Recycling of Organic Wastes by Anaerobic Microbial Community

In light of the impending global energy crisis resulting from the depletion of non-renewable resources, the need for alternative and environmentally sustainable sources of power is becoming progressively evident. The utilization of wastewater has gained recognition as an essential and valuable resource for water reuse and energy conservation. Digestion under anaerobic conditions is a waste treatment method that is employed with the objective of mitigating the adverse impacts of waste on the biosphere. Catabolism of polymeric organic substances into simpler, chemically stabilized compounds, such as methane and CO2, is facilitated by the mutualistic behavior exhibited by different anaerobic microorganisms. The concurrent effluent treatment containing higher concentrations of organic compounds and electricity production are the primary factors motivating the modernization of microorganism-based fuel cells. Augmentation of electricity generation in MFCs necessitates optimization of operational parameters and the suppression of metabolic pathways that impede electricity production, i.e., methanogenesis. The formation of carbon dioxide and greenhouse gas (methane) by metabolizing the polymeric organic compound is facilitated by combinatorial efforts of distinct groups of microorganisms, namely acetogenic, syntrophic, fermentative, and methanogenic bacteria. Microorganisms employ diverse strategies to circumvent adverse conditions within anaerobic digesters, such as the competition between methane (methyl hydride)—producing bacteria and sulfate-reducing bacteria (SRB) for the utilization of identical substrates. Methanosarcina is capable of utilizing both acetoclastic and hydrogenotrophic pathways to facilitate the production of methane. The present chapter summarizes a comparative examination of the fundamental aspects pertaining to the digestion process of wastewater under anaerobic conditions. Additionally, it highlights the existing challenges and potential opportunities that can contribute to the advancement and expansion of this field. It also delves into the fundamental components involved in constructing microbial fuel cells and examines the influential factors that impact their operational effectiveness, including substrate oxidation, electron transfer, and internal resistance.