Evaluation of Ethanol Fermentation Ability of Flammulina velutipes NBRC33210 from Starch by Consolidated Bioprocessing

Abstract

Ethanol fermentation from starch by a mushroom, Flammulina velutipes NBRC33210, was investigated. When the mycelia were anaerobically incubated with 5% of starch, only a small amount of ethanol was produced (less than 6% of the theoretical ethanol recovery rate). Aerobic culture was effective to produce amylolytic enzymes from F. velutipes and a significant amount of ethanol was produced (32.4% of the theoretical ethanol recovery rate) when the mycelia were anaerobically incubated with 5% of starch after 7 days of aerobic seed culture. Addition of α-amylase into the culture did not influence ethanol fermentation from starch, however, α-glucosidase and glucoamylase were effective for the ethanol fermentation by F. velutipes NBRC33210. The maximum ethanol conversion rate for the starch was 72.6 % when 0.1 U/mL of glucoamylase was added to the culture.