Cervantes F J, Vu-Thi-Thu L, Lettinga G, Field J A
Sub-department of Environmental Technology, Wageningen University, The Netherlands.
Appl Microbiol Biotechnol. 2004 Jun;64(5):702-11. doi: 10.1007/s00253-004-1564-z. Epub 2004 Feb 5.
The impact of humic acids and the humic model compound, anthraquinone-2,6-disulfonate (AQDS), on the biodegradation of carbon tetrachloride (CT) by anaerobic granular sludge was studied. Addition of both humic acids and AQDS at sub-stoichiometric levels increased the first-order rate of conversion of CT up to 6-fold, leading to an increased production of inorganic chloride, which accounted for 40-50% of the CT initially added. Considerably less dechlorination occurred in sludge incubations lacking humic substances. By comparison, very limited dechlorination occurred in sterile controls with autoclaved sludge. Accumulation of chloroform (1-10%) and dichloromethane (traces) also accounted for the CT converted. The accumulation of a chlorinated ethene, perchloroethylene (up to 9% of added CT), is also reported for the first time as an end-product of CT degradation. A humus-respiring enrichment culture (composed primarily of a Geobacter sp.) derived from the granular sludge also dechlorinated CT, yielding products similar to the AQDS-supplemented granular sludge consortium. The dechlorination of CT by the Geobacter enrichment was dependent on the presence of AQDS or humic acids, which were reduced during the assays. The reduced form of AQDS, anthrahydroquinone-2,6-disulfonate, was shown to cause the chemical reduction of CT when incubated in sterile medium. The results taken as a whole indicate that the formation of reduced humic substances by quinone-respiring microorganisms can contribute to the reductive dechlorination of CT.
研究了腐殖酸和腐殖质模型化合物蒽醌 - 2,6 - 二磺酸盐（AQDS）对厌氧颗粒污泥生物降解四氯化碳（CT）的影响。以亚化学计量水平添加腐殖酸和AQDS均使CT的一级转化速率提高了6倍，导致无机氯产量增加，无机氯占最初添加CT的40 - 50%。在缺乏腐殖质的污泥培养物中，脱氯现象明显减少。相比之下，在经高压灭菌的污泥无菌对照中，脱氯作用非常有限。氯仿（1 - 10%）和二氯甲烷（痕量）的积累也占了转化的CT的一部分。首次报道了一种氯化乙烯——全氯乙烯（高达添加CT的9%）作为CT降解的终产物积累。从颗粒污泥中获得的一种腐殖质呼吸富集培养物（主要由地杆菌属细菌组成）也能使CT脱氯，产生的产物与添加AQDS的颗粒污泥菌群相似。地杆菌富集培养物对CT的脱氯作用取决于AQDS或腐殖酸的存在，在试验过程中它们会被还原。当在无菌培养基中孵育时，AQDS的还原形式——蒽氢醌 - 2,6 - 二磺酸盐被证明会导致CT的化学还原。总体结果表明，醌呼吸微生物形成的还原态腐殖质有助于CT的还原脱氯。
