title: Pullulan Elaboration by Aureobasidium pullulans Protoplasts.
abstract: Protoplasts of Aureobasidium pullulans are capable of producing pullulan. Biosynthesis of the polymer pullulan required induction with kinetics similar to those of whole cells. The protoplasts also produced a heteropolysaccharide component containing mannose, glucose, and galactose. The relative proportions of the pullulan and heteropolysaccharide fractions were a function of glucose concentration, with the pullulan content of the total polysaccharide rising from 20% at 2.5 mM glucose to 45% at 20 mM glucose. Elaboration of pullulan by both cells and protoplasts was sensitive to 0.6 M KCl, which was present as the osmotic stabilizer in protoplast experiments. The presence of KCl resulted in a shift in the pH optimum to a more acidic value. The molecular weight of the protoplast-derived pullulan was sharply reduced from the molecular weight of the whole-cell-derived product. Exposure of the protoplasts to proteolytic enzymes had no effect on polysaccharide elaboration.
authors.affiliation: Department of Microbiology and Immunology, The University of Western Ontario, and The London Research Centre, Agriculture Canada, London Ontario, Canada N6A 5B7.
authors.forename: M A
authors.initials: MA
authors.lastname: Finkelman
authors.forename: A
authors.initials: A
authors.lastname: Vardanis