Enzymatic hydrolysis of the organic fraction of municipal solid waste for sugar recovery

By Hochschule Bremerhaven

This study focused on enzymatic hydrolysis (EH) of the complex and heterogeneous organic fraction of municipal solid waste (OFMSW) with the aim of sugar recovery. Various factors, including OFMSW composition and pretreatment techniques, were examined for their impact on EH. It was found that three-day anaerobic digestion results in the depolymerization of sugar fibers and accumulation of monomeric sugars, and the same result was observed for thermal pretreatment. The study examined different pretreatment combinations for breaking down the organic waste, such as anaerobic incubation and heat pretreatment combined with enzymatic hydrolysis or enzymatic hydrolysis alone. The results demonstrated that the most successful method involved combining enzymatic hydrolysis with thermal pretreatment at a temperature of 100℃ for a duration of 4 hours. Surprisingly, a saccharification yield of over 51% was achieved using just 1 FPU of Cellic® CTec3 (Novozymes A/S) and 0.5 U glucoamylase AMG® 300 L BrewQ (Novozymes A/S) per 100 g of OFMSW dry matter. Further increase of the enzymatic dosages by 30 times enhanced saccharification by 32%, reaching a final hydrolysis yield of 83%. Moreover, sugar-rich hydrolysates underwent ethanol fermentation using Saccharomyces cerevisiae, resulting in the successful conversion of glucose to ethanol with the highest yield of 33 g of ethanol per 100 g of OFMSW dry matter. However, ethanol fermentation faced limitations at high enzymatic dosages, potentially due to the gradual increase in the production of organic acids such as lactic, malic, and succinic acids, likely produced by contaminants, as the enzymatic dosage increased. Further research is required to optimize the saccharification process of OFMSW and enhance the efficiency of subsequent bioprocesses.

Stanislav Rudnyckyj, PhD Student from Aalborg University, disseminating FLEXI-GREEN FUELS results at the EUBCE Conference in Bologna.


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This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 101007130.