Optimization of Biotransformation of l-Tyrosine to l-DOPA by Yarrowia lipolytica-NCIM 3472 Using Response Surface Methodology

Abstract

l-DOPA (3,4-dihydroxyphenyl-l-alanine) is the most widely used drug for treatment of Parkinson's disease. In this study Yarrowia lipolytica-NCIM 3472 biomass was used for transformation of l-tyrosine to l-DOPA. The process parameters were optimized using response surface methodology (RSM). The optimum values of the tested variables for the production of l-DOPA were: pH 7.31, temperature 42.9 °C, 2.31 g l(-1) cell mass and 1.488 g l(-1)l-tyrosine. The highest yield obtained with these optimum parameters along with recycling of the cells was 4.091 g l(-1). This optimization of process parameters using RSM resulted in 4.609-fold increase in the l-DOPA production. The statistical analysis showed that the model was significant. Also coefficient of determination (R(2)) was 0.9758, indicating a good agreement between the experimental and predicted values of l-DOPA production. The highest tyrosinase activity observed was 7,028 U mg(-1) tyrosine. l-DOPA production was confirmed by HPTLC and HPLC analysis. Thus, RSM approach effectively enhanced the potential of Y. lipolytica-NCIM 3472 as an alternative source to produce l-DOPA.

Keywords: Box–Behnken design; RSM; Tyrosinase; Yarrowia lipolytica; l-DOPA; l-Tyrosine.

Fig. 1

Three-dimensional response surface curve showing the effect of interactions of a pH and temperature, b pH and cell mass, c pH and l-tyrosine, d temperature and cell mass, e temperature and l-tyrosine, and f cell mass and l-tyrosine