耐盐异养硝化-好氧反硝化菌Bacillus megatherium N07的分离及脱氮特性

Isolation of Halophilic Heterotrophic Nitrification-aerobic Denitrification Bacterium Bacillus megatherium N07 and Its Denitrification Characteristics

基于异养硝化-好氧反硝化菌的生物脱氮技术可有效去除污水中的氮素。高盐废水处理过程中存在抑制微生物生长、脱氮效率低等诸多短板。为解决高盐废水难脱氮问题,从农药厂化工污水中筛选出一株耐受8%(W/V)高盐浓度的异养硝化-好氧反硝化菌株,命名为N07。在不同盐度和不同溶氧条件下测定了菌株的氮素去除率,并探究了单因素环境因子对菌株脱氮性能的影响。结果表明:菌株N07鉴定为巨大芽孢杆菌(Bacillus megatherium);能耐受8%盐度且繁殖旺盛,对氨氮和亚硝态氮去除率最高达到73.61%和83.56%,属于中度嗜盐菌;该菌在有氧条件下表现出高效的反硝化能力,12 h对硝态氮和亚硝态氮去除率为11.87 mg/(L· h)和8.26 mg/(L· h);菌株在碳源为蔗糖、C/N为25、pH为7、转速160 r/min、温度为28℃时,硝化能力最佳。Bacillus megatheriumN07因能在高盐分环境降解氮素的特性,为异养硝化-好氧反硝化菌在沿海养殖业等高盐含氮污水处理的实际应用提供参考。

Biological nitrogen-removing technology based on heterotrophic nitrification and aerobic denitrification bacteria may effectively remove nitrogen in sewage.There are many shortcomings in the treatment of high salt wastewater,such as inhibiting microbial growth and low nitrogen removal efficiency.In order to solve the problem of difficult nitrogen removal from high salt wastewater,a strain of heterotrophic nitrification and aerobic denitrification with high salt concentration of 8%(W/V)was selected from chemical wastewater of agricultural pharmaceutical factory and named N07.The denitrification rate of the strain was measured under different salinity and dissolved oxygen conditions,and the effects of single environmental factors on the denitrification performance of the strain was investigated.The results showed that strain N07 was identified as Bacillus megatherium.It tolerated 8% salinity and reproduced vigorously.The removal rates of ammonia nitrogen and nitrite nitrogen were up to 73.61% and 83.56%,belonging to moderate halophilic bacteria.The bacterium showed high denitrification ability under aerobic conditions,with nitrate and nitrite removal rates of 11.87 mg/(L· h)and 8.26 mg/(L· h)at 12 h.The best nitrification capacity was obtained when carbon source was sucrose,C/N was 25,pH was 7,rotation speed was 160 r/min and temperature was 28℃.B.megatherium N07 can degrade nitrogen in high salinity environment,which provides reference for the practical application of heterotrophic nitrification and aerobic denitrification bacteria in the treatment of high salinity nitrogen wastewater such as coastal aquaculture industry.