Pullulan production by color variant strains of Aureobasidium pullulans

Abstract

Naturally occurring 'color variant' strains of Aureobasidium pullulans are distinguished from typical strains by their brilliant pigmentation, overproduction of secreted enzymes (xylanase), and low DNA relatedness. Color variants have not previously been examined for pullulan secretion. Among five independently isolated color variants, strains NRRL Y-12,974 and YB-4026 made the greatest amounts of pullulan from cornstarch, with conversion efficiencies of about 10%. Neither color variant nor typical strains made significant amounts of pullulan from the unconventional lactose or xylan substrates. Pullulan yields were inversely correlated with biomass production. Pullulan production thus appears to be a variable characteristic of both color variant and typically pigmented strains of A. pullulans, regulated by specific inducers during growth limitation. © 1988 Society for Industrial Microbiology.