초록
<P><B>Abstract</B></P> <P>Lignocellulosic biomass is the most abundant natural resource with high biomethane potential. However, complex structure of lignocellulosic biomass has hampered the efficient utilization of this bioresource. Previous studies have investigated the overall anaerobic digestion performance of lignocellulosic biomass, but the individual participation of each lignocellulosic component during anaerobic digestion remained unclear. Thus, this study investigated the methane production characteristics of cellulose, hemicellulose, lignin and their mixtures along with the microbial communities involved in anaerobic digestion. The results showed that the biomethane potential of cellulose was higher than that of hemicellulose; however, hemicellulose was hydrolysed more quickly than cellulose, while lignin was very difficult to be digested. The higher concentrations of acetic, <I>n</I>-butyric and <I>n</I>-valeric acids hydrolysed from the hemicellulose resulted in a lower pH and more severe inhibition on methane production than that of cellulose, and the methanogenesis gradually recovered after pH adjustment. The co-digestion of cellulose and hemicellulose increased the methane yield and biodegradability compared to mono-digestions. The addition of lignin to cellulose brought more significant decrease in the methane yield of cellulose than that of hemicellulose. Substrate-related bacteria such as <I>Clostridium sensu stricto</I>, <I>Lutaonella</I>, <I>Cloacibacillus</I> and <I>Christensenella</I> showed higher relative abundance in cellulose digestate, and sugar-fermenting bacteria such as <I>Saccharofermentans</I>, <I>Petrimonas</I> and <I>Levilinea</I> were more rich in the digestate of hemicellulose. Moreover, methanogenic <I>Methanospirillum</I> and <I>Methanothrix</I> likely contributed to the methane production of cellulose, while aciduric methanogens from <I>Methanobrevibacter</I>, <I>Methanomassiliicoccus</I>, <I>Methanobacterium</I> and <I>Methanoculleus</I> contributed to that of hemicellulose. This study provides a deeper understanding of the mechanism in the bioconversion of lignocellulosic biomass during anaerobic digestion.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Anaerobic digestion characteristics of lignocellulosic components are described. </LI> <LI> Hemicellulose was hydrolysed and acidified more quickly than cellulose. </LI> <LI> The biomethane potential of cellulose was higher than that of hemicellulose. </LI> <LI> Co-digestion of cellulose and hemicellulose had a synergistic effect on methane yield. </LI> <LI> Lignin caused more severe inhibition on methane yield of cellulose than hemicellulose. </LI> </UL> </P>