초록
The synthesis of fructo-oligosaccharides was carried out using whole cells of Microbacterium paraoxydans. Reactions were carried out using un-induced, inulin-induced and sucrose-induced cells displaying different amounts of invertase and inulinase activities out of which the best transfructosylation occurred using sucrose-induced cells displaying 12 I.U. invertase/0.75 I.U. inulinase activities. Using 40% w/v sucrose and in the sucrose-induced cells, a maximum fructo-oligosaccharide yield of 155g/l (corresponding to product yield of 0.38g/g initial substrate) was obtained. The major products synthesized were the tri-saccharide, 1-kestose [1<SUP>F</SUP> (1-β-d-fructofuranosyl)sucrose] and the tetrasaccharide, nystose [1<SUP>F</SUP> (1-β-d-fructofuranosyl)kestose]. A Box-Behnken design was used to optimize the factors affecting the fructo-oligosaccharide synthesis and these were at 31.5% sucrose, 10.96 I.U. invertase/0.69 I.U. inulinase and 14.32h incubation time leading to an overall yield of 0.44g/g initial substrate. The synthesized 1-kestose and nystose were purified to homogeneity by preparative TLC and structurally characterized by ESI-MS and 2D NMR.