Multi-hydrolytic enzyme accumulation and microbial community structure of anaerobic co-digestion of food waste and waste activated sludge.

The accumulation of multi-hydrolytic enzyme through anaerobic co-digestion of waste activated sludge (WAS) and food waste (FW) was studied by regulating temperature, pH, and the mass ratio of FW to WAS (F/W). Experimental results showed that temperature had a profound effect on the activity of enzyme and the most suitable temperature for the accumulation of amylase and protease was 37℃ and 50℃, respectively. The highest activity of amylase and protease accumulated reached 10.29 and 19.23 U/mL at F/W ratio of 2:1. The addition of anaerobic co-digestion solution enriching protease and amylase had positive effects on the hydrolysis of WAS. In addition, the Illumina high-throughput sequencing demonstrated that the bacterial diversity decreased, but the bacterial abundance increased during co-digestion of WAS and FW process . The predominant strains for secreting amylase were Lactobacillus and Clostridium-sensu-strito-1, and Aeromonas were the dominant strains for secreting protease.