一株硝化脱氮除臭菌的筛选鉴定及其多途径氮代谢功能的研究

从江门某污水处理厂活性污泥中分离出一株能够高效脱除氨气的菌株JN-4.通过菌株形态观察、生理生化及16SrDNA分子鉴定,发现菌株JN-4与枯草芽孢杆菌(Bacillus subtilis)亲缘关系最为接近,同源性达到99%,认为JN-4为一株枯草芽孢杆菌(Bacillus subtilis).好氧培养条件下,以葡萄糖为碳源,JN-4在32h内对NH4+-N和NO2--N的总削减率能够达98.51%和84.50%,体系中总氮的削减率达到63.1%和16.9%,N2的产生量分别为3.72mmol·L-1和0.62mmol·L-1.好氧培养条件下,以KNO3为唯一氮源,NO3--N初始浓度为82.47mg·L-1,32h内体系中NO3--N的总削减率达到96.54%,体系中总氮的削减率达49.6%,产生1.44mmol·L-1的N2,反应中检测到有NH4+-N迅速积累,但会随着时间进行同步转化,可见JN-4不仅能够高效硝化脱氨,同时具有高效好氧反硝化的能力.JN-4在厌氧以及乙酸钠作为碳源的条件下,利用NH4+-N效率大大降低,但是能够在NO3--N存在时进行NO3--N还原(反硝化).JN-4能够进行多途径氮代谢,为一株异养硝化-好氧反硝化偶联的菌株,具有重要的应用价值.

Isolation and identification of a denitrifying and deodorizing Bacillus subtilis strain with multiple nitrogen metabolism pathways

To study aerobic denitrifying and deodorization, strain JN-4 was isolated from the activated sludge of a wastewater treatment plant in Jiangmen. The strain was identified as Bacillus subtilis.based on its morphological characteristics, physiological and biochemical properties and phylogenetic analysis of its 16S rDNA sequence. Using JN-4 in a reactor under aerobic conditions, NH+4-N and NO-2-N losses reached 98.51% and 84.50% and total nitrogen loss could reach 63.1% and 16.9% respectively. JN-4 could reduce NO-3-N into NH+4-N with organic carbon source and potassium nitrate as nitrogen source. Under these conditions, NO-3-N and total nitrogen losses could reach 96.54% and 49.6% respectively. The NH+4-N accumulation could be transformed together with NO-3-N. JN-4 could highly oxidize NH+4-N and grow with a glucose carbon source and it also had aerobic denitrification ability. Under anaerobic conditions, strain JN-4 could still reduce NO-3-N with sodium acetate as the sole carbon source. In the cells of strain JN-4 with multiple paths of nitrogen metabolism, coupling of heterotrophic nitrification and aerobic denitrification is feasible and is of practical value in water treatment.