The average value of Meperidine hydrochloride Firmicutes proportion was 12% in three reactors. Firmicutes are well-known to be acetogenic and syntrophic bacteria that can degrade VFA, such as butyrate and its analogs. The prevalence of organisms belonging to Firmicutes suggested that these products are readily available due to the prior fermentation of these simple VFA and played a critical role in anaerobic digestion of FW, especially on the production of acetic acid, an essential step for methane production by acetoclastic methanogenic microorganisms. In addition, the relative abundances of other phyla including Proteobacteria, Spirochaetes and Tenericutes obviously increased with the feeding TS contents increasing. It has been suggested that they might play important roles in the degradation of FW. Proteobacteria are also involved in the first step of the degradation of organic wastes and they are important consumers of propionate, butyrate, and acetate. Spirochaetes are reported to ferment carbohydrates or amino acids into, mainly, acetate, H2 and CO2 and Tenericutes was found to be related with lignin utilization. In order to further compare the difference of bacterial communities in anaerobic digesters with different feeding TS contents, it is preferable to deconstruct the sequencing date at the subdivision level. Therefore, the relative abundance of each genus in three samples was calculated. The sequence distributions at genus level in each sample are shown in Table 4. A total of 17 genera were detected among which 7 genera with relative abundance of higher than 0.5% in at least one sample were screened as the abundant genera. Other genera were LWH-63 hydrochloride grouped into the minors. As mentioned in the previous section, lower proportions of population from the phylum Choroflexi were markedly detected in the reactors with higher TS contents. All sequences classified to phylum Choroflexi in three reactors were assigned to genus Anaerolineaceae and class Anaerolineae at class level, and the relative abundance of genus Anaerolineaceae decreased with increasing TS contents. Because all the characterized species of the class Anaerolineae are anaerobic bacteria that decompose carbohydrates via fermentation, the genus Anaerolineaceae seemed to be involved in carbohydrate decomposition in anaerobic digestion of FW.