氨氮对异养硝化菌Acinetobactor sp.活性影响及动力学特性分析

异养硝化菌株Acinetobactor sp.JQ1004能够在初始氨氮浓度为0~2000mg/L范围内进行生长和氮源代谢，菌株在初始氨氮浓度为2500mg/L条件下被完全抑制，无法生长.当菌株在温度为30℃，pH7.5，转速为160r/min，初始氨氮浓度分别为100，300，500，700，1000，1500，2000，2500mg/L条件下培养时，菌株的最大比生长速率分别为0.251，0.308，0.286，0.243，0.197，0.115，0.088h^-1，相应的最大比氨氮降解速率分别为1.335，1.906，1.859，1.759，1.562，1.286，0.965g/（gDCW·d）.在高浓度氨氮和游离氨的抑制作用下，菌株的比生长速率及对氨氮的比降解速率随初始氨氮浓度的增加呈先增加后降低的趋势.3种基质抑制动力学模型（Haldane，Yano，Aiba模型）均能够很好地模拟菌株随初始氨氮浓度的生长变化规律，对应地相关系数分别为0.9944，0.9983和0.9929.由Haldane模型可知，菌株在不同初始氨氮浓度（游离氨）条件下的最大氨氮比降解速率μ_max为2.604h^-1，基质亲和系数K_s为22.57mg/L，基质抑制系数K_i为1445.31mg/L.其中由K_i值远大于自养菌（硝化细菌及厌氧氨氧化菌等）的值，这表明异养硝化菌株Acinetobactor sp.JQ1004比自养菌具有更强的抗抑制能力.另外，菌株在游离氨浓度为5.436mg/L时，比生长速率达到最大值0.583h^-1.以上研究结果表明，菌株JQ1004在处理高氨氮废水中具有潜在的应用前景.

Inhibition of initial ammonia and free ammonia nitrogen on Acinetobactor sp. and their biokinetics

The strain JQ1004 with capability of heterotrophic nitrification were able to grow and metabolism under different initial ammonium concentrations in range of 0~2000mg/L.However,the strain were completely inhibited in concentration of 2500mg/L.When strain JQ1004 was cultivated at 30℃,pH 7.5,160rpm with the initial ammonium of 100,300,500,700,1000,1500,2000mg/L,the maximum specific growth rates were 0.251,0.308,0.286,0.243,0.197,0.115,0.088h^-1,and the corresponding ammonium specific removal rates reached 1.335,1.906,1.859,1.759,1.562,1.286,0.965g/g (DCW·d),respectively.Due to the inhibition of free ammonia and high-strength concentration of ammonium,the specific growth rate and degradation rate of ammonia increased at first and decreased with the increase of initial concentration of ammonia nitrogen (free ammonia).Three kinetic models (Haldane,Yano,Aiba) were fitted well to the experimental growth kinetic data with the correlation coefficients (R²) of 0.9944,0.9983 and 0.9929.For Haldane model,the values of μ_max,K_s,and K_i were 2.604h^-1,22.57mg/L,and 1445.31mg/L,respectively.The large values of K_i,far greater than that of autotrophic nitrifiers or anaerobic ammonium-oxidizing bacteria,indicated that JQ1004 had good tolerance against high ammonium concentrations.Besides,the specific growth rate reached a maximum value of 0.583h^-1 when the concentration of free ammonia was 5.436mg/L.These results indicated possible future applications of JQ1004 in removing nitrogen and organic carbon from high-strength ammonium wastewater.