Characterization of anaerobic digestion of Chinese cabbage waste by a thermophilic microorganism community

To enrich an effective Chinese cabbage waste-anaerobic digesting microorganism community, a mixture of cellulolytic microbial community, anaerobic straw-digesting sludge, and cow dung was loaded in a continuous stirred tank reactor, and the Chinese cabbage wastes were fed as carbon and nitrogenous sources. The methane conversion efficiency reached 235.6 mL/g VS after 37 days of operation. The average biogas producing yield was 452.6 mL/g VS with 10.1 g/(L day) of organic loading rate between day 213 and day 231. This microorganism community could effectively degrade Chinese cabbage waste and filter paper, and the weight losses were 72.6 ± 1.1% and 91.4 ± 2.4% in 7 days, respectively. This microorganism community was further analyzed by high-throughput sequencing of the 16S rRNA gene and shown to have abundant bacterial diversity, but poor archaeal diversity. Longilinea , Candidatus Cloacamonas , and Caldisericum were the top three classes of abundant bacterial community, and the proportional abundances were 7.0%, 5.5%, 3.6%, respectively. Methanothrix and Methanolinea dominated the methanogenic archaeal community and occupied 90.8% proportion of total archaeal abundance.