Evaluation of spent mushroom compost as a lignocellulosic substrate for hydrogen production by Clostridium thermocellum

Spent mushroom compost (SMC), waste cultivation medium of mushroom, is a potential lignocellulosic substrate. The characteristics of Clostridium thermocellum growing on SMC were investigated to provide practical guidance for better utilizing the SMC. SMC could be utilized without any pretreatment by C. thermocellum, and grinding, washing and mild chemical pretreatment could improve the fermentation performance of SMC, and consequently improved the hydrogen production. Grinding, washing and NaOH pretreatment increased hydrogen production by 48.48%, 62.09% and 2.61 times, respectively. Compared with washing method, neutralizing the alkali pretreated SMC with waste acid had no significant effect on hydrogen production, while could save a lot of water. Besides, fermentation without sterilization and medium simplification were feasible for the fermentation of SMC. The present study shows that SMC is a feasible substrate for consolidated bioprocessing, but pretreatments are needed to degrade the SMC more effectively.