异养硝化-好氧反硝化菌ZH7的分离鉴定及脱氮特性研究

Isolation,identification and nitrogen removal characteristics of heterotrophic nitrification-aerobic denitrification bacterium ZH7

从养殖塘底泥中分离筛选出一株具有异养硝化-好氧反硝化功能的菌株ZH7,通过形态观察、生理生化测定和16S rDNA序列将菌株鉴定为不动杆菌属(Acinetbacter sp.)。研究不同环境因素(碳源、碳氮比、温度、pH、摇床转速、NaCl浓度)对菌株生长及脱氮性能的影响,并在最佳条件下,探究菌株在单一氮源和混合氮源中的异养硝化-好氧反硝化性能。结果表明:ZH7可以乙酸钠为碳源,在C/N为12~16、温度30℃、摇床转速180 r/min、pH 7~9的条件下对氨氮(NH_(4)^(+)-N)和硝酸盐氮(NO_(3)^(-)-N)的去除率均可达到95%以上。混合氮源条件下(氨氮和硝酸盐氮),菌株会优先利用氨氮。氮源去除过程符合Compertz模型,菌株对氨氮的最大去除速率明显高于硝酸盐氮和亚硝酸盐氮,R_(m)分别为12.61、7.17和7.23 mg/(L·h)。菌株ZH7具有高效的脱氮能力,可作为生物脱氮候选菌株。

A heterotrophic nitrification-aerobic denitrification strain ZH7 was isolated from aquaculture pond sediment.The strain ZH7 was identified as Acinetobacter sp.by morphological observations,physiological and biochemical assays and 16S rDNA sequencing.The impact of various factors(carbon source,C/N ratio,temperature,pH,shaking speed,NaCl concentration)on the strain’s growth and denitrification performance was investigated.And the heterotrophic nitrification and aerobic denitrification performance of the strain in single nitrogen source and mixed nitrogen source under the optimal conditions was also investigated.The results showed that the strain ZH7 could use sodium acetate as a carbon source,and achieved removal rates of ammonium nitrogen(NH+4-N)and nitrate nitrogen(NO-3-N)exceeding 95%under conditions of C/N of 12-16,temperature of 30℃,shaking speed of 180 r/min and pH value of 7-9.In mixed nitrogen source conditions(ammonium and nitrate nitrogen),the strain preferentially utilized ammonium nitrogen.The nitrogen removal process followed the Compertz model,with the maximum removal rate for ammonia nitrogen significantly higher than that for nitrate nitrogen and nitrite nitrogen,with R m of 12.61,7.17 and 7.23 mg/(L·h),respectively.The strain ZH7 demonstrated the efficient denitrification capabilities and can be considered a potential candidate for biological denitrification.