Highly efficient Michael-type addition of acetaldehyde to beta-nitrostyrenes by whole resting cells of Escherichia coli expressing 4-oxalocrotonate tautomerase
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2013
Authors
Narancić, TanjaKadivojević, Jelena
Jovanović, Predrag

Francuski, Đorđe
Bigović, Miljan
Maslak, Veselin

Savić, Vladimir

Vasiljević, Branka

O'Connor, Kevin
Nikodinović-Runić, Jasmina

Article (Published version)

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Show full item recordAbstract
A novel whole cell system based on recombinantly expressed 4-oxalocrotonate tautomerase (4-OT) was developed and shown to be an effective biocatalyst for the asymmetric Michael addition of acetaldehyde to beta-nitrostyrenes. Optimal ratio of substrates (2 mM beta-nitrostyrenes and 20 mM acetaldehyde) and biocatalyst of 5 g of cell dry weight of biocatalyst per liter was determined. Through further bioprocess improvement by sequential addition of substrate 10 mM nitrostyrene biotransformation was achieved within 150 min. Excellent enantioselectivity (>99% ee) and product yields of up to 60% were obtained with beta-nitrostyrene substrate. The biotransformation product, 4-nitro-3-phenyl-butanal, was isolated from aqueous media and further transformed into the corresponding amino alcohol. The biocatalyst exhibited lower reaction rates with p-Cl-, o-Cl- and p-F-beta-nitrostyrenes with product yields of 38%, 51%, 31% and ee values of 84%, 88% and 94% respectively. The importance of the termi...nal,proline of 4-UT was confirmed by two proline enriched variants and homology modeling.
Keywords:
Biocatalyst / Michael addition / Nitrostyrene / 4-Oxalocrotonate tautomerase / Whole cellSource:
Bioresource Technology, 2013, 142, 462-468Publisher:
- Elsevier Sci Ltd, Oxford
Projects:
- Microbial diversity study and characterization of beneficial environmental microorganisms (RS-173048)
DOI: 10.1016/j.biortech.2013.05.074
ISSN: 0960-8524
PubMed: 23759430