A novel esterase, rPPE01, from Pseudomonas putida ECU1011 was heterologously expressed in Escherichia coli and identified for enzymatic resolution of hydroxy acids via O-deacetylation. α-Acetoxy carboxylates were converted with approximately 50% yield and excellent enantioselectivity (E>200) at a substrate concentration of 100 mM. The half-lives of rPPE01 were 14 days at 50°C and 30 days at 30°C, indicating the enzyme has relatively high thermostability. Another remarkable advantage of rPPE01 is that both the activity and thermostability were enhanced significantly in the presence of hydrophobic alkanes and ethers. rPPE01 retained 159% of its initial activity after incubation with 50% (v/v) n-heptane at 30°C for 60 days. The attractive organic-solvent tolerance, good thermostability and high enantioselectivity towards α-acetoxy carboxylates endow rPPE01 with the potential of practical application for the production of enantiopure hydroxy acids.
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