Pullulan production by Aureobasidium pullulans growing on hydrolysed potato starch waste

Abstract Enzymic hydrolysis of potato starch waste yielded a substrate suitable for growth and exopolysaccharide production by Aureobasidium pullulans . Hydrolysates produced by α -amylase alone gave the lowest yields of exopolysaccharide with a low proportion of pullulan. Continued hydrolysis with pullulanase and amyloglucosidase gave higher yields with a better proportion of pullulan, but prolonged hydrolysis did not improve the yield further. The oligosaccharide composition of the hydrolysates was determined by capillary electrophoresis following reductive amination with ethyl p -aminobenzoate. Maltose-rich hydrolysates, generated with β -amylase and pullulanase, yielded over twice as much pullulan as the corresponding glucose-rich syrups generated with amyloglucosidase and pullulanase. It is concluded that the composition of the starch hydrolysate is important in determining pullulan yield.