A novel transglycosylation reaction from sucrose to L-ascorbic acid by a recombinant sucrose phosphorylase from Bifidobacterium longum was used to produce a stable L-ascorbic acid derivative. The major product was detected by HPLC, and confirmed to be 2-O-alpha-D-glucopyranosyl-L-ascorbic acid by LC-MS/MS analysis.

A DNA fragment, which complemented the growth of E. coli both on M9 medium containing raffinose and on LB medium containing ampicillin, IPTG and 5-bromo-4-chloro-3-indoxyl-alpha-D-galactoside, was isolated from the genomic library of Bifidobacterium longum SJ32, which had been digested with EcoRI. In the cloned DNA fragment, a gene encoding a sucrose phosphorylase (splP) and a partially cloned putative sucrose regulator gene (splR) were identified using the deletion analysis and sequence analysis. A 56 kDa protein was synthesized in E. coli and partially purified by DEAE-ion exchange chromatography. The partially purified enzyme did not react with melibiose, melezitoze and raffinose but did with sucrose. It had transglucosylation activity in addition to hydrolytic activity.