Competition for H2 between sulfate reduction and dechlorination in butyrate-fed anaerobic cultures
Competition for H2 between sulfate reduction and dechlorination in butyrate-fed anaerobic cultures
复制标题
DOI：
10.1016/j.procbio.2007.11.006
复制
发表时间：
2008-02-01
影响因子：
4.4
通讯作者：
Tandoi, Valter
中科院分区：
文献类型：
--
作者：
Aulenta, Federico;Beccari, Mario;Tandoi, Valter
在这项研究中，研究了两种不同的微生物培养物（一种用来自意大利威尼斯工业区的泻湖沉积物构建，另一种用来自意大利Rho氯化溶剂污染场地的含水层材料构建）对全氯乙烯（PCE）、1，1，2，2-四氯乙烷（TeCA）及其与丁酸盐作为主要电子供体的混合物（即，释放H-2的底物）在存在和不存在硫酸盐的情况下，硫酸盐是一种普遍存在的地下水成分。在所有的测试条件下，硫酸盐的存在对还原脱氯速率有不利影响。这种效应最有可能是由于存在于培养物中的硫酸盐还原群体对H-2的快速和竞争性利用。事实上，在所有含硫酸盐的设置中，在丁酸盐降解过程中通常观察到0.7-2.9 nmol L-1范围内的“稳态”溶解H-2浓度。在如此低的H-2水平下，脱氯过程的速率受到电子供体可用性的限制。然而，尽管事实上在所有含硫酸盐的设置中H-2水平几乎相同（即，0.7-2.9 nmol·L ~（-1）），脱氯活性的降低程度主要取决于供试培养物和投加的氯代化合物（初始脱氯率降低18%至95%以上）。本研究的结果表明，硫酸盐还原剂和脱氯剂之间的竞争H2的程度，并反过来在污染场地的电子供体除了的影响，强烈依赖于相对动力学的H-2-释放和H-2-消耗反应，不能简单地预测先验的基础上的差异H-2阈值浓度值之间的竞争性代谢。(c)2007爱思唯尔有限公司保留所有权利。
In this study two different microbial cultures (one constructed with lagoon sediments from an industrial area in Venice, Italy and the other with aquifer material from a chlorinated solvent-contaminated site in Rho, Italy) were investigated for their ability to dechlorinate perchloroethylene (PCE), 1,1,2,2-tetrachloroethane (TeCA) and their mixtures with butyrate as the primary electron donor (i.e., the H-2-releasing substrate) in the presence and in the absence of sulfate, an ubiquitous groundwater component. In all the tested conditions, the presence of sulfate had a detrimental effect on the rate of reductive dechlorination. This effect was most likely due to the rapid and competitive utilization of H-2 by the sulfate-reducing populations present in the cultures. Indeed, in all sulfate-containing setups a "steady-state" dissolved H-2 concentration in the range of 0.7-2.9 nmol L-1 was typically observed during butyrate degradation. At such low H-2 levels the dechlorination process was rate-limited by the electron donor availability. However, in spite of the fact that in all the sulfate-containing setups the H-2 level was nearly the same (i.e., 0.7-2.9 nmol L-1) the extent of reduction of dechlorinating activity greatly depended on the culture tested and the chlorinated compound administrated (from 18% to over 95% reduction of initial dechlorination rate). The results of this study indicate that the extent of competition for H2 between sulfate-reducers and dechlorinators, and in turn the impact of an electron donor addition at a contaminated site, are strongly dependent on the relative kinetics Of H-2-releasing and H-2-consuming reactions and cannot be predicted a priori simply based on differences in H-2 thresholds concentration values among competitive metabolisms. (c) 2007 Elsevier Ltd. All rights reserved.