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Biocatalysis mechanism for p-fluoronitrobenzene degradation in the thermophilic bioelectrocatalysis system: Sequential combination of reduction and oxidation

Wang, Yanfeng, Zhang, Xueqin, Feng, Huajun, Liang, Yuxiang, Shen, Dongsheng, Long, Yuyang, Zhou, Yuyang, Dai, Qizhou
Chemosphere 2016 v.159 pp. 44-49
anaerobic conditions, beta-Proteobacteria, biocatalysis, oxidation
To verify the potentially synthetic anodic and cathodic biocatalysis mechanism in bioelectrocatalysis systems (BECSs), a single-chamber thermophilic bioelectrocatalysis system (R3) was operated under strictly anaerobic conditions using the biocathode donated dual-chamber (R1) and bioanode donated dual-chamber (R2) BECSs as controls. Direct bioelectrocatalytic oxidation was found to be infeasible while bioelectrocatalytic reduction was the dominant process for p-Fluoronitrobenzene (p-FNB) removal, with p-FNB removal of 0.188 mM d−1 in R1 and 0.182 mM d−1 in R3. Cyclic voltammetry experiments confirmed that defluorination in the BECSs was an oxidative metabolic process catalyzed by bioanodes following the reductive reaction, which explained the 0.034 mM d−1 defluorination in R3, but negligible defluorination in controls. Taken together, these results revealed a sequentially combined reduction and oxidation mechanism in the thermophilic BECS for p-FNB removal. Moreover, the enrichment of Betaproteobacteria and uniquely selected Bacilli in R3 were probably functional populations for p-FNB degradation.