Production of D-sorbitol and L-sorbose from jerusalem artichoke by Zymomonas mobilis and Gluconobacter suboxydans = Zymomonas mobilis와 Gluconobacter suboxydans를 이용한 돼지감자로부터 D-sorbitol 및 L-sorbose 생성에 관한 연구

Abstract

The use of Jerusalem artichoke containing 현-2-fructose oligomer for the production of D-sorbitol and L-sor)ose has been studied. The employment of inulinase(0.398%，v/v) for the hydrolysis of 40% (v/w) Jer isalem artichoke juice resulted in 36.7g/l of glucose and 85.3g/l of fructose at 50°C. These sugars wi re utilized as substrates for D-sorbitol and L-sorbose production. Coimmobilization of inulinase Lnd permeabilized cells of Zymomonas mobilis in the mixture of chitin(5%, w/v) and x~ carrageen .n(4%，w/v) resulted in the prduction of 30.2g/l of D-sorbitol by using inulin as a substrate. Th process of L-sorbose production from D-sorbitol by Gluconobacter suboxydans was optimized with respt:t to the substrate concentration, level of dissolved oxygen and gluconic acid concentration. Gluconic icid produced by Zymomonas mobilis from glucose was found to inhibit Gluconobacter suboxydam in conversion of D-sorbitol to L-sorbose. In view of removing such inhibitory effect by gluconic acic. mutants were selected by the NTG (N-methyl-N-N'-nitro-N-nitrosoguanidine) treated method. Witants selected by NTG mutagenesis showed no inhibitory effects of gluconic acid against L-sorbose pr)duction when its concentration increased up to 100g/l. A mutant produced 40.1g/^ of L-sorbose in the medium containing 100g/감 D-sorbitol and 100g/^ gluconic acid. This result is considerable when compared with L-sorbose concentration(21.7g/1) obtained from the fermentation with wild type straii of Gluconobacter suboxydans.