Conservation of Xylose Fermentability inPhlebiaSpecies and Direct Fermentation of Xylan by Selected Fungi

In efforts to lower the cost of total conversion of lignocellulosic materials, utilization of hemicellulose must be considered. White-rot fungusPhlebiasp. MG-60 can produce ethanol directly from cellulose and has fermentation ability for glucose, cellulose, and xylose. Therefore, white-rot fungi can be considered a good candidate for consolidated bioprocessing to give bioethanol from lignocellulosic biomass, although little information is available on the direct fermentation of xylan. In the present study, somePhlebiaspecies were selected as candidates because of their ability to ferment xylose to ethanol more efficiently thanPhlebiasp. MG-60. This process indicated that the basidiomycetes that can produce ethanol from xylose are closely related genetically within thePhlebiagenus. The selectedPhlebiaspecies showed higher ethanol productivity from corn core and beechwood xylans thanPhlebiasp. MG-60. The ethanol yields from corn core xylan in culture withPhlebia acerinaHHB11146,Phlebia ludovicianaHHB9640, andPhlebia subochraceaHHB8494 were 46.2%, 46.7%, and 39.7% of theoretical maximum, and those from beechwood xylan were 19.09%, 17.7%, and 21.4% of the theoretical maximum, respectively.