Co-digestive performance of food waste and hydrothermal pretreated corn cob

Anaerobic co-digestion of lignocellulosic biomass and food waste (FW) has been extensively applied. However, whether hydrothermal pretreatment (HTP) of lignocellulosic biomass can enhance the performance in co-digestion deserves further investigation. In this study, corn cob (CC) was adopted as a typical lignocellulosic biomass for co-digestion with FW at different VS ratios of 1:3 (S1-S4) and 1:6 (S5-S8), attempting to evaluate the effect of HIP of CC at different temperature gradients (125, 150 and 175 degrees C) on the co-digestion performance. The emphasis was placed on hydrolysis, acidification and methanogenesis for different feedstock conditions. Results illustrated that the HTP had a certain destroying effect on the lignocellulose structure in CC and the crystallinity of cellulose decreased, significantly facilitating its co-digestion with FW. For FW/CC co-digestion at the VS ratio of 1:3, the 53 group (CC was pretreated at 150 degrees C) reached the maximum cumulative biogas yield (CBY) of 4660 mL and the maximum specific methane yield (SMY) of 316.9 mL/g.VS. Moreover, at 1:6, S7 group (pretreated at 150 et) exhibited the optimal CBY of 4100 mL while achieving the SMY of 277.6 mL/g.VS among the digesters, indicating that the co-digestion of preheated CC and FW could achieve higher methane production, and 150 degrees C refers to the optimal pretreatment temperature. Moreover, the peak values of the accumulated VFAs in digesters S1-54 (2000-3000 mg/L) is higher than that in digesters 55-58 (800-1500 mg/L). As suggested from microbial community and diversity date, the HTP expedited the enrichment of system hydrolyzing and addogenic bacteria. These results are significant and provide certain guidance for optimizing the co-digestion of FW and CC in actual engineering. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the effect of hydrothermal pretreatment on corn cob in co-digestion with food waste, showing that the pretreatment significantly facilitates the co-digestion of the two materials. Different conditions of co-digestion yield varying results, with 150°C being the optimal pretreatment temperature. The research also suggests that hydrothermal pretreatment accelerates the enrichment of hydrolyzing and methanogenic bacteria in the system.