Roadmap for the synthesis of 2,5-DMP using L-threonine as a substrate EcSstT–Threonine transporter derived from Escherichia coli; EcTDH–L-threonine dehydrogenase derived from Escherichia coli; EhNOX–NADH oxidase derived from Enterococcus hirae; ScAAO–Aminoacetone oxidase derived from Streptococcus cristatus; SR-spontaneous reaction