Abstract:
Radicalization in waste-to-energy systems are on the rise to meet human energy demands. Biogas generation from
kitchen wastes is one such scheme, though affected by poor yields and methane levels at low temperatures. In this research,
biocatalytic extracts with fermentative properties were hereby assessed on their potential to fasten these processes and increase
the biogas yield at ambient temperatures. The variations in kitchen waste substrate anaerobic parameters and elemental
composition as well as biogas yields and methane levels were monitored in a 28-day retention period. Three 40-liter batch and
unstirred bio-digesters containing biocatalysts Terminalia b., Acanthaceae spp. and a control setup were used. The results
indicated rapid saccharification rates in the samples with additives. Terminalia b. additives exhibited high volatile solids
hydrolysis rate of 98.3% followed by Acanthaceae spp. (50.8%) and control sample (29.4%). Similar trends were observed in
organic carbon reduction as the levels of nitrogen, phosphorus and sulfur linearly increased. The biocatalysts did not affect
substrate pH, volatile fatty acids and alkalinity levels. Terminalia b. sample produced 2.32 folds higher while Acanthaceae spp.
sample produced 1.375 folds higher than the control sample. Terminalia b. methane levels were highest (45.475±0.922%)
followed by the control sample (41.750±1.401) and Acanthaceae spp. sample (39.275±0.263%) after 28-day retention period at
19.5±0.5°C. Use of these biocatalysts in biofuel synthesis can thus optimize biogas production leading to greener economies.
