Production of ethanol by yeasts grown on hydrolysate of Egyptian sweet potato
Egyptian Journal of Food Science. 1993; 21 (2): 171-80
in English
| IMEMR
| ID: emr-119941
ABSTRACT
The influence of different concentrations of HCl for acid hydrolysis of Egyptian sweet potato for maximal ethanol yield was studied. The optimum HCl concentration was 0.5 N with respect to reducing sugars formed [60% DE] and minimum hydroxymethyl furfural content [0.05%] at 97C for 20 minutes. Total solids for Egyptian sweet potato was 27%, reducing sugars and glucose content based on fresh weight were 27.53%, 26.7%, respectively. Both hydrolyzed sweet potato slurry [SPS] and glucose [at concentration 4.5%] were subjected to fermentation by 4 different yeast strains for 4 days of growth. The results showed optimum ethanol yield after 72 hours of fermentation with respect to Saccharomyces cerevisiae, Saccharomyces uvarum yielding 0.3 g/g, 0.31 g/g, respectively. Upon using Pachysolen tannophilus, the maximum ethanol yield was obtained after the first 24 hours 0.24% g/g and Pichia pinus was 0.27 g/g after 48% hours of fermentation. The yields of yeast cells were estimated after 96 hours of fermentation and indicated the presence of high dry weight of cells [4.0-8.5 g/L] with considerable amounts of crude protein [35-45%] and true protein [20.3-27.4%]
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Index:
IMEMR (Eastern Mediterranean)
Main subject:
Saccharomyces cerevisiae
/
Vegetables
Language:
English
Journal:
Egypt. J. Food Sci.
Year:
1993
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