Evaluation of Pretreatment Effect for Spent Mushroom Substrate on Methane Production

In this study, various pretreatments were applied to spent mushroom substrate (SMS) for the methane gas production by anaerobic digestion. Hydrothermal treatment, acid treatment using H2SO4, and alkali treatment using NaOH or KOH were applied and evaluated as pretreatment of SMS before anaerobic digestion. The methane gas produced was 119.1 mL/g-dry weight (D.W.) with untreated SMS, 55.5 mL/g-D.W. with hydrothermal treated SMS, 22.5 mL /g-D.W. with acid treated SMS, and 219.1 mL/g-D.W. with alkali treated SMS. These results demonstrated that the alkali treatment showed the largest amount of methane gas production between these pretreatments of SMS. Alkali treatment combined with heating did not show significantly affect the amount of methane gas production. Also, there was no significant difference in the amount of methane gas production between NaOH treatment and KOH treatment. These results indicated that optimum pretreatment for the methane gas production of SMS is alkaline treatment. It was also suggested that the no necessary for heat pretreatment of SMS and alkaline treatment such as KOH is most effective method of SMS pretreatment for the methane gas production by anaerobic digestion.