Presentation Title

Production of a Commercial Yeast Culture Collection by Growth on Brewer’s Malt

Presenter Information

Lieren Jean Milton-Wood

Location

House of Learning Library, 3rd floor

Start Date

18-3-2016 12:00 PM

End Date

18-3-2016 6:00 PM

Abstract

In beer brewing, the brewer’s yeast, Saccharomyces cerevisiae, is the biocatalyst center for fermentation, converting carbon sources, such as glucose provided by malted barley, to energy, biomass, and the desired by-product, ethanol. The goal of this project is to create a simple, dependable commercial process for the production of brewer’s yeast at a scale of 10L. Once completed, this procedure will be used by BA Brewmaster, a local ‘U-brew’, for the growth and maintenance of a continuous source of yeast. The parameters to be optimized (while considering the U-brew’s infrastructure) include: inoculum, density, incubation temperature and time, aeration rate, vessel design, nutrient supply, and yeast storage conditions. Shake flask experiments were conducted to determine the optimum concentration of malt extract for yielding the highest number of viable yeast cells at room temperature (~23˚C) for 3 days. Malt concentrations of 0.05g/L to 0.001g/L were assessed and compared to glucose-malt yeast extract and controls. Yeast viability was assessed using spread plate techniques on Wallerstein Nutrient Medium, incubated at 30˚C for 2 days. Cell counts ranged from 8.20x106 CFU/mL to 9.40x107 CFU/mL, with the highest yield observed being 9.40x107 CFU/mL at 0.002g/L of malt extract. This experiment will benefit BA Brewmaster by significantly reducing yeast inoculum costs and allowing a yeast library to be established from which different strains can be cultured as desired.

Department

Biological Sciences

Faculty Advisor

Jonathan Van Hamme

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Mar 18th, 12:00 PM Mar 18th, 6:00 PM

Production of a Commercial Yeast Culture Collection by Growth on Brewer’s Malt

House of Learning Library, 3rd floor

In beer brewing, the brewer’s yeast, Saccharomyces cerevisiae, is the biocatalyst center for fermentation, converting carbon sources, such as glucose provided by malted barley, to energy, biomass, and the desired by-product, ethanol. The goal of this project is to create a simple, dependable commercial process for the production of brewer’s yeast at a scale of 10L. Once completed, this procedure will be used by BA Brewmaster, a local ‘U-brew’, for the growth and maintenance of a continuous source of yeast. The parameters to be optimized (while considering the U-brew’s infrastructure) include: inoculum, density, incubation temperature and time, aeration rate, vessel design, nutrient supply, and yeast storage conditions. Shake flask experiments were conducted to determine the optimum concentration of malt extract for yielding the highest number of viable yeast cells at room temperature (~23˚C) for 3 days. Malt concentrations of 0.05g/L to 0.001g/L were assessed and compared to glucose-malt yeast extract and controls. Yeast viability was assessed using spread plate techniques on Wallerstein Nutrient Medium, incubated at 30˚C for 2 days. Cell counts ranged from 8.20x106 CFU/mL to 9.40x107 CFU/mL, with the highest yield observed being 9.40x107 CFU/mL at 0.002g/L of malt extract. This experiment will benefit BA Brewmaster by significantly reducing yeast inoculum costs and allowing a yeast library to be established from which different strains can be cultured as desired.