Biosynthesis of -DOPA by Aspergillus oryzae

The present investigation deals with the biosynthesis of -DOPA by parental (GCB-6) and mutant (UV-7) strains of Aspergillus oryzae. There was a marked difference between the mycelial morphology and pellet type of parental and UV-irradiated mutant culture. The mutant strain of A. oryzae UV-6 exhibited pellet-like mycelial morphology and improved tyrosinase activity. Mould mycelium was used for biochemical conversion of -tyrosine to -DOPA because tyrosinase is an intracellular enzyme. The mutant was found to yield 3.72 fold higher production of -DOPA than the parental strain. The mutant strain is stable and -glc-resistant. The comparison of kinetic parameters was also done which showed the greater ability of the mutant to yield -DOPA (i.e., Yp/x 40.00±0.01d mg/mg with parent and 182.86±0.02a mg/mg in case of mutant). When cultures grown for various incubation periods, were monitored for Qp, Qs and qp, there was significant enhancement (p<0.0025–0.005) in these variables by the mutant strain of A. oryzae UV-7 over GCB-6 on all the rates. -DOPA (3,4-dihydroxy phenyl -alanine) is a drug of choice in the treatment of Parkinsonʹs disease and myocardium following neurogenic injury.