Enhanced synthesis of l-threo-3,4-dihydroxyphenylserine by high-density whole-cell biocatalyst of recombinant l-threonine aldolase from Streptomyces avelmitilis
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- Baik, SH. & Yoshioka, H. Biotechnol Lett (2009) 31: 443. doi:10.1007/s10529-008-9885-0
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l-threo-3,4-Dihydroxyphenylserine (DOPS) is a chiral unnatural β-hydroxy amino acid used for the treatment of Parkinson disease. We developed a continuous bioconversion system for DOPS production that uses whole-cell biocatalyst of recombinant Escherichia coli expressing l-threonine aldolase (l-TA) genes cloned from Streptomyces avelmitilis MA-4680. Maximum conversion rates were observed at 2 M glycine, 145 mM 3,4-dihydroxybenzaldehyde, 0.75% Triton-X, 5 g E. coli cells/l, pH 6.5 and 10°C. In the optimized condition, overall productivity was 8 g/l, which represents 40 times the synthesis yield possible with no optimization of conditions.