Aureobasidium pullulaans를 이용한 Maltose로부터 Isomalto-oligosaccharides의 생산

Isomalto-oligosaccharide Production from Maltose by Intact Cells of Aureobasidium pullulaans

A Aureobasidium pullulans 균체를 이용하여 malt-ose로부터 isomalto-oligosaccharides를 생산하였다. 저농도의 maltose를 기질로 이용할 경우에는 가수분해활성이 transglucosylation활성보다 매우 강하여 isomalto-oligosaccharides 합성수율이 매우 낮았으나 400g/ P 이상의 고농도기질에서는 isomalto-oligosaccharides 합성이 유리하였다. isomaltomalto-oligosaccharides 생산의 반응 최적조건은 pH 4.5, 온도 $65^{\circ}C$, 균체농도는 기질 그램당 10unit이었다. 이때 생산된 isomaltooligosa-ccharides의 수율은 최고 48.35%였다. 반응초기에 maltose로부터 panose가 선택적으로 생산되었고, maltose가 더 이상 기질로 이용되지 못하는 반응시점에서 panose를 기질로 이용하여 isomaltotriose가 생산되었다.

A new method for the production of isomalto-oligosaccharides from maltose was investigated using intact cells of Aureobasidium pullulaans 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 $25^{\circ}C$. The optimum reaction conditions for the isomalto-oligosaccharide production were as follows: substrate concentration, 500g/l maltose; pH, 4.5; temperature, $65^{\circ}C$; 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 consumption was discontinued.