海水异养硝化-好氧反硝化芽孢杆菌SLWX2的筛选及脱氮特性

从分离自刺参养殖环境的7株候选菌株中筛选出1株具有较强异养硝化和好氧反硝化能力的菌株SLWX_2,通过形态学特征、生理生化特性和16S rRNA基因测序分析鉴定其为花津滩芽孢杆菌(Bacillus hwajinpoensis).该菌株脱氮特性研究结果表明,SLWX_224 h对氨氮、亚硝酸氮和硝酸氮的去除率分别达到100%、99.5%和85.6%;当3种无机氮源同时存在时,菌株优先利用氨氮,再利用NO_2~--N和NO_3~--N,72 h 3种无机氮的质量浓度均降至0.013 mg·L~(-1)以下,表明该菌株能同时进行异养硝化和好氧反硝化完成脱氮;在氨氮负荷500 mg·L~(-1)、亚硝酸氮负荷100 mg·L·~(-1)和硝酸氮负荷200 mg·L~(-1)范围内,该菌的脱氮能力不受明显抑制,对3种形态的氮均有良好去除效果,96 h最多可去除180 mg NH_4~+-N、30 mg NO_2~--N和120 mg NO_3~--N,并且在硝化过程中没有亚硝酸氮积累.该菌株在海水养殖和高盐高氮工业废水的脱氮处理方面具有更大潜力.

Screening and Nitrogen Removing Characteristics of Heterotrophic Nitrification-Aerobic Denitrification Bacteria SLWX2 from Sea Water

In this study, an efficient heterotrophic nitrifying-aerobic denitrifying bacteria strain SLWX₂ was screened from 7 strains isolated from Stichopus japonicus culture ponds, with removal rates of NH₄⁺-N, NO₂^--N and NO₃^--N up to 100%, 99.5% and 85.6% within 24 h, respectively. Through morphologic observation, physiological characteristics and 16S rDNA sequence analysis, strain SLWX₂ was identified as Bacillus hwajinpoensis. The results of nitrogen removal characterization experiments indicated that, when NH₄⁺-N, NO₂^--N and NO₃^--N existed at the same time, SLWX₂ utilized NH₄⁺-N firstly, then utilized NO₂^--N and NO₃^--N, and removed almost all the inorganic nitrogen within 72 h, suggesting that it could achieve simultaneous nitrification and denitrification itself. The results of nitrogen tolerance examination indicated that strain SLWX₂ showed perfect nitrogen removal ability when the ammonia load was not above 500 mg·L^-1, nitrite load was not above 100 mg·L^-1 and nitrate load was not above 200 mg·L^-1, the maximal removal of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen withinn 96 h reached 180 mg, 30 mg and 120 mg, respectively. Moreover, there was no NO₂^--N accumulation during nitrification. This strain showed great potential in biological nitrogen removal of wastewater with high salt and nitrogen from mariculture and industries.