BIOCONVERSION OF PENTOSE SUGARS TO ETHANOL BY FREE AND IMMOBILIZED CELLS OF CANDIDA-SHEHATAE (NCL-3501) - FERMENTATION BEHAVIOR

Fermentation of xylose and rice straw hydrolysate using free and immob ilized cells of Candida shehatae (NCL-3501) was studied in batch, fed- batch and continuous culture conditions. In general, ethanol yields (g ethanol/g sugar utilized) were higher with immobilized cells in all r eactor types. Fed-batch or continuous cultures exhibited higher ethano l yields and volumetric productivities. Candida shehatae (NCL-3501) ef ficiently utilized the sugars present in rice straw hemicellulose hydr olysate, prepared by two different methods, within 48 h. In continuous culture, using acid hydrolysate of rice straw, a steady-stare could b e maintained for 216 h with a volumetric ethanol productivity of 0.33 g/litre.