A NEW VARIETY OF AUREOBASIDIUM-PULLULANS CHARACTERIZED BY EXOPOLYSACCHARIDE STRUCTURE, NUTRITIONAL PHYSIOLOGY AND MOLECULAR-FEATURES

The black yeast Aureobasidium pullulans (de Bary) Arnaud is known to s ynthesize the exopolysaccharide pullulan a poly-alpha-1,6-maltotriose. Nine strains were found to produce additional aubasidan-like EPS, i.e . glucans with alpha-1,4-D-, beta-1,6-D- and beta-1,3-D-glycosidic bon ds. These strains had previously been found to deviate in genotypic ch aracters. Additional physiological differences were found: the optimal nitrogen source for exopolysaccharide production in liquid medium was NaNO3 for aubasidan-producing strains, and (NH4)(2)SO4 for the remain ing strains. A new variety, A. pullulans var. aubasidani Yurlova, is d escribed for the strains producing aubasidan-like components. The new variety can be distinguished from A. pullulans var. pullulans by the a bsence of assimilation of methyl-alpha-D-glucoside and lactose.