Multiple hydrolyses of rice straw by domesticated paddy soil microbes for methane production via liquid anaerobic digestion

• Published in: Bioresource technology Vol. 354; p. 127184
• Main Authors: Wang, Jingjing, Cao, Leipeng, Liu, Yuhuan, Huang, Zhenghua, Li, Congmiao, Wu, Daishe, Ruan, Roger
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2022
• Subjects: Liquid anaerobic digestion; Methane; Multiple hydrolyses; Paddy soil microbe; Rice straw; Methane; Multiple hydrolyses; Liquid anaerobic digestion; Paddy soil microbe; Rice straw
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2022.127184

[Display omitted] •Multiple hydrolyses of rice straw by domesticated paddy soil microbes were studied.•Maximum VFA and TOC were obtained after 3 hydrolyses with a 45% inoculation ratio.•Degrade rate of rice straw and CH4 yield were 82.2% and 462.1 mL/g VS, respectively.•The cumulative CH4 production curve fitted well with the modified Gompertz model. The aim of this study was to investigate the hydrolysis of rice straw (RS) using domesticated paddy soil microbes (DPSMs) with swine wastewater (SW) as the nitrogen source and the multiple hydrolyses for CH4 production via liquid anaerobic digestion (L-AD). Three hydrolyses of RS with a 45% inoculation ratio (IR) under the conditions of a carbon/nitrogen ratio (C/N ratio) of 40, temperature of 37 °C, inoculum/substrate ratio (I/S ratio) of 2:1, and immersion depth of 6.0 cm were optimal, attaining maximum volatile fatty acids (VFAs) after five days, possibly owing to the synergistic effect of aerobic microbes (Firmicutes and Actinomycetes) and anaerobic microbes (Bacteroidetes and Acidobacteria). After three hydrolyses, the degradation rates of hemicellulose, cellulose, and lignin in RS were 88.45%, 83.19% and 70.09%, respectively. The accumulative CH4 production reached 462.11 mL/g VS after three hydrolyses, and its curve fitted well with the modified Gompertz model (R2 > 0.984).