Biocathodic Methanogenic Community in an Integrated
Anaerobic Digestion and Microbial Electrolysis System for Enhancement
of Methane Production from Waste Sludge
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<sup>3</sup> methane/(m<sup>3</sup> reactor*d) in the hybrid
reactor at room temperature, which was nearly double than that of
the control anaerobic reactor (0.0259 m<sup>3</sup> methane/(m<sup>3</sup>reactor*d)) without bioelectrochemical device. Microbial community
analysis revealed that hydrogenotrophic methanogen <i>Methanobacterium</i> dominated the cathode biofilm, which was the predominant contributor
to accelerate the methane production rate from WAS. While acetoclastic
methanogen <i>Methanosaeta</i> 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
