Fusion glycosyltransferase design for enhanced conversion of rebaudioside A into rebaudioside M in cascade

•Two glycosyltransferases were fused for cascade synthesis of Rebaudioside M.•The fusion produced by yeast with high yields were efficient at 42°C and pH 7.0.•Length of peptide linker in the fusion was optimized for substrate channeling.•The fusion significantly enhanced bioconversion than just mixed enzymes.•Whole-cell catalysts showed good efficiency, thermostability and recyclability.