Figure 3. Optimization of reaction conditions for whole-cell biotransformation and time course of the production of isomaltulose from sucrose in 5 L fermenter (A) Effect of temperature. (B) Effect of pH. (C) Effect of cell usages. (D) One-batch whole-cell biotransformation. (E) Recyclable synthesis of isomaltulose using a Corynebacterium glutamicum whole-cell biocatalyst. (), residual sucrose (), glucose production () and fructose production ().
Figure 4. Structure analysis of WT and mutants. (A) V280 was located in ɑ-helix, which could possibly form two new VDWs with Q329 and W330 in mutant L280 (B) Reddish dashed lines refer to VDWs; (C) Multiple sequence alignment of SIases from different species. Abbreviations are as follows: Erwinia rhapontici NCPPB 1578, ERSI; Pantoea dispersa UQ68J, PDSI; Serratia plymuthicaPAMC26656, SPSI; Enterobacter sp. FMB-1, ESI; Raoultella planticola UQ14S, RPSI; Pseudomonas mesoacidophila MX-45, MutB; Rhizobium sp. MX-45 (M1E1F7), RSI; Pectobacterium carotovorum , PCSI; (E) a new hydrophobic network including F499 and other residues (P24, W339, P495, and L519) was formed in S499(D), the hydrophobic interactions are shown as blue dashed line, π-cation stacked interaction between Trp339 and Phe499 is shown as magentas line; (F) Overall molecular interactions of V280L/S499F;
Figure 5. Molecular dynamics simulations. (A) The RMSD values of all backbone atoms for WT and mutants. (B) The RMSF values of each amino acid residue for WT and mutants. Letter I, II represent the amino acid position at site 280, 499, respectively.