Establishing practical strategies to run high loading corn stover anaerobic digestion: Methane production performance and microbial responses

Abstract

It is significant to understand corn stover (CS) in anaerobic digestion (AD) under high organic loadings. A semi-continuous mesophilic (37 ± 1 °C) CS AD was conducted in this study with increasing loadings. The initial total solids (TS) gradually increased with 1% gradient at every 10 days from 8% to 15% until the system was acidified. Adding different ratios of cattle manure (CM) (20%, 30% and 40% (v/v)) to rescue this system back to a stable operation was adopted. The diversity of bacteria and archaea was analyzed by 16S rRNA gene sequencing technology. The results showed that when loading TS content was increased to 15%, AD system was acidized with pH value of 5.13. 30% of CM was the optimal ratio to recover biogas production. High abundance (31.07%) of Bathyarchaeota was first found in AD system. Acidification of high loading CS AD can be highly correlating with bacterial community, specially Clostridium and Caproiciproducens.

Keywords: Acidification; Anaerobic digestion; Corn stover; Microbial diversity; Organic loading.