Novel insights into the estimation of theoretical methane yield from lignocellulosic waste based on formula modification

Boyle’s equation has been widely utilized for the computation of the theoretical methane yield to evaluate the biodegradability of lignocellulosic waste via anaerobic digestion. However, this equation neglects the fact that the lignin in lignocellulosic waste is hardly converted to biogas during anaerobic digestion, causing the erroneous estimation of biodegradability. In this study, a novel equation modified from Boyle’s equation proposed through theoretical derivations, and its reliability was validated using machine learning based on the experimental methane yield and chemical compositions data of 144 lignocellulosic wastes. The results showed that the average theoretical methane yield calculated from modified equation was 11.54% lower than that from Boyle’s, while the average biodegradability calculated from modified quation was 15.26% higher than that from Boyle’s. More importantly, the biodegradability from the modified quation was estimated more accurately, indicating a higher correlation with the chemical composition. The modified quation could provide a universal and reliable estimation of the theoretical methane yield and biodegradability of lignocellulosic waste, which not only guarantees the accuracy of evaluating the digestibility of lignocellulosic waste in lab-scale anaerobic digestion tests but also offers a more precise assessment of methane production efficiency and economy in the industrial anaerobic digestion process.