83 / 2021-06-30 18:16:27

Anaerobic digestion of fruit waste for high-rate volatile fatty acids production: performance and microbial community characteristics

Volatile fatty acids; Anaerobic digestion; Organic loading rate; Fruit waste; microbial community

This study aimed to explore high-rate volatile fatty acids production potential from undiluted fruit wastes via anaerobic digestion, and the long-term performance and microbial community characteristics at different organic loading rates (OLRs) was monitored for 262 days. The results showed that stepwise increase of OLR from 8 to 24 g volatile total solids (VTS)/L/d could maintain a high concentration of VFAs productions and the highest concentration of 61.90 g COD/L was achieved at OLR of 14 g VTS/L/d. Acetate (31.67-44.47 %) and propionate (27.26-57.67 %) were dominant from OLRs 8 to 10 g VTS/L/d, while propionate concentration decreased with the increase of butyrate (14.03-68.34 %) from OLRs 12 to 24 g VTS/L/d. The microbial community dynamics analysis revealed that the relative abundance of Firmicutes and Actinobacteriota were dominant at the phylum level. At the genus level, the high abundance of Lactobacillus (24.67-43.93 %) was observed, followed by Clostridium_sensu_stricto_12 (14.19-43.32 %). Spearman’s correlation analysis showed close relationship between microbial community structure and environmental factors; genus Olsenella showed positive relationship with SCOD and OLR, and the latter was negatively correlated with genus Acidipropionibacterium.