Fermentation of xylose and rice straw hydrolysate to ethanol by Candida shehatae NCL-3501.
Candida shehatae NCL-3501 utilized glucose and xylose efficiently in batch cultures. The specific rate of ethanol production was higher with mixtures of glucose and xylose (0.64-0.83 g g-1 cells d-1) compared to that with individual sugars (0.38-0.58 g g-1 cells d-1). Although the optimum temperature for growth was 30 degrees C, this strain grew and produced appreciable levels of ethanol at 45 degrees C. A stable ethanol yield (0.40-0.43 g g-1 substrate utilized) was obtained between 10 g L-1 and 80 g L-1 of initial xylose concentration. Conversion efficiency was further improved by immobilization of the cells in calcium alginate beads. Free or immobilized cells of C. shehatae NCL-3501 efficiently utilized sugars present in rice straw hemicellulose hydrolysate, prepared by two different methods, with 48 h. Ethanol yields of 0.45 g g-1 and 0.5 g g-1 from autohydrolysate, and 0.37 g g-1 from acid hydrolysate were produced by free and immobilized cells, respectively.
Abbi
M
M
Department of Microbiology, University of Delhi, India.
Kuhad
R C
RC
Singh
A
A
D002175:Candida / Q000378:metabolism*; D018914:Cells, Immobilized; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005690:Galactose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D012275:Oryza / Q000378:metabolism*; D013696:Temperature; D014994:Xylose / Q000378:metabolism*
D000431:Ethanol; D014994:Xylose; D005947:Glucose; D005690:Galactose