Santad Wichienchot, Poonsuk Prasertsan, Tipparat Hongpattarakere, and Robert A. Rastall

pp. 597 - 603

Abstract

This study investigated the optimal environmental factors for gluco-oligosaccharide production by Gluconobacter oxydans NCIMB 4943 from a range of commercial maltodextrins, and the influence of reaction parameters on the molecular weight distribution and chemical structure of the gluco-oligosaccharide products. G. oxydans gave significantly (p<0.01)
higher gluco-oligosaccharide yield in maltodextrin complex medium (30.4%) than using cell suspensions (19.6%). Cell concentration had a significant (p<0.05) effect on gluco-oligosaccharide yields at 24 h. The optimal pH was found to be 4.5 for the cell suspension method. Temperature had a significant (p<0.05) effect and the optimal temperature was found to be 30°C. Maximum yield (30.0%) was obtained with high dextrose equivalent (DE) maltodextrin in maltodextrin complex medium. Low DE substrates gave the lowest gluco-oligosaccharide yields. Substrate concentration affected gluco-oligosaccharide formation significantly (p<0.05). Low molecular weight (approximately 1 kDa) maltodextrin was converted to higher molecular weight gluco-oligosaccharide (7.8-65.6 kDa) with ratios of α-1,6-, α-1,4- and α-1,4,6-D-glucosidic linkages in the ranges of 1.37-3.99, 1.48-4.30 and 0.29-0.73 respectively, depending on the manufacturing conditions. Glucooligosaccharides contained at least 88 glucose residues.