ABSTRACT
Simplified anaerobic digestion (SAD) of substrates facilitates microbial methanogenic pathways. In this study, a methane-producing microbial consortium from cow dung was enriched to determine the metabolism and metabolic pathway in the SAD of methanol. The results showed that methanol as a sole substrate produced 167 mL of methane at 10 days significantly higher than 58 mL, 17.6 mL, and 4 mL generated when methanol was combined with sodium formate, sodium formate alone, or sodium acetate. The relative abundance of Methanobacterium, Candidatus_Methanomethylophilus, Methanomassiliicoccus, and Methanosarcina was increased by 5.96 %, 3.77 %, 2.85 %, and 0.14 % in the methanol substrate of AD, respectively. Macrogenome sequencing indicates that methanol wasconverted into Methyl-CoM in the presence of Methanosarcina, which combines with Coenzyme B to produce methane. This study revealed that methanol is converted into methane by a simple pathway.
ABSTRACT
The present study investigated the degradation of un-pretreated wheat straw, corn stalk, and rice straw by a lignocellulose-degrading microbial consortium XDC-2. Following six days of cultivation, exocellular xylanase activities were 414.9, 491.9, and 335 U/mL, respectively. After 12 days, the rice straw had lost 39.71% of its weight, hemicellulose and cellulose losses of 78.27% and 14.08%, respectively. The total amount of volatile products reached a maximum on day six for rice straw degradation. The four major types of volatile products were acetic acid, propionic acid, butanoic acid, and glycerin, all of which would be suitable substrates for conversion to methanol by anaerobic digestion. According to PCR-DGGE analysis, XDC-2 remained stable during the degradation process of untreated lignocellulosic biomass. These results demonstrate the potential for further development and application of XDC-2; it is capable of degrading un-pretreated lignocellulosic materials, and has a low cost of operation.