低温好氧反硝化菌的分离鉴定及脱氮特性研究

Isolation and identification of a low temperature and aerobic denitrifier and its denitrification characteristics

从水库底泥样品中,以硝酸盐为唯一氮源驯化、分离并筛选出1株能在低温及好氧条件下进行高效反硝化的菌株DW4,经过生理生化和16S rDNA序列分析,并基于16S rDNA序列结果,构建了该菌株的系统发育树,最终确定菌株DW4为不动杆菌(Acinetobacter sp.)。考察了温度、初始pH、C/N及接种量对菌株DW4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pH值为6～9,温度为15～30℃,C/N不小于3,接种量为15%时,菌株DW4培养72 h后的硝氮去除率可达到90%以上。此外,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65%左右。实验结果表明,菌株DW4在寒冷地区低温季节微污染水体原位生物脱氮领域中具有很大的应用潜力。

A new strain named DW4 was obtained from reservoir sediment, 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 low temperature and oligotrophic conditions. The phylogenetic tree of the strain was produced, based on the experimental results of physiology and biochemistry and analysis of 16S rDNA sequence. The strain was identified as Acinetobacter sp. The effects of temperature, initial pH, C/N ratio and dosage on nitrate reduction activity as well as heterotrophic nitrification performance were investigated. The results indicated that the nitrate removal efficiency of DW4 strain could reach more than 90% after 72 h under the conditions of initial pH 6 to 9, temperature 15 to 30℃, C/N ratio no less than 3 and dosage 15%. Also, the strain DW4 had a good ability of simultaneous nitrification and denitrification, and the ammonia nitrogen removal efficiency could reach 65% during the incubation. The experimental results showed that strain of DW4 had great potential in the in-situ biodenitrification of micro-contaminated water in low temperature season of cold area