Alkyl polyglycoside addition could enhance the volatile fatty acids production from anaerobic digestion of food waste

Abstract

Producing chemicals from waste can be considered as a sustainable method to valorize residues. In this study, the effects of alkyl polyglycoside 06 (APG06) pretreatment on volatile fatty acid (VFA) production from food waste were determined by evaluating organic degradation, microbial reactions, enzyme activity, and functional enzyme species. When the dosage of APG06 was 9.45 g/L, the VFA production was the highest, reaching 16.7 g/L, with the main components of acetic acid and butyric acid. Total carbohydrate, and the concentrations of soluble protein and NH₄⁺-N were obtained 1.8 times, 1.2 times and 1.1 times of increment with APG06 addition. After adding APG06, acetate kinase and butyrate kinase activity was increased by 48 % and 140 %, respectively. Enterococcus and Terrisporobacter were enriched as the dominant genera with adding APG06, reaching 40 % and 12 %. In the metabolic pathway, glucose-6-phosphate isomerase, phosphoglycerate mutase and pyruvate dehydrogenase were significantly improved, increasing by 224 %,78 % and 115 %, respectively, leading to the 59 % increment on the total abundance of functional enzymes. The addition of APG06 mainly enhanced glucose isomerization and pyruvate metabolism steps, thus promoted the production of VFAs. The addition of APG06 not only optimizes microbial reactions and enzyme activities, but also promotes the enrichment of specific microbial populations, thereby enhancing the entire biodegradation process and providing new ideas for waste resource utilization, especially in bioenergy production.