Pullulan production by Aureobasidium pullulans growing on hydrolysed potato starch waste

Enzymic hydrolysis of potato starch waste yielded a substrate suitable for growth and exopolysaccharide production by Aureobasidium pullulans. Hydroly sates produced by alpha-amylase alone gave the lowest yields of exopolysacc haride with a low proportion of pullulan. Continued hydrolysis with pullula nase and amyloglucosidase gave higher yields with a better proportion of pu llulan, but prolonged hydrolysis did not improve the yield further. The oli gosaccharide composition of the hydrolysates was determined by capillary el ectrophoresis following reductive amination with ethyl p-aminobenzoate, Mal tose-rich hydrolysates, generated with beta-amylase and pullulanase, yielde d over twice as much pullulan as the corresponding glucose-rich syrups gene rated with amyloglucosidase and pullulanase. It is concluded that the compo sition of the starch hydrolysate is important in determining pullulan yield . (C) 1999 Elsevier Science Ltd. All rights reserved.