Evaluation of waste mushroom medium from cultivation of shiitake mushroom (Lentinula edodes) as feedstock of enzymic saccharification

Abstract

The feasibility of using waste mushroom medium (WMM) as a substrate for enzymic saccharification to produce bioethanol or other bioproducts was investigated. WMM was broken up or left unbroken and stored at constant temperatures (5°, 15°, and 25°C) for 1 or 2 month(s) to accelerate lignin degradation by shiitake, which is a white rot fungus, and to increase the saccharification ratio. When the physicochemical properties of WMM and stored WMM were investigated, it was evident that the mushroom medium (MM) lignocellulose had decomposed during shiitake cultivation and its subsequent storage at a constant temperature. WMM and stored WMM were more susceptible to attack by cellulase than MM. When the unbroken WMM that was stored at 25°C for 2 months was saccharized with meicelase at 5 FPU/g substrate, its saccharification ratio was higher than that of unstored WMM. The maximum glucose yield of the stored WMM was 200.5 mg/g substrate, approximately 4.1 times as large as the value for autoclaved MM under the same saccharification condition. The saccharification ratio of the constituent cellulose was approximately 60%.