Optimizing biogas yields from chicken manure: A comparative study of Inocula in batch anaerobic digestion

Abstract This study evaluates the hypothesis that inoculum origin significantly influences methane yield, volatile fatty acid (VFA) dynamics, and key indicators of process stability (TS, COD, and TAN) during batch anaerobic digestion of chicken manure leachate. Readily degradable fractions of chicken manure were extracted by the leaching method and used as a substrate for digestion. Two industrial inocula were investigated: effluent from a palm oil mill anaerobic digester (Inoculum I) and effluent from a food waste anaerobic digester (Inoculum II). Batch digestion was conducted under mesophilic conditions (35°C–38°C) with pH maintained at 6.8–7.2. The total VFA during the acidogenic‐methanogenic transition decreased by 8.54 g/L with Inoculum I, while Inoculum II showed the highest reduction (14.78 g/L), indicating more efficient VFA consumption toward methane formation. Inoculum II achieved a higher methane composition (52–68%) and a cumulative methane yield of 159.4 mL CH 4 /g VS, compared to 74.6 mL CH 4 /g VS for Inoculum I. Total biogas yield reached 403 mL/g VS with Inoculum II and 234.1 mL/g VS with Inoculum I. These findings confirm that inoculum origin governs digestion kinetics and stability, demonstrating the potential of food‐waste‐derived inoculum to optimize methane generation and VFA utilization in chicken‐manure‐based anaerobic digestion systems.