Impact of temperatures on microbial community structures of sewage sludge biological hydrolysis

This study investigated the biological hydrolysis performance at 35°C (BH35), 42°C (BH42), and 55°C (BH55) and the effect of temperatures on microbial communities of the hydrolyzed sludge. The results showed that the suspended solid reduction, volatile fatty acids (VFA) production, and biogas production increased with the BH temperatures. VFAs produced in the sludge BH included acetic acid, propionic acid, isobutyric acid, butyric acid, and isovaleric acid with the fractions of acetic acid increased with BH temperatures. The Illumina MiSeq sequencing analysis showed that the microbial taxonomic structures of the BH systems varied with BH temperatures. It was found that Acidaminobacter at 35°C, Proteiniphilum and Lutispor at 42°C, and Gelria at 55°C were the main protein fermenting bacteria genera, while the carbohydrate fermenting bacteria might belong to the genera of Macellibacteroides and Paludibacter at 35°C, Fronticella at 42°C, and Tepidimicrobium at 55°C.