1株贫营养好氧反硝化菌的分离鉴定及其脱氮特性

从水库底泥样品中,以硝酸盐为唯一氮源进行驯化、分离筛选出1株能在贫营养及好氧条件下进行高效反硝化的菌株PY8,经过电镜形态学观察、生理生化和16S rDNA序列分析,并基于16SrDNA序列结果,构建了该菌株的系统发育树,最终确定菌株PY8为根瘤菌Rhizobiumsp.。考察了初始pH值、温度、C/N、初始硝酸钠质量浓度、投菌量对菌株PY8硝酸盐还原活性的影响,以及该菌株的异养硝化性能。结果表明,在pH6.0～10.0,温度25～30℃,C/N1.0～9.0,初始硝酸钠质量浓度0.01～0.50g·L-1,投菌量1%～15%时,菌株PY8培养72h后的硝氮去除率可达到95%以上。另外,该菌株具有同时硝化-反硝化作用,在培养过程中氨氮去除率可达到58%左右。实验结果表明,菌株PY8在微污染水体生物脱氮领域中具有很大的应用潜力。

Isolation and identification of an oligotrophic and aerobic denitrification and its denitrification characteristics

The purpose was to characterize a newly isolated strain obtained from reservoir sediments and designated PY8,with respect to degrade nitrate.The strain was isolated by special domestication in liquid medium with nitrate as sole nitrogen source,which also had a desirable denitrification performance under aerobic and oligotrophic conditions.The phylogenetic tree of the strain was produced on the basis of morphology observation by SEM,experimental results of physiology and biochemistry and analysis of 16S rDNA sequence.The strain was identified as Rhizobium sp.The effects of initial pH,temperature,C/N ratio,initial sodium nitrate concentration and dosage on nitrate reduction activity as well as heterotrophic nitrification performance were investigated.The results indicated that the nitrate removal efficiency of PY8 strain could reach more than 95% after 72 h,under conditions of initial pH 6.0～10.0,temperature 25～30 ℃,C/N ratio 1.0～9.0,initial sodium nitrate concentration 0.01～0.50 g·L-1 and dosage 1%～15%.Also,the strain PY8 had a good ability of simultaneous nitrification and denitrification,and the ammonia removal efficiency could reach 58% during the culture.The study showed that strain PY8 had great potential in the biodenitrification of micro-polluted water.