Pretreatment with rumen fluid improves methane production in the anaerobic digestion of corn straw

In this study, corn straw (CS) was pretreated with abattoir waste -rumen fluid (RF) at 39 C-degrees for 24 h and used to generate methane via anaerobic digestion (AD). The results showed that hydrolysis of CS was accelerated by rumen microorganisms, and the pretreated mixture showed a high soluble chemical oxygen demand (SCOD) content (7210 mg/L). The biogas yield and methane yield of pretreated CS (Pre -CS -D) were 332.1 +/- 5.7 mL/g VS and 214.3 +/- 13.4 mL/g VS, which were increased by 18.7% and 23.0% compared with the unpretreated CS (CSD), respectively. 16S rRNA high throughput results showed that the dominant flora in RF was quite different from traditional anaerobic sludge, and its high hydrolytic ability could be related to the high abundance of Clostridia (57.1%) and Bacteroidia (19.3%). In AD period, methanogenesis of CS and pretreated CS were mainly completed through hydrogenotrophic pathway by Methanobrevibacter, but RF pretreatment resulted in an enrichment of acetate -nutritive Methanosaeta. This study would provide insights into RF pretreatment of CS for enhanced biogas generation, which not only treats abattoir waste but also benefits the AD industry.