with the increase of thiosulfate concentration. The expression of nifH was up-regulated by 33 times at a S2O32-concentration of 5 mM, indicating that nitrogen fixation was closely related to sulfur oxidation. In this study, a chemoautotrophic sulfur-oxidizing bacterium with nitrogen-fixing ability was obtained, and the obtained results can provide a new idea for the treatment of sulfide-containing wastewater.