We have examined physiological growth limits and enzymatic activity of four species of black yeasts from the genus Aureobasidium (A. pullulans, A. melanogenum, A. subglaciale, A. namibiae). We have determined the growth limits on a solid agar media with glucose at two different variables, temperature (0-42 °C) and salt concentration (0-20 %) and examined enzymatic activity on solid and liquid culture media containing complex carbon sources (xylan, starch, pectin, lignin, naphtalene, celulose, chitin, casein, tributyrin, tanic acid, Tween 80). After the determination of growth limits we have checked enzymatic activity on solid and in liquid media, also by using resazurin dye in liquid media. We have found that yeasts can grow at salt concentrations to up to 19 % NaCl (A. pullulans) and the temperatures between 0 °C (A. pullulans, A. subglaciale, A. namibiae) and 37 °C (A. melanogenum). The highest enzyme activity was detected in the culture media containing xylan, pectin, starch and casein. The growth of yeasts did not occur in media with chitin and naphthalene. At the end we confirmed existence of some of the selected enzymes by comparing protein sequences of studied species with protein sequences from selected reference strains. This study characterized the temperature growth limits and tolerance to NaCl as well as optimized the resazurin dye method for further researches on species from the genus Aureobasidium.
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