Effects of ultraviolet radiation on saccharomyces uvarum metabolism
The objective of this study was to measure the effect of UV radiation on the metabolism of Saccharomcyes uvarum in wort used in beer production. Pure yeast cultures were exposed to a Westinghouse G8T5 germicidal lamp for 10, 20, 30 and 40 minutes and added to fresh wort. The cultures were allowed to ferment for 96 hours at 130 C and fermentation products were assayed at 24 hour intervals and analyzed on a SCABA BEER ANALYZER. Metabolic parameters measured were balling, alcohol and cell count. Percent alcohol (V/V %) increased significantly at all exposures, but as the UV dosage increased, alcohol levels showed a significant decline with longer exposures. The assimilation of sugars or balling levels dropped at each exposure level among samples. The ability for the yeast to assimilate sugars decreased as UV exposure was increased although pitching rates fluctuated. (Pitching rates are the cell count readings at inoculation). None of the samples showed a logarithmic growth pattern, except for the controls which did not exhibit a lag phase. All other samples decreased cell counts as exposure levels increased, without peaks. Substrate availability was not a factor in the metabolism of Saccharomyces uvarum. Cell count levels at each exposure could have possibly affected the metabolic parameters because of excessive cell killing. Viabilities at the exposure levels studied show that the number of live cells available for nutrient uptake was lower at each level. However, the peak levels of the parameters measured were very close to the controls. Although the availability of cells was low, metabolic rates could have been altered by the UV light.
- Research Organization:
- Tennessee Technological Univ., Cookeville
- OSTI ID:
- 6151260
- Journal Information:
- J. Tenn. Acad. Sci.; (United States), Vol. 62:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NUTRIENTS
UPTAKE
SACCHAROMYCES
PHYSIOLOGY
ULTRAVIOLET RADIATION
BIOLOGICAL EFFECTS
METABOLISM
ELECTROMAGNETIC RADIATION
FUNGI
MICROORGANISMS
PLANTS
RADIATIONS
YEASTS
560130* - Radiation Effects on Microorganisms