title: Optimization of high molecular weight pullulan production by Aureobasidium pullulans in batch fermentations.
abstract: Of five strains of Aureobasidium pullulans studied, NRRL Y-2311-1 yielded the highest titer (26.2 g/L) of pullulan and formed the lowest amount of melanin-like pigment. Sucrose was superior to glucose as the carbon and energy source on the basis of yield and titer of pullulan produced. Pullulan titer was higher (26.2 vs 5.1 g/L), biomass concentration was lower (6.9 vs 12.7 g/L), and DO was lower (0 vs 60% of saturation) when the fermenter was agitated by a marine propeller compared to Rushton impellers. Pullulan produced by strain NRRL Y-2311-1 ranged in weight-average molar mass (M(w)) from 486 KDa and number-average molar mass (M(n)) from 220 Da on day 1 of growth to 390 KDa and 690 Da on day 6; M(w) declined by about 35% from day 1 to day 3, the day of maximum pullulan titer. For the other strains, the ranges of molar mass on the day of maximum pullulan titer were 338-614 KDa (M(w)) and 100-6820 Da (M(n)).
authors.affiliation: Department of Chemical Engineering, University of Connecticut, Storrs, Connecticut 06269, USA.
authors.forename: Larry H
authors.initials: LH
authors.lastname: Gibson
authors.forename: Robert W
authors.initials: RW
authors.lastname: Coughlin
mesh_terms: D001203:Ascomycota / Q000378:metabolism*; D005285:Fermentation; D005936:Glucans / Q000096:biosynthesis* / Q000737:chemistry; D008970:Molecular Weight
chemical_list: D005936:Glucans; C009109:pullulan