Change to biogas production in solid-state anaerobic digestion using rice straw as substrates at different temperatures

Abstract

This work investigated the effects of different temperatures on methane production, kinetics, and microbial communities during solid-state anaerobic digestion (SS-AD) using rice straw. The results indicated that thermophilic anaerobic digestion led to the faster methane production (13.74 L/kg) and a shorter biogas production cycle (34 days) than mesophilic anaerobic digestion (5.48 L/kg, 58 days). SS-AD under thermophilic conditions resulted in more intense lignocellulose degradation and better fitting results. The species of microorganisms did not differ when the temperature was altered; however, the abundances of various phyla, particularly Firmicutes, differed. Overall, the findings suggested that thermophilic SS-AD had higher methanogenic efficiency and dramatically altered the structure of the microbial community during solid-state anaerobic digestion. Moreover, a potential effective strategy for agricultural waste management by SS-AD was proposed.

Keywords: Anaerobic digestion; Mesophilic; Microbial community; Pretreatment; Thermophilic.