Abstract
Although wheat mashes contain only growth-limiting amounts of free amino nitrogen, fermentations by active dry yeast (Saccharomyces cerevisiae) were completed (all fermentable sugars consumed) in 8 days at 20 degrees C even when the mash contained 35 g of dissolved solids per 100 ml. Supplementing wheat mashes with yeast extract, Casamino Acids, or a single amino acid such as glutamic acid stimulated growth of the yeast and reduced the fermentation time. With 0.9% yeast extract as the supplement, the fermentation time was reduced from 8 to 3 days, and a final ethanol yield of 17.1% (vol/vol) was achieved. Free amino nitrogen derived in situ through the hydrolysis of wheat proteins by a protease could substitute for the exogenous nitrogen source. Studies indicated, however, that exogenously added glycine (although readily taken up by the yeast) reduced the cell yield and prolonged the fermentation time. The results suggested that there are qualitative differences among amino acids with regard to their suitability to serve as nitrogen sources for the growth of yeast. The complete utilization of carbohydrates in wheat mashes containing very little free amino nitrogen presumably resulted because they had the "right" kind of amino acids.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Beck C., von Meyenburg H. K. Enzyme pattern and aerobic growth of Saccharomyces cerevisiae under various degrees of glucose limitation. J Bacteriol. 1968 Aug;96(2):479–486. doi: 10.1128/jb.96.2.479-486.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Casey G. P., Ingledew W. M. Ethanol tolerance in yeasts. Crit Rev Microbiol. 1986;13(3):219–280. doi: 10.3109/10408418609108739. [DOI] [PubMed] [Google Scholar]
- Casey G. P., Magnus C. A., Ingledew W. M. High-gravity brewing: effects of nutrition on yeast composition, fermentative ability, and alcohol production. Appl Environ Microbiol. 1984 Sep;48(3):639–646. doi: 10.1128/aem.48.3.639-646.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cooper T. G., Britton C., Brand L., Sumrada R. Addition of basic amino acids prevents G-1 arrest of nitrogen-starved cultures of Saccharomyces cerevisiae. J Bacteriol. 1979 Mar;137(3):1447–1448. doi: 10.1128/jb.137.3.1447-1448.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- González E. Two-carbon assimilative capacity and the induction of isocitrate lyase in Saccharomyces cerevisiae. J Bacteriol. 1977 Mar;129(3):1343–1348. doi: 10.1128/jb.129.3.1343-1348.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nagodawithana T. W., Steinkraus K. H. Influence of the rate of ethanol production and accumulation on the viability of Saccharomyces cerevisiae in "rapid fermentation". Appl Environ Microbiol. 1976 Feb;31(2):158–162. doi: 10.1128/aem.31.2.158-162.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sumrada R., Cooper T. G. Basic amino acid inhibition of cell division and macromolecular synthesis in Saccharomyces cerevisiae. J Gen Microbiol. 1978 Sep;108(1):45–56. doi: 10.1099/00221287-108-1-45. [DOI] [PubMed] [Google Scholar]
- Viegas C. A., Sá-Correia I., Novais J. M. Nutrient-Enhanced Production of Remarkably High Concentrations of Ethanol by Saccharomyces bayanus through Soy Flour Supplementation. Appl Environ Microbiol. 1985 Nov;50(5):1333–1335. doi: 10.1128/aem.50.5.1333-1335.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]