Cervantes Francisco J, Gutiérrez Claudia H, López Kitzia Y, Estrada-Alvarado María Isabel, Meza-Escalante Edna R, Texier Anne-Claire, Cuervo Flor, Gómez Jorge
Departamento de Ciencias del Agua y del Medio Ambiente, Instituto Tecnológico de Sonora, Av. 5 de Febrero 818 Sur, Cd. Obregón, SON 85000, Mexico.
Biodegradation. 2008 Apr;19(2):235-46. doi: 10.1007/s10532-007-9130-x. Epub 2007 May 30.
The capacity of two anaerobic consortia to oxidize different organic compounds, including acetate, propionate, lactate, phenol and p-cresol, in the presence of nitrate, sulfate and the humic model compound, anthraquinone-2,6-disulfonate (AQDS) as terminal electron acceptors, was evaluated. Denitrification showed the highest respiratory rates in both consortia studied and occurred exclusively during the first hours of incubation for most organic substrates degraded. Reduction of AQDS and sulfate generally started after complete denitrification, or even occurred at the same time during the biodegradation of p-cresol, in anaerobic sludge incubations; whereas methanogenesis did not significantly occur during the reduction of nitrate, sulfate, and AQDS. AQDS reduction was the preferred respiratory pathway over sulfate reduction and methanogenesis during the anaerobic oxidation of most organic substrates by the anaerobic sludge studied. In contrast, sulfate reduction out-competed AQDS reduction during incubations performed with anaerobic wetland sediment, which did not achieve any methanogenic activity. Propionate was a poor electron donor to achieve AQDS reduction; however, denitrifying and sulfate-reducing activities carried out by both consortia promoted the reduction of AQDS via acetate accumulated from propionate oxidation. Our results suggest that microbial reduction of humic substances (HS) may play an important role during the anaerobic oxidation of organic pollutants in anaerobic environments despite the presence of alternative electron acceptors, such as sulfate and nitrate. Methane inhibition, imposed by the inclusion of AQDS as terminal electron acceptor, suggests that microbial reduction of HS may also have important implications on the global climate preservation, considering the green-house effects of methane.
评估了两个厌氧菌群在以硝酸盐、硫酸盐和腐殖质模型化合物蒽醌 - 2,6 - 二磺酸盐（AQDS）作为终端电子受体的情况下，氧化不同有机化合物（包括乙酸盐、丙酸盐、乳酸盐、苯酚和对甲酚）的能力。在所研究的两个菌群中，反硝化作用显示出最高的呼吸速率，并且对于大多数降解的有机底物而言，反硝化作用仅在培养的最初几个小时内发生。在厌氧污泥培养中，AQDS和硫酸盐的还原通常在完全反硝化之后开始，或者在对甲酚的生物降解过程中甚至同时发生；而在硝酸盐、硫酸盐和AQDS的还原过程中，产甲烷作用并未显著发生。在所研究的厌氧污泥对大多数有机底物进行厌氧氧化的过程中，AQDS还原是优于硫酸盐还原和产甲烷作用的首选呼吸途径。相比之下，在用未实现任何产甲烷活性的厌氧湿地沉积物进行的培养中，硫酸盐还原比AQDS还原更具优势。丙酸盐是实现AQDS还原的不良电子供体；然而，两个菌群进行的反硝化和硫酸盐还原活动通过丙酸盐氧化积累的乙酸盐促进了AQDS的还原。我们的结果表明，尽管存在替代电子受体，如硫酸盐和硝酸盐，但在厌氧环境中有机污染物的厌氧氧化过程中，腐殖质（HS）的微生物还原可能发挥重要作用。将AQDS作为终端电子受体导致的甲烷抑制表明，考虑到甲烷的温室效应，HS的微生物还原对全球气候保护也可能具有重要意义。
