一株耐盐反硝化细菌的筛选、鉴定和特性及其产物四氢嘧啶的检测

A salt-tolerant denitrifying bacterial strain: screening, identification, characterization, and detection of its product ectoine

摘要:

【背景】石化工业废水具有高盐含氮的特点，高盐度会对微生物代谢造成抑制，导致普通反硝化微生物难以在高盐环境下有效脱氮。【目的】筛选在高盐条件下仍能保持反硝化能力的菌株并研究其特性。【方法】富集筛选出一株耐盐反硝化细菌，对其进行生理生化特性和16S rRNA基因序列鉴定，对其生长条件进行优化并测定该菌株反硝化能力，对菌株在高盐环境下的产物进行定性定量分析。【结果】经鉴定菌株YA16-1为表皮短杆菌(Brevibacterium epidermidis)，可对硝态氮进行反硝化作用，在盐度为3%、初始氮浓度为55 mg/L的条件下，18 h的硝态氮转化率达到97%；初始硝态氮浓度为250 mg/L时，24 h内硝态氮转化率达到100%。该菌株的最适生长条件为：2% NaCl，碳源为玉米芯粉，氮源为酵母粉，pH值为6.0，培养温度为30 ℃。菌株在盐度为2%-15%的培养基内生长良好。在15%盐度下，菌株通过产四氢嘧啶维持渗透压，产量为0.89 mg/mL。【结论】菌株YA16-1具有良好的耐盐能力和反硝化能力，在高盐废水处理、保护生态环境和四氢嘧啶的制备具有潜在的应用价值。

关键词:反硝化细菌;耐盐菌;高盐含氮废水;四氢嘧啶

Abstract:

[Background] Petrochemical wastewater contains nitrogen and has high salt content, which inhibits microbial metabolism and makes it difficult for common denitrifying microorganisms to effectively remove nitrogen. [Objective] To screen out and characterize the strains capable of efficiently removing nitrogen under high salt conditions. [Methods] A strain of salt-tolerant denitrifying bacterium was screened out and identified based on the physiological and biochemical properties and 16S rRNA gene sequence. The growth conditions of the strain were optimized and the denitrification capacity was measured. The products of the strain under high salt conditions were analyzed qualitatively and quantitatively. [Results] The strain YA16-1 was identified as Brevibacterium epidermidis and had the ability of denitrifying nitrate-nitrogen. It showed the nitrate-nitrogen removal rates of 97% in 18 h at 3% salinity and 55 mg/L initial nitrogen and 100% in 24 h at 250 mg/L initial nitrate-nitrogen. The optimum growth conditions for this strain were 2% NaCl, corn cob meal as the carbon source, yeast powder as the nitrogen source, pH 6.0, and 30 ℃. The strain grew well in media with salinity ranging from 2% to 15%. At 15% salinity, the strain maintained osmotic equilibrium by producing ectoine with the maximum titer of 0.89 mg/mL. [Conclusion] YA16-1 has good salt tolerance and denitrifying ability, demonstrating the potential of being applied in the treatment of high-salt wastewater and the production of ectoine.

Key words:denitrifying bacterium;salt-tolerant bacterium;high-salt nitrogen-containing wastewater;ectoine