Lignocellulose degradation, biogas production and characteristics of the microbial community in solid-state anaerobic digestion of wheat straw waste

Waste recycling is pivotal for deep space exploration or space habitation in life support systems (LSS) to enhance the material closure. This study investigated the enzymatic pretreatment and solid-state anaerobic digestion (SS-AD) of wheat straw as the major component of biomass waste in LSS for resource reclamation. Wheat straw compounds, such as cellulose, hemicellulose and lignin were significantly degraded after pretreatment with degradation at 37.47%, 46.96%, and 14.05%, respectively. SS-AD with the C/N ratio of 25 resulted in more intense lignocellulose degradation (74.20%) and more biogas yield (77.59 L/kg volatile solid) with 30 days digestion. The microbial community variation and diversity were analyzed that common fiber-degrading bacteria including Firmicutes, Bacteroidetes and Proteobacteria were dominant while the composition of the microbial genera shifted along with the digestion time. Moreover, a potential feasible strategy for biomass waste management in LSS by SS-AD was proposed.