Advancing Energy Recovery from Sugarcane Leaf via Two-Stage Anaerobic Digestion for Hydrogen and Methane Production: Impacts on Greenhouse Gas Mitigation and Sustainable Energy Production

This study aims to enhance energy recovery from sugarcane leaf (SCL) through two-stage anaerobic digestion (TSAD) for hydrogen and methane production. The influence of hydraulic retention time (HRT) on this process was investigated. Optimal conditions established through batch experiments (5% total solids (TS) (w/v) and rice straw compost inoculum) were applied in semi-continuous stirred tank reactors (CSTR-H₂ and CSTR-CH₄). Remarkably, the highest production rates were achieved with HRTs of 5 days for CSTR-H₂ (60.1 mL-H₂/L·d) and 25 days for CSTR-CH₄ (238.6 mL-CH₄/L·d). Microbiological analysis by 16s rRNA sequencing identified Bacillus as predominant in CSTR-H₂ followed by Lactobacillus and Clostridium. Utilizing SCL for TSAD could reduce greenhouse gas (GHG) emissions by 2.88 Mt-CO₂ eq/year, compared to open-field burning, and mitigate emissions from fossil-fuel-based power plants by 228 kt-CO₂ eq/year. This research underscores the potential of TSAD for efficient energy recovery and significant GHG emission reductions.