Transformation of L-tyrosine to L-dopa by a novel fungus, Acremonium rutilum, under submerged fermentation.
ABSTRACT The present study deals with the transformation of L-tyrosine to L-dopa by Acremonium rutilum, a fungal tyrosinase producer, isolated from decomposed banana stud. This appears to be the first report on A. rutilum as a polyphenoloxidase producer with both cresolase and catecholase activity. Enriched Czapek-Dox agar was used for plate assay screening. Enriched potato dextrose broth was used for optimization studies, which induced high levels of L-dopa under submerged fermentation. A. rutilum gave the maximum L-dopa production (0.89 mg/ml) and tyrosinase activity (1095 U/mg) under the optimized parameters, that is, a temperature of 25 degrees C, pH 5.5, an inoculum size of 2.5 ml, and an incubation time of 72-120 h, with L-tyrosine (5 mg/ml) as substrate. Five resolved bands, with R(f) values of 0.73, 0.60, 0.54, 0.37, and 0.26, were observed, which confirmed the presence of L-dopa. This study involves the elevated profile of L-dopa production. Such study is needed, as L-dopa has the ability to control Parkinson's disease.
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ABSTRACT: Process Biochemistry j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / p r o c b i o a b s t r a c t The aromatic amino acid l-tyrosine is a compound with multiple applications in the food, pharmaceutical, cosmetic and chemical industries. This review summarizes the current knowledge on the metabolic pathways involved in the synthesis of this amino acid and the strategies employed to develop and improve microbial production strains. Common strategies for l-tyrosine overproduction include the elimination of negative feedback control in key pathway enzymes and increasing the pool of the aromatic precursors phosphoenolpyruvate and erythrose-4-phosphate. Following these approaches, production strains have been generated that allow the synthesis of l-tyrosine with a yield from glucose corresponding to 80% of the theoretical maximum. Recent developments in the utilization of l-tyrosine as a substrate for microbial and enzymatic conversion into valuable products are also presented and discussed. For example, the production of the aromatic polymer melanin has been reported by the bioconversion of l-tyrosine using an Escherichia coli strain expressing a gene encoding the enzyme tyrosinase from Rhizobium etli. Metabolic engineering by expressing genes encoding the enzyme p-hydroxyphenylacetate 3-hydroxylase in an E. coli strain modified for l-tyrosine production from glucose results in the capacity to synthesize l-3,4-dihydroxyphenylalanine, a compound employed for treating Parkinson's disease.Process Biochemistry 01/2012; 47(47):1017-1026. · 2.44 Impact Factor
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ABSTRACT: Penicillium jensenii (identified by Dept. of Mycology, Agharkar Research Institute, Pune) isolated from soil (rhizosphere zone) was found to be a potent tyrosinase producer. Tyrosinase is capable of bringing about biotransformation of a single amino acid tyrosine to L-DOPA (3, 4- dihydroxyphenylalanine) which is used as therapeutic agent in the treatment for Parkinson’s disease. Maximum yield of tyrosinase was 13 U/ml at 30oC in tyrosine broth (3mg/ml of tyrosine), pH 7 with an inoculum size of 5% w/v after 24 hrs of incubation under shake-culture conditions (120 rpm).International Journal of Scientific and Research Publications. 05/2012; 2(5):1-8.