초록
For evaluating duckweed biomass as a bioresource, the specific growth rate and the chemical constituents of duckweed of four kinds were investigated. Spirodela polyrrhiza, Lemna minor, Wolffia arrhiza, and Wolffia globosa commonly showed high specific growth rates of 0.22-0.30 d<SUP>-1</SUP> with initial concentrations of nitrogen >3.0 kg m<SUP>-3</SUP> and phosphorus >5.0 kg m<SUP>-3</SUP>. All duckweeds had high sugar contents greater than 300 g kg<SUP>-1</SUP> of dry mass. Especially, vegetative fronds of W. globosa showed the highest sugar content of 410 g kg<SUP>-1</SUP> of dry mass. The duckweed biomass was pretreated easily by heating at 121 <SUP>o</SUP>C for saccharification using α-amylase and amyloglucosidase. The ethanol yield of W. globosa biomass in the simultaneous saccharification and fermentation (SSF) using the enzymes and dry yeast was 170 g kg<SUP>-1</SUP> of dry mass, whereas the succinate yield in the SSF using the enzymes and Actinobacillus succinogenes was 200 g kg<SUP>-1</SUP> of dry mass. The production rates of ethanol and succinate from the W. globosa biomass were estimated as 0.58 kg m<SUP>-2</SUP> y<SUP>-1</SUP> and 0.68 kg m<SUP>-2</SUP> y<SUP>-1</SUP>, respectively. The biomass of duckweed, with its high growth rate and high starch content, can be an excellent renewable feedstock for the production of ethanol and succinate as building block chemicals for the replacement of petrochemicals.