Carbon cloth stimulates direct interspecies electron transfer for phenol biodegradation

In this study, we investigated the effect of carbon cloth (CC) on the anaerobic process of phenol biodegradation, by stimulating direct interspecies electron transfer (DIET) combined with adsorption process. Phenol biodegradation was examined over three sequential batches using bioreactors consisting of 100 mL syringes. Three experiment sets with different types of activated carbon (AC) were examined. Addition of all types AC to the bioreactors significantly enhanced methane production rate (two-fold higher compared to control sets without AC).Adsorption isotherms and kinetics suggest that the enhancement of phenol biodegradation may occur through a synergetic adsorption-biodegradation process, where a significant and fast reduction of phenol adsorption contributes to decreasing the inhibition effect, followed by biological anaerobic digestion (AD) of the adsorbed phenol by stimulating DIET process. The optimal concentration for carbon cloth single weave (CCSW) promoted the DIET and adsorption processes. High-throughput sequencing of microbial communities revealed that CCSW facilitated the enrichment of syntrophic bacterial groups (Rikenellae, Syntrophorhabdaceae, Gracilibacteraceae, and DTU014), and also archaea (Methanosaetaceae and Methanosaetaceae), which are known to be key players in DIET processes and promote phenol degradation. This work demonstrates how CC stimulates DIET processes in anaerobic bioreactors, to enhance biodegradation of phenol at high concentration.

本研究通过结合吸附过程与刺激种间直接电子传递（direct interspecies electron transfer, DIET）的方式，探究了碳纤维布（carbon cloth, CC）对苯酚生物降解厌氧过程的影响。本研究采用由100 mL注射器构成的生物反应器，通过3组序批批次实验考察苯酚的生物降解性能，并设置了3组搭载不同类型活性炭（activated carbon, AC）的实验组。向生物反应器中添加所有类型的活性炭，均可显著提升产甲烷速率（较未添加活性炭的对照组高出2倍）。吸附等温线与动力学分析结果显示，苯酚生物降解的强化可通过吸附-生物降解协同过程实现：苯酚吸附量的快速显著降低可缓解其抑制效应，随后通过刺激DIET过程，使吸附态苯酚发生厌氧消化（anaerobic digestion, AD）。单织碳纤维布（carbon cloth single weave, CCSW）的最优浓度可同时促进DIET与吸附过程。微生物群落高通量测序结果表明，CCSW可促进互营细菌类群（Rikenellae、Syntrophorhabdaceae、Gracilibacteraceae及DTU014）与古菌（Methanosaetaceae和Methanosaetaceae）的富集，上述菌群均为DIET过程的关键功能菌群，可有效促进苯酚降解。本研究阐明了碳纤维布如何通过厌氧生物反应器内的DIET过程，强化高浓度苯酚的生物降解。