2.2 Plasmids, strains and medium
All strains and plasmids used in this study as shown in Table S1.The sequence of SI gene from the Pantoea dispersa UQ68J (Pdsi ) (GenBank accession number: AY223549) without signal peptide was synthesized and sequenced by Suzhou GENEWIZ Company, and 6xHistag was added to the C-terminal of Pdsi for the protein purification. The Pdsigene was incorporated in between Hind III and EcoR I site of the E. coli/C. glutamicum shuttle plasmid pXMJ19 to generate pXMJ19-pdsi . E.coli strain JM109 was used as gene cloning host to construct recombinant plasmids. C. glutamium 13032 was used as expression host for the characterization of enzymatic properties and whole cells were used as biocatalysts for isomaltulose production.E. coli cells were cultured at 37℃ in LB medium (NaCl 10 g/L, peptone 10 g/L, yeast extract 5 g/L).C. glutamium 13032 cells were grown on BHI medium at 30℃. 25 μg/mL chloramphenicol was added when necessary.