Synergistic effect of yeast integrated with alkyl polyglucose for short-chain fatty acids production from sludge anaerobic fermentation

[Display omitted] •An effective strategy for boosting SCFA production from sludge AF was proposed.•The combination of yeast with APG benefited biodegradable substrate production.•A higher SCFA production was enabled by the synergistic effect of yeast with APG.•The underlying mechanisms of synergistic effect on SCFA generation were uncovered. An efficient strategy for short-chain fatty acid (SCFA) production from sludge anaerobic fermentation was proposed with the combination of yeast and alkyl polyglucose (APG). It revealed that the synergetic effect of yeast and APG could boost the SCFA concentration to the maximum value of 2800.34 mg COD/L within 9 days at 0.20 g/g suspended solids (SS) yeast and 0.20 g/g SS APG, which was significantly higher than that of its counterparts. Interestingly, the sludge solubilization, the biodegradability of fermentation substrate, as well as the acidification of hydrolyzed products, was evidently improved in the coexistence of APG and yeast. The activities of hydrolytic enzymes and acetate kinase were also stimulated, whereas the coenzyme F420 was inhibited. The synergetic effect of yeast and APG used in this work enriches the study of carbon resource recovery from sludge anaerobic fermentation.