Super diluted mixture alkali (SDMA) pretreatment for cornstalk anaerobic Digestion: A green strategy for High-Solid biogas production

Abstract

Biogas production from lignocellulose by anaerobic digestion has made significant progress lately. However, the bioconversion of lignocellulose is still hindered by its recalcitrant and heterogeneous structure. To overcome this challenge, a novel method of super diluted mixture alkali (SDMA) pretreatment was developed to enhance the biogas production from cornstalk in high-solid anaerobic digestion. The cornstalks treated with 2 g/L NH3 and 1 g/L NaOH achieved a cumulative methane yield of 241.50 mL/g VS, which was 184.65 % and 55.6 % higher than that of the untreated and 2 % NaOH treated cornstalks, respectively. The system stability was verified by a scale-up experiment in a 10 L bioreactor. Remarkably, the entire process does not generate any wastewater or chemical pollution. Moreover, the resultant biogas slurry could be directly applied as a concentrated bio-fertilizer. The findings are potentially beneficial for the development of the second-generation biogas industry from lignocellulosic biomass, which can provide both clean and economical bioenergy.