Research progress on enhancement of methane production through direct interspecific electron transfer by conductive materials

Abstract:

Under anaerobic conditions, microorganisms produce methane (CH₄) through anaerobic metabolism. The derived anaerobic digestion technology realizes energy recovery. The key step of CH₄ production is to stimulate the effective electron transfer between fermentation bacteria and methanogens. Electroactive microorganisms can replace the traditional hydrogen/formate to achieve direct interspecific electron transfer, with higher electron transfer efficiency. The addition of conductive materials promotes direct interspecific electron transfer and increase the yield of CH₄, which is a more effective way to enhance the electron transfer. Based on the development and mechanism of direct interspecific electron transfer, carbon-based and iron-based conductive materials that promote direct interspecific electron transfer are comprehensively reviewed. The structural characteristics, electron transfer mechanism, enhanced CH₄ production and intermediate consumption by these materials are systematically summarized. This review aims to provides reference for the research of conductive materials promoting direct interspecific electron transfer, and to explore the possible research direction in future.