好氧反硝化细菌SY-D-22的分离、优化及脱氮机理

Aerobic denitrifying bacterium SY-D-22: isolation, optimization of denitrification conditions, and characterization of denitrification mechanism

摘要:

【背景】在处理含硝酸盐氮的废水中，常见微生物不能同时高效去除硝酸盐氮和总氮，导致处理废水时往往使用多种微生物复合菌剂或者使用复杂的工艺。【目的】高效、安全地去除水中的硝酸盐氮和总氮。【方法】富集筛选出一株新型高效好氧反硝化细菌，对其进行16S rRNA基因鉴定。利用响应面法对其影响脱氮因素进行优化并探索其最佳脱氮条件。研究其对含硝酸盐氮废水的反硝化能力及脱氮特性。【结果】从活性污泥中筛选获得一株新型高效好氧反硝化细菌SY-D-22，经鉴定为葡萄球菌属(Staphylococcus)。响应面法优化其最佳反硝化条件为：pH 8.18，C/N为13.39，温度31.43 °C，摇床转速130 r/min。当以最佳碳源柠檬酸钠为唯一碳源时，对于100 mg/L浓度的NO₃^--N去除率可达100%，同时对于总氮(total nitrogen, TN)的去除率为95.34%，具有高效脱氮能力。【结论】从活性污泥中筛选出一株新型好氧反硝化细菌Staphylococcus SY-D-22，通过响应面法条件优化，菌株的硝酸盐氮去除率达到100.00%，总氮去除率达到95.34%，具有去除硝酸盐氮和亚硝酸盐氮能力。

关键词:反硝化脱氮;响应面法;好氧反硝化;同步硝化反硝化;总氮;条件优化

Abstract:

[Background] In the treatment of wastewater containing nitrate, common microorganisms cannot efficiently remove nitrate while having a high removal rate for total nitrogen, which results in the use of multiple bacteria or complex processes.[Objective] To efficiently and safely remove nitrate nitrogen and total nitrogen from water. [Methods] An efficient aerobic denitrifying bacterium was isolated from activated sludge and sequenced for the 16S rRNA gene. The response surface methodology was employed to optimize the factors affecting nitrogen removal. Further, the denitrification capacity and characteristics of the strain for nitrate-containing wastewater were studied. [Results] An efficient aerobic denitrifying bacterium SY-D-22 was isolated from activated sludge and identified as Staphylococcus. The best denitrification efficiency of the strain was achieved under pH 8.18, C/N ratio of 13.39, 31.43℃, and 130 r/min. With sodium citrate as the sole carbon source, strain SY-D-22 rapidly removed nitrogen under aerobic conditions, demonstrating the nitrate nitrogen (100 mg/L) removal rate up to 100% and the total nitrogen removal rate of 95.34%. [Conclusion] Staphylococcus SY-D-22 was isolated from the activated sludge. After the denitrification conditions were optimized by response surface methodology, the removal rates of the strain for nitrate nitrogen and total nitrogen was up to 100.00% and 95.34%, respectively. This strain is capable of removing nitrate nitrogen and nitrite nitrogen.

Key words:denitrification;response surface methodology;aerobic denitrification;simultaneous nitrification and denitrification;total nitrogen;condition optimization