Kim Young, Arp Daniel J, Semprini Lewis
Department of Civil, Construction, and Environmental Engineering, Oregon State University, Corvallis 97331-2302, USA.
Biotechnol Bioeng. 2002 Dec 5;80(5):498-508. doi: 10.1002/bit.10397.
Batch kinetic and inhibition studies were performed for the aerobic cometabolism of 1,1,1-trichloroethane (1,1,1-TCA), 1,1-dichloroethylene (1,1-DCE), and 1,1-dichloroethane (1,1-DCA) by a butane-grown mixed culture. These chlorinated aliphatic hydrocarbons (CAHs) are often found together as cocontaminants in groundwater. The maximum degradation rates (k(max)) and half-saturation coefficients (K(s)) were determined in single compound kinetic tests. The highest k(max) was obtained for butane (2.6 micromol/mg TSS/h) followed by 1,1-DCE (1.3 micromol/mg TSS/h), 1,1-DCA (0.49 micromol/mg TSS/h), and 1,1,1-TCA (0.19 micromol/mg TSS/h), while the order of K(s) from the highest to lowest was 1,1-DCA (19 microM), butane (19 microM), 1,1,1-TCA (12 microM) and 1,1-DCE (1.5 microM). The inhibition types were determined using direct linear plots, while inhibition coefficients (K(ic) and K(iu)) were estimated by nonlinear least squares regression (NLSR) fits to the kinetic model of the identified inhibition type. Two different inhibition types were observed among the compounds. Competitive inhibition among CAHs was indicated from direct linear plots, and the CAHs also competitively inhibited butane utilization. 1,1-DCE was a stronger inhibitor than the other CAHs. Mixed inhibition of 1,1,1-TCA, 1,1-DCA, and 1,1-DCE transformations by butane was observed. Thus, both competitive and mixed inhibitions are important in cometabolism of CAHs by this butane culture. For competitive inhibition between CAHs, the ratio of the K(s) values was a reasonable indicator of competitive inhibition observed. Butane was a strong inhibitor of CAH transformation, having a much lower inhibition coefficient than the K(s) value of butane, while the CAHs were weak inhibitors of butane utilization. Model simulations of reactor systems where both the growth substrate and the CAHs are present indicate that reactor performance is significantly affected by inhibition type and inhibition coefficients. Thus, determining inhibition type and measuring inhibition coefficients is important in designing CAH treatment systems.
进行了丁烷培养的混合菌群对1,1,1 - 三氯乙烷（1,1,1 - TCA）、1,1 - 二氯乙烯（1,1 - DCE）和1,1 - 二氯乙烷（1,1 - DCA）好氧共代谢的批次动力学和抑制研究。这些氯代脂肪烃（CAHs）在地下水中常作为共污染物同时存在。在单一化合物动力学试验中测定了最大降解速率（k(max)）和半饱和系数（K(s)）。丁烷的k(max)最高（2.6微摩尔/毫克TSS/小时），其次是1,1 - DCE（1.3微摩尔/毫克TSS/小时）、1,1 - DCA（0.49微摩尔/毫克TSS/小时）和1,1,1 - TCA（0.19微摩尔/毫克TSS/小时），而K(s)从高到低的顺序为1,1 - DCA（19微摩尔）、丁烷（19微摩尔）、1,1,1 - TCA（12微摩尔）和1,1 - DCE（1.5微摩尔）。使用直接线性图确定抑制类型，同时通过对已确定抑制类型的动力学模型进行非线性最小二乘回归（NLSR）拟合来估计抑制系数（K(ic)和K(iu)）。在这些化合物中观察到两种不同的抑制类型。直接线性图表明CAHs之间存在竞争性抑制，并且CAHs也竞争性抑制丁烷的利用。1,1 - DCE是比其他CAHs更强的抑制剂。观察到丁烷对1,1,1 - TCA、1,1 - DCA和1,1 - DCE转化的混合抑制。因此，竞争性抑制和混合抑制在这种丁烷培养物对CAHs的共代谢中都很重要。对于CAHs之间的竞争性抑制，K(s)值的比率是观察到的竞争性抑制的合理指标。丁烷是CAH转化的强抑制剂，其抑制系数远低于丁烷的K(s)值，而CAHs是丁烷利用的弱抑制剂。对同时存在生长底物和CAHs的反应器系统进行的模型模拟表明，反应器性能受到抑制类型和抑制系数的显著影响。因此，确定抑制类型和测量抑制系数对于设计CAH处理系统很重要。
