Production of ethanol from starch by free and immobilized Candida tropicalis in the presence of alpha-amylase.
Candida tropicalis is a potentially useful organism for the commercial production of ethanol as it is capable of fermenting starch at a low rate. To enhance this carbon source utilization and increase the rate of alcohol production, we pretreated corn soluble starch with alpha-amylase. Starch liquefaction was sufficient to drive the fermentation and to convert 96% substrate to ethanol. Indeed, in the presence of exogenous alpha-amylase, 9% (w/v) soluble starch was converted to 43.1g ethanol/l in 65 h with a productivity of 0.65 g/l h. Thus, bio-ethanol production using free and calcium alginate-immobilized C. tropicalis does not require the saccharification step. Furthermore, fed-batch fermentation by free C. tropicalis cells increased the final concentration to 56 g ethanol/l, reaching published values for Saccharomyces cerevisiae recombinant strains expressing both alpha-amylase and glucoamylase.
Jamai
Latifa
L
Biotechnology Units, SMBA University, P.O. Box 1796 Atlas, Fez, Morocco.
Ettayebi
Khalil
K
El Yamani
Jamal
J
Ettayebi
Mohamed
M
D041022:Candida tropicalis / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation / Q000502:physiology*; D013213:Starch / Q000378:metabolism*; D000516:alpha-Amylases / Q000378:metabolism*
D000431:Ethanol; D013213:Starch; D000516:alpha-Amylases