Steering ensiling process to maximize methane production of wilted maize straw: The role of exogenous carbon sources

Water-soluble carbohydrate (WSC) is essentioal for ensiling process which is an effective way to preserve biomass and improve biodegradability for biogas recovery. In this study, the effects of pentoses (xylose and arabinose), hexoses (glucose and fructose), and sucrose on maize straw ensiling were evaluated to maximize methane yield. Distinct consumption kinetics were observed among carbon sources during early ensiling, with faster rates detected for hexoses than for pentoses. Enhanced organic acid production and enrichment of lactic acid bacteria were observed following carbon supplementation; however, distinct microbial communities were established with different carbon sources, resulting in divergent fermentation characteristics. Among the tested carbon sources, a relatively higher pH environment (pH ≈ 4.7) was maintained with arabinose supplementation, favoring butyrate-associated fermentation. This fermentation pattern was associated with lignocellulosic transformation and contributed to the highest methane yield (309.6 L/kg ODM) and net energy recovery (8.3%). These findings provide preliminary experimental evidence for understanding the role of carbon source type in enhancing methane production from wilted maize straw.