Hydrolytic Enzyme Produced From Co-digestion Of Food Waste And Waste Activated Sludge And Microbial Community Struc Ture

In this paper,the anaerobic digestion of food waste(FW)and waste activated sludge(WAS)are used to produce hydrolytic enzyme.After adding hydrolytic enzyme from co-fermentation of FW and WAS into fermentation system of WAS,the hydrolysis of WAS were accelerated,so as to promote the whole reaction.Experiment was carried out in simple fermentation device to attained the optimal parameter of enzyme production by adjusting temperature,pH and the mass ratio of FW to WAS,with the simulated FW and WAS from municipal sewage plant as substrate.In addition,the next-generation DNA sequencing techniques(Ilumina sequencing)were used to detect the microbial community in enzyme-forming process and the second growth with the addition of enzyme products into WAS.The index such as Total suspended solids(TSS),Volatile suspended solids(VSS),soluble COD(SCOD),soluble protein,soluble carbohydrate and enzyme activity were measured to monitor the hydrolysis of the sample.Enzyme activity and microbial community structure provide a feasibility of enzyme production of co-digestion of food waste and waste activated sludge.The results showed that the co-fermentation of FW and WAS under appropriate process parameters,was conducted to generate rich enzyme activity.In the process,the optimal amylase was produced at 37 ?,pH 7 and the mass ratio of FW/WAS 2:1.The optimal protease was producted at 50 ?,pH 8 and the mass ratio of FW/WAS 2:1.The biggest amylase and protease activity are 10.02 U/mL and 19.25 U/mL,respectively.The enzyme products exhibited positive effects on the solubilization of WAS when added into the anaerobic digestion system.In addition,the next-generation DNA sequencing techniques(Ilumina sequencing)demonstr ated that the microbial community in enzyme-forming process grew quickly and the second growth showed smooth tendency with the addition of enzyme products into WAS.The predominant strains for secreting amylase were Lactobacillus and Clostridium-sensu-strito-1,and Aeromonas were the strains for secreting protease.