Furthermore, the maximal VFAs accumulation at above situation was mainly due to the reasons that
sufficient soluble substrates for acidogenic bacteria and less VFAs consumed by other bacterias. And the
accumulation of VFAs was highly dependent on soluble protein and less influenced by soluble
carbohydrate. Also, in WAS thermophilic anaerobic digestion system, the solubilization was substantially
improved under optimal VFAs accumulation conditions.