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A new method for the production of isomalto-oligosaccharides from maltose was investigated using intact cells of Aureobasidium pullulans which had been known to produce fructo-oligosaccharides. The cells showed transglucosylation activity producing isomalto-oligosaccharides at high concentrations of maltose, while they showed a hydrolytic activity at low concentrations of substrate when cultivated at 25 C. The optimum reaction conditions for the isomalto-oligosaccharide production were as follows : substrate concentration. 500 g/l maltose ; pH, 4.5 ; temperature, 65C; cell dosage, 10 unit per gram substrate. Under optimized conditions, the maximum yield of isomalto-oligosaccharides achieved was around 48 % ( w w). At the early period of reaction, panose was selectively produced from maltose, and thereafter isomaltotriose was synthesized by utilizing panose as a substrate when maltose comsumption was discontinued.
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