Abstract
L-dopa is an amino acid derivative used for the cure of Parkinson’s disease, a degenerative disoreder of nervous system. The present study is concerned with the propagation of C. utilis NRRL-Y-1084 for L-dopa production from L-tyrosine as a basal substrate. Yeast cells were cultivated under stationary culture for the biochemical transformation of L-tyrosine to L-dopa. As tyrosinase (Catechol oxidase, EC 1.10.3.1) is an intracellular enzyme, pre-grown yeast cells were used as an enzyme source in the reaction mixture. The effect of different cultivation conditions and nutritional requirements such as initial pH, time of incubation, carbon, nitrogen and phosphate sources on the propagation of C. utilis was investigated. Optimal production was observed when cells were cultivated at pH 5.0 for 72 h. with the addition of cellobiose at a level of 2.5%, peptone at 1.0% and KH2PO4 at 0.2%. A 16 h old inoculum was added at a level of 10% (v/v). During the course of study, the maximum L-dopa production of 1.624 mg/ml was accomplished in the reaction broth with a cumulative tyrosinase activity of 174 U/mg of yeast cells. L-tyrosine consumption was found to be 1.965 mg/ml. All the biochemical reactions were performed aerobically at 50ºC for 1 h on a hotplate with magnetic stirrers
