Increase in Production of Ethyl Alcohol by Yeast Treated with Ultra Violet Energy

Abstract

Observations regarding the effect of ultra violet light upon the fermenting power of yeast have been made by various authors. Owen and Morley 1 report an increase in activity of yeast after administration of appropriate dosages, while Tanner and Byerly 2 demonstrated an adverse effect. The first noted authors seem convinced that irradiation of the medium by means of ultra violet energy before introduction of yeast results later in enhanced growth of the microorganism, but Tanner and Byerly were unable to confirm this finding.

The object of our series of experiments was to determine whether exposure of yeast to ultra violet light is attended by subsequent increase in formation of ethyl alcohol.

For our purposes, we have utilized equipment set up as follows: The source of ultra violet was a quartz tube of approximately 24 inches length and one centimeter external diameter, of the type known ordinarily as “Cold Quartz” which operates with emission of very little heat and with much energy in the region of 2500-2800 A°. Placed outside of this quartz electrode, was an ordinary glass tube. Materials to be treated with the ultra light thus could pass between the outer wall of the quartz tube and the inner surface of that made of glass. The system was set up in a vertical position and fluids to be treated entered at the bottom and were withdrawn at the top. A variety of glass tubes of different diameters enclosing the inner quartz electrode permitted alteration of the thickness of layer of the fluid to be treated. Proper mixing during the period of treatment was brought about by intermittent surges of air introduced likewise at the lower end of the vertically placed apparatus.