Novel strategy for enhancing productivity in L-DOPA synthesis: The electroenzymatic approach using well-dispersed L-tyrosine

Abstract

Although L-DOPA (L-3,4-dihydroxyphenylalanine) is widely used as a drug for Parkinson's disease, there are critical drawbacks in the commercial synthetic method such as low conversion rate, poor productivity, and long operational time. In order to overcome these limitations, a novel electroenzymatic system using tyrosinase/carbon nanopowder/polypyrrole composite as a working cathode was reported with the outstanding conversion rate up to 95.9%. However, the productivity was still limited due to a low solubility of the substrate L-tyrosine in aqueous phase. Herein, we demonstrated a novel strategy for enhancing the productivity by employing well-dispersed L-tyrosine as the substrate. When using well-dispersed L-tyrosine, not only the concentration of the substrate was increased to 90.6 gL(-1) in aqueous phase but also the productivity was enhanced up to 15.3 gL(-1) h(-1). We also determined kinetic parameters in the electroenzymatic system and the kinetic results revealed that the outstanding conversion rate was based on the fast electrical reduction of the by-product to L-DOPA. Thus the electroenzymatic synthesis using well-dispersed L-tyrosine can be a potential candidate as a novel process for L-DOPA synthesis. (C) 2013 Elsevier B.V. All rights reserved.