一株海水异养硝化-好氧反硝化菌系统发育及脱氮特性

【目的】确定一株分离自海水的异养硝化-好氧反硝化菌的系统发育地位并探索其脱氮特性和机理,以期为解释异养硝化-好氧反硝化机理以及改进海水养殖及废水的生物脱氮工艺提供理论依据。【方法】通过形态观察、生理生化实验和16S rRNA基因序列分析,鉴定该菌株;通过测定菌株在不同无机氮源降解测试液中的生长和脱氮效率,分析其异养硝化和好氧反硝化性能。【结果】经鉴定该菌株属于盐单胞菌属(Halomonas);最适生长条件为盐度3%、pH 8.5、温度28℃、碳氮比10:1,在盐度为15%的培养液中仍能生长;可以同时去除氨氮、亚硝酸氮和硝酸氮,24 h时对NH4+-N、NO2--N、和NO3--N的去除率可分别达到98.29%、99.07%、96.48%,3种形态无机氮同时存在时,会优先利用NH4+-N,且总无机氮去除率较单一存在时更高,说明该菌株可实现同步硝化反硝化。【结论】该分离自海水的异养硝化-好氧反硝化菌属于盐单胞菌属(Halomonas),在高盐环境中仍能生长,同时具有高效的异养硝化和好氧反硝化能力,能够独立完成脱氮的全部过程。

Phylogenetic analysis and nitrogen removal characteristics of a heterotrophic nitrifying-aerobic denitrifying bacteria strain from marine environment

Objective] We determined the phylogenetic position of a heterotrophic nitrifying-aerobic denitrifying bacterium X3,and detected its nitrogen removal characteristics for providing evidence to explain the principle of heterotrophic nitrification-aerobic denitrification and to improve the process in purification of marine-culture wastewater.Methods] The evolutionary position of the strain was determined based on its morphological,physiological,biochemical characteristics and 16SrRNA gene sequence.The nitrification-denitrification ability of this strain was detected by detecting its nitrogen removal efficiency and growth on different inorganic nitrogen source.Results] Strain X3 was identified as Halomonas sp.It grew optimally at salinity 3%,pH 8.5,C:N 10:1 at 28℃,and it could still survive at 15% salinity.The removal of NH+4-N,NO-2-N and NO-3-N was 98.29%,99.07%,96.48% respectively within 24 h.When three inorganic nitrogen existed simultaneously,it always utilized ammonia firstly,and the total inorganic nitrogen removal was higher than with only one nitrogen,suggesting that strain X3 has the ability of simultaneous nitrification and denitrification and completing the whole nitrogen removing process.Conclusion] Strain X3 belonged to the genus of Halomonas.It had strong simultaneous nitrification and denitrification capability and could live in high-salinity environment.