Ethanol production by immobilized Saccharomyces cerevisiae, Saccharomyces uvarum, and Zymomonas mobilis
Saccharomyces cerevisiae NRRL Y-2034, Saccharomyces uvarum NRRL Y-1347, and Zymomonas mobilis NRRL B-806 each were separately immobilized in a Ca-alginate matrix and incubated in the presence of a free-flowing and continuous 1,3,5, 10, or 20% (w/w) glucose solution. In general, the yeast cells converted 100% of the 1,3, and 5% glucose to alcohol within 48 h and maintained such a conversion rate for at least two weeks. The bacterium converted ca. 90% (w/w) of the 1,3, and 5% glucose to alcohol continuously for one week. However, both the yeast and bacterium were inhibited in the highest glucose (20% w/w) solution. All of the immobilized cultures produced some alcohol for at least 14 days. Immobilized Saccharomyces cerevisiae was the best alcohol producer of all of the glucose concentrations; the yeast yielded 4.7 g ethanol/100 g solution within 72 h in the 10% glucose solution. After 7-8 days in the 10% solution, Saccharomyces cerevisiae produced ethanol at 100% of theoretical yield (5.0 g ethanol/100g solution), with a gradual decrease in alcohol production by 14 days. Immobilized Saccharomyces uvarum produced a maximum of 4.0 g ethanol/100 g solution within 2 days and then declined to ca. 1.0 g ethanol/100g solution after 7 days continuous fermentation in the 10% glucose solution. Zymomonas mobilis reached its maximum ethanol production at 4 days (4.7 g/100 g solution), and then diminished similarly to Saccharomyces uvarum. The development of a multiple disk shaft eliminated the problem both of uneven distribution of alginate-encapsulated cells and of glucose channeling within the continuous-flow fermentor column. This invention improved alcohol production about threefold for the yeast cells. (Refs. 13).
- Research Organization:
- Northern Regional Research Center; Agricultural Research Science and Education Administration, US Dept of Agriculture, Peoria IL 61604
- OSTI ID:
- 7013119
- Journal Information:
- Biotechnol. Bioeng.; (United States), Vol. 24:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ETHANOL
BIOSYNTHESIS
SACCHAROMYCES CEREVISIAE
IMMOBILIZED CELLS
ZYMOMONAS MOBILIS
CHEMICAL REACTORS
COMPARATIVE EVALUATIONS
CULTURE MEDIA
FERMENTATION
GLUCOSE
YEASTS
ALCOHOLS
ALDEHYDES
BACTERIA
BIOCONVERSION
CARBOHYDRATES
FUNGI
HEXOSES
HYDROXY COMPOUNDS
MICROORGANISMS
MONOSACCHARIDES
ORGANIC COMPOUNDS
PLANTS
SACCHARIDES
SACCHAROMYCES
SYNTHESIS
090222* - Alcohol Fuels- Preparation from Wastes or Biomass- (1976-1989)
140504 - Solar Energy Conversion- Biomass Production & Conversion- (-1989)