Influence of the substrate to inoculum ratio on the methane yield from the batch anaerobic digestion of river tamarind (Leucaena leucocephala) and Guinea grass (Panicum maximum)

The substrate to inoculum ratio (SIR) is an often overlooked parameter in the determination of the methane potential of a substrate.In this article we highlight the importance of the SIR, in the determination of the biochemical methane potential of two substrates, Guinea grass (Panicum maximum) and river tamarind (Leucaena leucocephala). Additionally, the results of this method not only give the specific methane potential, but also the optimum substrate to inoculum ratio, which is an important parameter for bioreactor start-up.The specific methane volumes of the two substrates are, 148 mL/gDM and 250 mL/gDM for the river tamarind and Guinea grass, respectively, with optimum substrate to inoculum ratios of 0.055 and 0.035, respectively. (c) 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.