Production of l-DOPA by tyrosinase immobilized on modified polystyrene
- 191 Downloads
Mushroom tyrosinase was immobilized on modified polystyrene—polyaminostyrene (PSNH) and polymethylchloridestyrene (PSCL)—to produce l-DOPA from l-tyrosine. Glutaraldehyde was used as an activating agent for the PSNH to immobilize the tyrosinase and 10% (w/v) glutaraldehyde was optimal in conferring the highest specific activity (11.96 U/g) to the PSNH. Methylchloride on the PSCL was directly linked with the tyrosinase, and 1.5 mmol of Cl/g was optimal in attaining the specific activity of 17.0 U/g. The temperature and optimal acidity were, respectively, 60°C and pH 5.5 for the PSNH, and 70°C and pH 3.0 for the PSCL. In a 50-mL batch reactor working over 36 h, the l-DOPA production rate at 30°C was 1.44 mg/(L·h) for the PSNH and 2.33 mg/(L·h) for the PSCL. The production rate over 36 h was 3.86 mg/(L·h) for the PSNH at 60°C and 5.54 mg/(L·h) for the PSCL at 70°C. Both of the immobilized enzymes showed a remarkable stability with almost no change in activity after being stored wet. The operational stability study indicated a 22.4% reduction in l-DOPA production for the PSNH and an 8.63% reduction for the PSCL over seven runs (each run was for 144h at 30°C) when the immobilized enzymes were used under turnover conditions. The immobilized tyrosinase was more stable on the PSCL than on the PSNH.
Index Entriesl-DOPA tyrosine tyrosinase enzyme immobilization modified polystyrene
Unable to display preview. Download preview PDF.
- 2.Foor, F., Morin, N., and Bostian K. A. (1993), Appl. Environ. Microbiol. 59, 3070–3075.Google Scholar
- 5.Freire, D. G., Carvalho, G. J., and Alves, T. M. (2000), Appl. Biochem. Biotechnol. 84–86, 791–800.Google Scholar
- 7.Sánchez-Ferrer, A., Rodríguez-López, J. N., García-Cánovas, F., and García-Carmona, F. (1995), Biochimica Biophysica Acta 1247, 1–11.Google Scholar
- 11.Wu, C. W., Lee, J. G., and Lee, W. C. (1998), Biotechnol. Appl. Biochem. 27, 225–230.Google Scholar
- 12.Duckworth, H. W. and Coleman, J. E. (1970), J. Biol. Chem. 245, 1613–1625.Google Scholar
- 13.Hartree, E. F. (1972), Anal. Chem. 48, 422–427.Google Scholar
- 17.García-Cánovas, F., Tudela, J., Martínez Madrid, C., Varón, R., García-Carmona, F., and Lozano, J. A. (1987), Biochimica Biophysica Acta 912, 417–423.Google Scholar
- 18.Miranda, M., Urbani, G., Di Vito, L., and Botti, D. (1979), Biochimica Biophysica Acta 585, 398–404.Google Scholar