Biocathodic Methanogenic Community in an Integrated Anaerobic Digestion and Microbial Electrolysis System for Enhancement of Methane Production from Waste Sludge

摘要

Understanding the microbial community structure relative to enhancement of methane production from digestion of waste-activated sludge (WAS) coupled with a bioelectrochemical system is a key scientific question for the potential application of bioelectrochemistry in biogas production. Little has been known about the influence of electrode on the structure and function of microbial communities, especially methanogens in a bioelectrochemical anaerobic digestion (AD) reactor. Here, a hybrid reactor, which coupled bioelectrolysis and AD, was developed to enhance methane recovery from WAS. The methane production rate reached up to 0.0564 m(3) methane/(m(3) reactor*d) in the hybrid reactor at room temperature, which was nearly double than that of the control anaerobic reactor (0.0259 m(3) methane/(m(3)reactor*d)) without bioelectrochemical device. Microbial community analysis revealed that hydrogenotrophic methanogen Methanobacterium dominated the cathode biofilm, which was the predominant contributor to accelerate the methane production rate from WAS. While acetoclastic methanogen Methanosaeta was enriched in the sludge phase of all reactors, shifts of the microbial community structure of the biocathode was in significant correlation with the methane production. This study suggested a potential way to utilize a bioelectrochemical system with the regulated microbial community to enhance methane production from WAS.