Optimizing biomethanation of a lignocellulosic biomass using indigenous microbial-cellulases systems

Abstract

Studies on enhancing biomethanation were performed to ascertain whether amending lignocellulosic biomass waste with indigenous microbial-cellulases systems will improve biomethane output. To evaluate this, gastrointestinal contents of slaughtered beef cattle were treated with inocula derived from the guts of giant African land snail ( Archachatina marginata ) and worker termites ( Coptotermes formosanus ), individually as well as combined. The fed-batch method operating at prevailing ambient room temperatures (30 ± 2EC) for a hydraulic retention time (HRT) of 60 days was adopted. Feedstock slurry without amendment, amended with Archachatina marginata -derived inoculum, amended with Coptotermes formosanus -derived inoculum, and amended with Archachatina marginata : Coptotermes formosanus (50 : 50%) mixed inocula yielded cumulative biomethane of 65.26 ml/g VS, 63.21 ml/g VS, 125.99 ml/g VS, and 97.16 ml/g VS, respectively. Physicochemical analysis of feedstock and digestates revealed increased reductions in lignin, hemicelluloses, and celluloses (lignocelluloses) in trials amended with microbial-cellulases systems. This study revealed that among the experiments assayed, the trial amended with the cellulases system from Coptotermes formosanus yielded the highest cumulative biomethane.

Keywords

• anaerobic digestion
• biogas
• bio-augmentation
• recalcitrant biowaste