Ethanol production from high cellulose concentration by the basidiomycete fungus Flammulina velutipes

• Published in: Fungal biology 2013-03, Vol.117 (3), p.220-226
• Main Authors: Maehara, Tomoko, Ichinose, Hitomi, Furukawa, Takanori, Ogasawara, Wataru, Takabatake, Koji, Kaneko, Satoshi
• Format: Article
• Language: English
• Subjects: Basidiomycetes; beta-glucosidase; bioethanol; biomass; bioprocessing; carbon; cellobiose; Cellulase - chemistry; Cellulase - metabolism; Cellulolytic enzyme activity; cellulose; Cellulose - chemistry; Cellulose - metabolism; Consolidated bioprocessing; endo-1,4-beta-glucanase; ethanol; Ethanol - metabolism; Ethanol fermentation; ethanol production; Fermentation; Flammulina - metabolism; Flammulina velutipes; fructose; fungi; High substrate concentration; Hydrolysis; Industrial Microbiology; maltose; sucrose; sugarcane bagasse; Wood-rooting fungus
• ISSN: 1878-6146; 1878-6162
• DOI: 10.1016/j.funbio.2013.02.002

Ethanol production by Flammulina velutipes from high substrate concentrations was evaluated. F. velutipes produces approximately 40–60 g l−1 ethanol from 15 % (w/v) d-glucose, d-fructose, d-mannose, sucrose, maltose, and cellobiose, with the highest conversion rate of 83 % observed using cellobiose as a carbon source. We also attempted to assess direct ethanol fermentation from sugarcane bagasse cellulose (SCBC) by F. velutipes. The hydrolysis rate of 15 % (w/v) SCBC with commercial cellulase was approximately 20 %. In contrast, F. velutipes was able to produce a significant amount of ethanol from 15 % SCBC with the production of β-glucosidase, cellobohydrolase, and cellulase, although the addition of a small amount of commercial cellulase to the culture was required for the conversion. When 9 mg g−1 biomass of commercial cellulase was added to cultures, 0.36 g of ethanol was produced from 1 g of cellulose, corresponding to an ethanol conversion rate of 69.6 %. These results indicate that F. velutipes would be useful for consolidated bioprocessing of lignocellulosic biomass to bioethanol. ► Flammulina velutipes has the ability to produce ethanol from high-concentration sugars. ► 15 % w/v cellulose was hydrolyzed only 25 % using 9 mg g−1 cellulase. ► F. velutipes converted 15 % w/v cellulose to ethanol (69 %) adding 9 mg g−1 cellulase.