Study on chemical structure and mechanism of soil-phase electron mediator enhancing dechlorination activity of anaerobic microorganisms

固相胡敏素是土壤和沉积物中腐殖质的一部分，在任何pH条件下都不能溶解，它是厌氧联合体还原脱氯五氯苯酚的外部电子媒介。同一来源的腐植酸不支持五氯苯酚的脱氯。通过红外光谱、核磁共振、电子自旋共振、循环伏安等测试手段的分析，认为胡敏素的氧化还原反应中心为苯醌结构或铁-有机酸络合物。结果表明，在该富集菌中存在一种新的脱盐杆菌，它需要还原形式的胡敏素作为电子供体，五氯苯酚作为电子受体来进行有机卤化物的呼吸。人们认为电子直接从胡敏素转移到微生物细胞。

Solid-phase humin, a fraction of humic substances in soil and sediment which is not soluble in any pH condition, was found to function as external electron mediator for the anaerobic consortium reductively-dechlorinating pentachlorophenol. The humic acids extracted from the same source did not support the pentachlorophenol dechlorination. The redox-reacting centers of humin were suggested to be quinone structure or iron-organic acid chelating complex, based on the analyses using FT-IR, NMR, ESR, cyclic voltammetry. It was suggested that a novel Dehalobacter sp., requiring reduced-form humin as electron donor and pentachlorophenol as electron acceptor for the organohalide respiration, was present in the enriched consortium. It was considered that the electrons transfer from humin to microbial cells directly.