Inducive effect of L-methionine in transformation of L-tyrosine to L-Dopa and tyrosinase production by Streptomyces sp VRS9

Abstract

A total of 52 isolates of actinomycetes were isolated from dry land soils of Gulbarga region, Karnataka, India. The actinomycete designated as isolate VRS9 was selected for its high tyrosinase (monophenolase) activity (67 U/mL) in standard medium. The taxonomical properties of the isolate were examined according to the International Streptomyces Project (ISP) scheme and the isolate VRS9 was assigned to the Genus Streptomyces. The inducive effect of L-methionine on transformation of L-tyrosine to L-Dopa (3,4-dihydroxyphenyl-L-alanine) under submerged conditions using Streptomyces sp. VRS9 was investigated. The fermentation was carried at 35 degrees C and pH 8.0, which were optimum physical conditions applied to test the effect of methionine on tyrosinase and L-Dopa production. Studies showed 1.15 and 0.52 folds higher production of tyrosinase and L-Dopa, respectively as compared to bioreaction conducted without addition of methionine. VRS9 gave the maximum L-Dopa production (0.90 mg/mL) and tyrosinase activity (289 U/mL) at 10 mM concentration of methionine added during the beginning of log phase.