Oyster shells improve anaerobic dark fermentation performances of food waste: Hydrogen production, acidification performances, and microbial community characteristics

Anaerobic dark fermentation (DF) performances of food waste (FW) were investigated using oyster shells. The different amount oyster shells(6%-12%(w/w)) were added to the DF system of FW. The result showed that the H₂ production rate and cumulative H₂ production improved after addition oyster shells. The highest H₂ production rate and cumulative H₂ production of 8% oyster shells addition group were 8.4 mL/(gVS·h) and 88.2 mL/gVS, which were 11.7%-30.6% and 17.4%-52.9% higher than those of the other test groups. TVFAs production, especially acetic and butyric acids improved after addition oyster shells. The highest TVFAs production was 19291.4 mg/L for 8% oyster shells added group, which was 90.24% higher than that of the unadded group. For 8% oyster shells added group, Lactobacillales, Gallicola, and Bacteroides were the dominant species at genus levels. Thus, the addition of an appropriate amount oyster shells could improve H₂ production rate, cumulative H₂ production, promote buffering capacity, enhance TVFAs production.