一株耐高氨氮好氧反硝化细菌的鉴定及脱氮性能研究

Identification and denitrification performance of a high ammonia nitrogen-resistant aerobic denitrifying bacteria

  • 摘要: 氨氮 (NH4 +-N)、硝态氮 (NO3 -N)、亚硝态氮 (NO2 -N) 等含氮 (N) 化合物是工厂化养殖系统中的主要污染物,水中N浓度较高易造成养殖水体污染并危害水生动物的安全,而好氧反硝化细菌被广泛用于养殖尾水的N降解。为获得一株能安全高效处理高NH4 +-N废水的菌株,对从养殖池塘筛得的耐高NH4 +-N好氧反硝化细菌WM28进行了研究。运用形态学观察、生理生化及16S rRNA基因测序对该菌株进行种属鉴定;采用抗生素实验、斑马鱼(Danio rerio) 攻毒实验对菌株进行了环境及生物安全性评估;在3种单一氮源模拟废水下测定其生长与脱氮性能,并在高浓度NH4 +-N模拟废水中对其进行脱氮能力测试。经鉴定,WM28为红球菌属赤红球菌 (Rhodococcus ruber);有较高的抗生素敏感性及较好的生物安全性。在单一NH4 +-N、NO3 -N、NO2 -N模拟废水中,培养48 h后N去除率分别为100%、76.3%、66.99%;高浓度NH4 +-N模拟废水结果显示:100~500 mg·L−1高浓度NH4 +-N模拟废水在48 h后的NH4 +-N去除率为100%;700 mg·L−1 NH4 +-N在116 h后的去除率在88%以上;在第120小时,NH4 +-N初始质量浓度为1 000 mg·L−1时仍有脱氮能力,去除率为74.38%,说明菌株WM28具有较好的高NH4 +-N耐受性。综上所述,菌株WM28是一株耐NH4 +-N、安全且高效的好氧反硝化菌,在处理养殖尾水、工业废水上有较好的应用前景。

     

    Abstract: Ammonia (NH4 +-N), nitrate (NO3 -N) and nitrite (NO2 -N) are the main contaminants in industrial aquaculture systems. High nitrogen concentration in water is likely to cause aquaculture water pollution and endanger the safety of aquatic animals. Aerobic denitrifying bacteria are widely used to remove nitrogen-containing aquaculture wastewater. In order to obtain a strain that can safely and efficiently treat wastewater with high ammonia nitrogen concentration, we studied the aerobic denitrifying bacteria WM28 with high ammonia nitrogen resistance screened from aquaculture ponds. The strain was identified through morphological observation, physiological and biochemical tests and 16S rRNA gene sequencing. The environmental and biological safety of the strains were evaluated through antibiotic tests and zebrafish (Danio rerio) toxicity tests. The growth and denitrification performance were measured in three single nitrogen source simulated wastewater, and the denitrification capacity was tested in high concentration ammonia nitrogen simulated wastewater. WM28 was identified as Rhodococcus ruber with high antibiotic sensitivity and good biosafety. The removal rates were 100%, 76.3% and 66.99% after 48 h incubation in single NH4 +-N, NO3 -N and NO2 -N media, respectively. Their removal rates of NH4 +-N reached 100% at high concentrations of 100–500 mg·L−1 NH4 +-N in simulated wastewater experiment after 48 h. 700 mg·L−1 NH4 +-N was removed by more than 88% after 116 h. At 120th hour, the initial NH4 +-N concentration of 1 000 mg·L−1 was still capable of denitrification with a removal rate of 74.38%, which indicates that strain WM28 has great tolerance to high ammonia nitrogen. In summary, strain WM28 is a safe and efficient aerobic denitrifying bacteria with high ammonia tolerance, and has promising application prospects in the treatment of aquaculture and industrial wastewater.

     

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