Construction and characterization of a novel glucose dehydrogenase-leucine dehydrogenase fusion enzyme for the biosynthesis of l-tert-leucine

Abstract Background Biosynthesis of l - tert -leucine ( -tle), a significant pharmaceutical intermediate, by cofactor regeneration system friendly and efficiently is worthful goal all the time. The leucine dehydrogenase (LeuDH) glucose (GDH) has showed great coupling catalytic efficiency in synthesis -tle, however multi-enzyme complex GDH LeuDH never been constructed successfully. Results In this work, novel fusion enzyme (GDH–R3–LeuDH) for efficient biosynthesis -tle was mediated with rigid peptide linker. Compared free enzymes, both environmental tolerance thermal stability GDH–R3–LeuDH had improved since structure. structure also accelerated rate maintained activity, so productivity yield enhanced twofold. Finally, space–time catalyzing whole cells could achieve 2136 g/L/day 200 mL scale under optimal catalysis conditions (pH 9.0, 30 ° C, 0.4 mM NAD + 500 substrate including trimethylpyruvic acid glucose). Conclusions It first report about as to synthesize reach highest up now. These results demonstrated potential -tle.