Co-ensiling of rice straw and distillers grains to increase methane production and maximise energy output

• Published in: Bioresource technology 2023-10, Vol.386, p.129496-129496, Article 129496
• Main Authors: Luo, Xuan, Liu, Yuhuan, Lei, Luyao, Shen, Jiali, Zhang, Qi, Wang, Yunpu, Ruan, Roger, Cui, Xian
• Format: Article
• Language: English
• Subjects: Anaerobic digestion; Biodegradability; Biomass; Ensiling quality
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.129496

[Display omitted] •Effects of DGs and RS co-ensiling on methane production were studied.•The high amount of DGs enhanced lactic acid fermentation and the ensiling quality.•Low amounts of DGs enhance biodegradation but limit energy conversion.•High amounts of DGs significantly improve energy conversion and CH4 yields.•Organic matter preservation of ensiling is essential for methane production. High organic matter preservation during ensiling promotes material conversion and energy output. In this study, the effects of co-ensiling distillers grains and rice straw on methane production was evaluated, as distillers grains are highly acidic. For co-ensiling, distillers grains and rice straw were mixed to produce methane at five carbon/nitrogen (C/N) ratios. RD20 (C/N20) and RD25 (C/N25) were defined as high-distillers-grain groups and other mixed groups as low-distillers-grain groups. The results showed that Lactobacillus was enriched in RD25, with the highest lactic acid content reaching 54.0 g/kg of dry matter. The pH and organic dry matter loss of RD25 were lower than those of low-distillers-grain groups, but the result for lignocellulose degradation rate was reversed. An 8.6% increase in methane yield and 7.9% increase in energy output were achieved in RD25. Ensiling-anaerobic digestion systems of C/N25 provide high organic matter preservation and energy output.