title: High performance microbiological transformation of L-tyrosine to L-dopa by Yarrowia lipolytica NRRL-143.
abstract: BACKGROUND
  The 3,4-dihydroxy phenyl L-alanine (L-dopa) is a drug of choice for Parkinson's disease, controlling changes in energy metabolism enzymes of the myocardium following neurogenic injury. Aspergillus oryzae is commonly used for L-dopa production; however, potential improvements in ease of handling, growth rate and environmental impact have led to an interest in exploiting alternative yeasts. The two important elements required for L-dopa production are intracellular tyrosinases (thus pre-grown yeast cells are required for the transformation of L-tyrosine to L-dopa) and L-ascorbate, which acts as a reducing agent.
  
  
  RESULTS
  Pre-grown cells of Yarrowia lipolytica NRRL-143 were used for the microbiological transformation of L-tyrosine to L-dopa. Different diatomite concentrations (0.5-3.0 mg/ml) were added to the acidic (pH 3.5) reaction mixture. Maximum L-dopa biosynthesis (2.96 mg/ml L-dopa from 2.68 mg/ml L-tyrosine) was obtained when 2.0 mg/ml diatomite was added 15 min after the start of the reaction. After optimizing reaction time (30 min), and yeast cell concentration (2.5 mg/ml), an overall 12.5 fold higher L-dopa production rate was observed when compared to the control. Significant enhancements in Yp/s, Qs and qs over the control were observed.
  
  
  CONCLUSIONS
  Diatomite (2.0 mg/ml) addition 15 min after reaction commencement improved microbiological transformation of L-tyrosine to L-dopa (3.48 mg/ml; p < or = 0.05) by Y. lipolytica NRRL-143. A 35% higher substrate conversion rate was achieved when compared to the control.
authors: Institute of Industrial Biotechnology (IIB), GC University Lahore, Katchehry Road, Lahore-54000, Pakistan. alisbiotech@yahoo.com
authors: Sikander
authors: S
authors: Ali
authors: Jeffry L
authors: JL
authors: Shultz
authors: Ikram-Ul-Haq
mesh_terms: D018533:Biomass; D001711:Biotransformation / Q000187:drug effects; D007692:Diatomaceous Earth / Q000494:pharmacology; D005656:Fungal Proteins / Q000378:metabolism; D007218:Industrial Microbiology / Q000379:methods; D007700:Kinetics; D007980:Levodopa / Q000378:metabolism*; D008954:Models, Biological; D014442:Monophenol Monooxygenase / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism*; D025062:Yarrowia / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D014443:Tyrosine; D007980:Levodopa; D007692:Diatomaceous Earth; C033787:diatomite; D014442:Monophenol Monooxygenase
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