Mechanism that allows manno-oligosaccharide to promote cellulose degradation by the bacterial community and the composting of cow manure with straw

Abstract

The new sugar source manno-oligosaccharide can regulate the structure of the microbial community. This study investigated the effects of adding manno-oligosaccharide at four different levels (0, 0.1%, 0.5%, and 1% w/w compost) to composting cow manure and straw on lignocellulose degradation and the bacterial community. Adding 0.5% manno-oligosaccharide had the greatest effects on accelerating the composting process, reducing its toxicity, and improving the stability of the product. After composting for 25 days, adding 0.5% manno-oligosaccharide decreased the hemicellulose, cellulose, and lignin contents to 2.25%, 11.25%, and 7.07%, respectively, compared with those under CK. Manno-oligosaccharide promoted the degradation of lignocellulose by increasing the abundances of Thermobifida, Streptomyces, and Luteimonas. In addition, manno-oligosaccharide inhibited pathogenic bacteria and increased the abundances of functional genes related to metabolism. Finally, adding 0.5% manno-oligosaccharide mainly affected the degradation of lignocellulose by enhancing the C/N ratio and the abundances of Streptomyces and the secretion system during composting according to redundancy analysis.

Keywords: Aerobic composting; Bacterial community; Functional gene; Lignocellulose; Manno-oligosaccharide; Redundancy analysis.