Department of Environmental Engineering, University of Marmara, Kuyubasi, Istanbul, Turkey.
Environ Technol. 2010 Mar;31(3):295-305. doi: 10.1080/09593330903470677.
Cometabolic degradation of 1,2-dichloroethane (1,2-DCA) and its inhibitory impact on nitrification were investigated by the use of a mixed suspended-growth culture enriched for nitrifiers. 1,2-DCA was found to be cometabolically degradable by the nitrifier culture. This degradation rate was found to be dependent on the initial 1,2-DCA level. The first-order 1,2-DCA degradation rate constants ranged between 0.42 and 0.87 L (g VSS)(-1) h(-1). Increase in NH4-N utilization favoured cometabolic degradation of 1,2-DCA. The amount of 1,2-DCA degraded per unit mass of NH4-N strongly correlated with initial NH4-N and 1,2-DCA concentrations, ranging between 50 mg L(-1) and 200 mg L(-1) and 1600 microg L(-1) and 100,000 microg L(-1), respectively. The presence of 1,2-DCA caused inhibition of oxygen uptake and NH4-N utilization. In spite of the adverse effect of 1,2-DCA on the nitrifying biomass, the system had a high capacity for cometabolic removal of this compound even at inhibitory concentrations. 1,2-DCA had mainly mixed inhibitor characteristics, but at low concentrations (< 25,000 microg/L) it acted rather as a competitive inhibitor. The inhibition constants belonging to 1,2-DCA, K(ic) (the dissociation constant of the enzyme-inhibitory compound complex) and K(iu) (the dissociation constant of the enzyme-substrate-inhibitory compound complex) were determined to be 6000-8000 microg L(-1) and 188,000-200,000 microg L(-1), respectively.
采用富集硝化菌的混合悬浮生长培养物研究了 1,2-二氯乙烷（1,2-DCA）的共代谢降解及其对硝化作用的抑制影响。发现硝化菌培养物可共代谢降解 1,2-DCA。该降解速率取决于初始 1,2-DCA 水平。1,2-DCA 的一级降解速率常数在 0.42 至 0.87 L（g VSS）（-1）h（-1）之间。增加 NH4-N 的利用率有利于 1,2-DCA 的共代谢降解。单位质量 NH4-N 降解的 1,2-DCA 量与初始 NH4-N 和 1,2-DCA 浓度强烈相关，范围在 50 mg L（-1）至 200 mg L（-1）和 1600 μg L（-1）至 100,000 μg L（-1）之间。1,2-DCA 的存在抑制了氧摄取和 NH4-N 的利用。尽管 1,2-DCA 对硝化生物量有不利影响，但即使在抑制浓度下，该系统仍具有很高的共代谢去除该化合物的能力。1,2-DCA 主要具有混合抑制剂的特征，但在低浓度（<25,000 μg/L）下，它更像是一种竞争性抑制剂。1,2-DCA 的抑制常数 K(ic)（酶-抑制化合物复合物的离解常数）和 K(iu)（酶-底物-抑制化合物复合物的离解常数）分别确定为 6000-8000 μg L（-1）和 188,000-200,000 μg L（-1）。
