The Implementation of Waste Biomass Substrates as Feedstock for the Production of Bio-Electricity Through Microbial Fuel Cells (MFCs): A Short Review

Abstract

Lignocellulosic biomass plays a pivotal role in sustainable energy production, with a focus on indirect biomass fuel cells (IDBFC) and  direct biomass fuel cells (DBFC). IDBFCs require the initial conversion of biomass into simpler forms like sugars, biogas, syngas, or biochar  for subsequent electricity generation. In contrast, DBFCs offer a more direct approach, generating electricity from biomass without  intermediate steps. Lignocellulosic biomass, composed of cellulose, lignin, and hemicellulose, has diverse applications, from bioethanol  to direct electricity generation. However, the complex composition of lignocellulosic compounds, including carbon, hydrogen, oxygen,  phosphorus, nitrogen, and sulfur, poses challenges for efficient enzymatic hydrolysis, a crucial factor in achieving high power density in  Microbial Fuel Cells (MFCs). MFCs use microorganisms to convert substrates into electricity, influenced by factors like substrate degradation  rate, circuit resistance, electron transfer rates, proton mass transfer, electrode materials, and operational conditions. The selection of proper  electrode materials is vital for optimising MFC performance. At the heart of MFC performance are electricigens, microorganisms facilitating  electron transfer from biomass to the anode through direct or indirect mechanisms. Direct electron transfer (DET), relying on physical  contact between microorganism membranes and the anode, is preferred for its efficiency and eco-friendliness. The paper also explores  the importance of nutrient supplements (macro and micro) in enhancing bio-methane production and process stability in agro-industrial  biogas mono-digestion plants. Nutrient balance significantly affects microbial generation time, degradation rates, and gas production  in anaerobic digestion processes. In conclusion, understanding the intricate interplay between lignocellulosic biomass energy fuel cells,  electricigens, and their performance factors is crucial for advanc