Pretreatment of lignocellulosic biomass and biogas production from a microbial consortium recovered from soil litter and termite gut

Biogas is a renewable energy source produced through the anaerobic digestion of organic waste. Access by microbial enzymes can be facilitated if the lignocellulosic material undergoes pretreatment. Leaf litter and termite guts can be promising sources of enzyme-producing microorganisms for this purpose. Fungi and bacteria recovered from soil litter and termite guts were screened for enzymatic activities and used as a consortium in a pretreatment of sugarcane bagasse to improve biogas production. Forty fungi and nine bacteria were isolated. From this, nine filamentous fungi and nine bacteria produced at least two of the enzymatic activities. The highest values ​for laccase, lignin peroxidase, and manganese peroxidase were 0.16, 1,863.80, and 1,737.27 U L⁻¹, respectively. For cellulase and xylanase were 13.52 and 64.24 U mL⁻¹, respectively. Talaromyces mycothecae BR04, Aspergillus versicolor BR14, Rossellomorea marisflavi CPM2, Bacillus subtilis CPM6, and Priestia megaterium CPM18 were used in the pretreatment of sugarcane in semi-solid fermentation for 14 days at 28 °C, due to improved performance in enzymatic activities and compatibility assays. Sugarcane bagasse + bacteria (SCB + B) treatment exhibited the highest total accumulated biogas production, reaching 66.95 NL kg^{- 1} VS, compared to SCB, demonstrating that microbial pretreatment improved biogas production. Fungi and bacteria isolated from leaf litter and termite guts produce enzymes involved in biogas production. The use of microbial consortia in the pretreatment of lignocellulosic biomass can enhance biogas production.