VIEW ARTICLE DOI: 10.1094/ASBCJ-35-0025
Two Verdant Types of Saccharomyces uvarum. E. J. Kot and J. Raymond Helbert, Miller Brewing Company, Milwaukee, WI 53201. J. Am. Soc. Brew. Chem. 35:0025, 1977.
Wallerstein Laboratories Nutrient (WLN) agar has been used for differentiating normal colonies of Saccharomyces uvarum from mutant colonies and for subdividing the latter into petites and verdants. In our hands, petites all formed small colonies with dark green centers and white edges. Verdants, however, formed colonies with very different shades of green. This study was undertaken to explore the differences among verdants. Cytochrome absorption spectra of verdant isolates grown aerobically in a low-glucose broth at 25°C revealed two cytochrome patterns. The moderately green verdant, L3G, possessed a normal cytochrome absorption spectrum, while the dark green verdant, 16-7, lacked cytochromes aa3, b, and c1. In addition, the dark green verdant accumulated a substance absorbing at 575 nm, possibly the cytochrome precursor, protoporphyrin IX. Oxygen uptake studies indicated that the moderate green verdant was respiratory-sufficient, while the dark green one was respiratory-deficient. Although the moderate green verdant did not differ from the normal control in respiration, a metabolic difference was found. The moderate green verdant used maltotriose more rapidly than the normal control. These results demonstrate at least two types of verdants which may be isolated on WLN agar. Both verdants produced inferior beer and are undesirable in pitching yeast.
Keywords: Cytochromes, Mutants, Protoporphyrin IX, Respiration.