Identification of an ε‐Keto Ester Reductase for the Efficient Synthesis of an (R)‐α‐Lipoic Acid Precursor

Abstract

An ovelr eductase (CpAR2) with unusually high activity toward an e-keto ester, ethyl8 -chloro-6-oxooctanoate,w as isolated from Candida parapsilosis.T he asymmetric reductiono fe thyl8 -chloro-6-oxooctanoate using Escherichia coli cells coexpressing CpAR2 and glucose dehydrogenase genes gave ethyl (R)-8-chloro-6-hydroxyoctanoate, ak ey precursor for the synthesis of (R)-a-lipoic acid, in high space-time yield (530 gL À1 d À1)a nd with excellent enantiomeric excess( > 99%). This bioprocessw as shown to be viable on a1 0-L scale. This method provides ag reener andm ore cost-effective method for the industrial production of (R)-a-lipoic acid.

Coevolution of the Activity and Thermostability of an ϵ‐Keto Ester Reductase for Better Synthesis of an (R)‐α‐Lipoic Acid Precursor

“…Subsequently, a simple reaction optimization was carried out. When 5 % ( v / v ) DMSO instead of 5 % ( v / v ) EtOH was used as cosolvent and the reaction temperature was reduced to 35 °C from 40 °C, the same amount of substrate was completely converted within 4 h, providing a higher STY of 566 g L −1 d −1 , productivity similar to that achieved in our previous work but with a fivefold decrease in catalyst dosage. These results indicated that a more efficient engineered ϵ ‐keto ester reductase for the synthesis of the ( R )‐α‐lipoic acid precursor was developed by cooperative directed evolution.…”

“…The specific activity of variant S131Y/Q252I was increased to 214 U mg −1 from 120 U mg −1 . Moreover, the half‐deactivating temperature ( ) was 2.3 °C higher than that of the wild‐type enzyme, whereas the half‐life of the enzyme at 40 °C was increased to more than 24 h from 4.3 h. To simplify the preparation of biocatalysts, we coexpressed Cp AR2 S131Y/Q252I or Cp AR2 WT together with a glucose dehydrogenase ( Bm GDH) for NADPH regeneration in an E. coli cell according to previous reports . Whole cells of E. coli Cp AR2 WT / Bm GDH, Cp AR2 S131Y / Bm GDH, and Cp AR2 S131Y/Q252I / Bm GDH were then used as biocatalysts to perform the asymmetric reduction of ECOO.…”

Characterization of a Carbonyl Reductase from Rhodococcus erythropolis WZ010 and Its Variant Y54F for Asymmetric Synthesis of (S)-N-Boc-3-Hydroxypiperidine

“…In the chemical synthesis of ( S )-NBHP, employed strategies include the synthesis of racemic 3-hydroxypiperidine followed by chiral resolution and the enantiospecific synthesis of ( S )-NBHP from chiral precursors. The former only achieves a maximum yield of 50%, making the process economically unviable, while the latter appears to be limited because of the lengthy procedure, rather poor yields of the products, and the use of potentially hazardous reagents [1,5,6]. Alternatively, the carbonyl-reductase-catalyzed asymmetric reduction of N -Boc-3-piperidone (NBPO) has gained increasing focus due to its mild reaction conditions, high yield, and remarkable enantioselectivity [4,7,8,9].…”

Preparation of Chitosan Molecularly Imprinted Polymers and the Recognition Mechanism for Adsorption of Alpha-Lipoic Acid

“…In recent decades, mounting data have corroborated a broad spectrum of the potential health benefits of ALA including protection against cardiovascular disease [1], anti-inflammation [2], treatment for Alzheimer's disease and related dementias [3] and the inhibition of tumorigenesis [4]. These positive protective and curative effects have fostered significant motives in the chemical and enzymatical synthesis of ALA [5][6][7][8][9][10][11][12][13][14][15]. However, the synthesis is generally involved with expensive starting materials, complicated steps and low overall product yields [16].…”