Bio-chemical Synthesis of Melanin Precursor-5,6-Dihydroxyindole (DHI)

In this study, the biological oxidation step for the synthesis of dopachrome (DC) from L-3 4-dihydroxyphenylalanine (L-Dopa) catalyzed by Saccharomyces cerevisiae BY4741/pYX212-TYR and the chemical step for the reductive synthesis of 5, 6-dihydroxyindole (DUO from DC were coupled, realizing the bio-chemical synthesis of DUI. By optimizing the reaction conditions and the oxygen supply strategy of the biological oxidation step, the conversion rate of L-Dopa increased to 94.75%; by optimizing the reaction conditions and chemical additives of the chemical reduction step, the yield of DUI increased to 90.03%. Ultra high performance liquid chromatography tandem quadrupole time of flight mass spectroscopy (UPLC-Q-TOF-MS) identification for the products showed that ofigomers existed in the reaction system.