Ultrasonic combined with enzymatic pretreatment strengthens anaerobic digestion of food waste
CHEN Jia-xin1, YAN Yi-ming1, LIU Shi-man1, FENG Yi-zhuo1, FEI Qiang1,2, MA Ying-qun1,2
1. School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, China; 2. Shaanxi Key Laboratory of Energy Chemical Process Intensification, Xi'an Key Laboratory of C1Compound Bioconversion Technology, Xi'an Jiaotong University, Xi'an 710049, China
Abstract：Microbial-based compound enzyme was in-situ prepared using food waste as the sole substrate in this study, and the effect and mechanism of ultrasonic combined with enzymatic pretreatment on methane production of food waste was investigated systematically. Results showed that the combined pretreatment could enhance the methane production of food waste, which was higher than that of single ultrasonic or enzymatic pretreatment, while increased the enzyme dosage could further improve the methane production. The maximal methane yield could reach (369.86±14.06)mL/g VS, which was 57.21% higher than that of the unpretreated food waste. The mechanism dissection revealed that the combined pretreatment promoted the decomposition of biomacromolecules in food waste, which was transferred from solid to liquid phase, thereby improving the biodegradability of fermentation substrate. Meanwhile, it was found that the combined pretreatment changed the protein secondary structure and destroyed the surface morphology of the food waste, and the degradation sequence of the main components in food waste was protein → lipid → starch. Moreover, the combined pretreatment reshaped the microbial community during the anaerobic digestion process by altering the characteristics of food waste, and the enrichment of Methanosaeta, a kind of acetotrophic methanogen, further enhanced the methane production.
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