Abstract
A duckweed, Wolffia arrhiza, was examined for its potential use as a feedstock for ethanol production. The starch contents of its turions, the plant’s dormant form, were 43%, whereas that of vegetative frond as the growth form was 13%. The ethanol yield from turions was 0.28 g－ethanol·g－biomass－1 in the simultaneous saccharification and fermentation mode (SSF) using a commercially available cellulase for enzymatic hydrolysis after alkaline / oxidative pretreatment. Ethanol was produced efficiently from starch-rich turions of W. arrhiza, in SSF using the amylase mixture with a comparable yield of 0.25 g－ethanol·g－biomass－1. Ethanol was produced from the vegetative fronds at the yield of 0.16 g－ethanol·g－biomass－1 in the SSF mode using cellulase, although that with the amylase mixture was only 0.07 g－ethanol/g－biomass. These results suggest that W. arrhiza, especially its turions, presents considerably high potential for use as an ethanol production feedstock.
