Enantioselective Enzymatic Hydrolysis of rac-Mandelonitrile to R-Mandelamide by Nitrile Hydratase Immobilized on Poly(vinyl alcohol)/Chitosan–Glutaraldehyde Support

Abstract

Nitriles, amides and carboxylic acids have varied applications in active pharmaceutical intermediate (API), drug and chemical industry, and particularly in the synthesis of pure enantiomers of chiral compounds. The chemical hydrolysis of nitrile compounds is well studied, but it necessitates harsh conditions along with the protection of sensitive functional groups, which on deprotection leads to generation of a large amount of byproducts. Immobilization of nitrile hydratase using a novel support reduces the cost and allows green processes. In this work, enantioselective hydrolysis of rac-mandelonitrile was studied using poly(vinyl alcohol) (PVA)/chitosan−glutaraldehyde cross-linked Rhodococcus rhodochrous ATCC BAA-870 nitrile hydratase (NHase). Immobilized NHase converted rac-mandelonitrile to (R)-amide by dynamic kinetic resolution with enantiomeric excess (ee) up to 81%. The temperature of 40 °C and pH 8 were found to be optimum for the enantioselective nitrile hydrolysis. In the presence of various cosolvents, immobilized NHase showed higher retention of activity in methanol compared to other cosolvents. The kinetic constants for free and immobilized enzyme were obtained from the Lineweaver−Burk plot. The immobilized NHase was found to be reusable up to nine successive batch reactions.

One-Dimensional 13C NMR Is a Simple and Highly Quantitative Method for Enantiodiscrimination

“…Several high-performance liquid chromatography (HPLC) methods have been described in which different types of chiral stationary phases (CSPs) are used: Chiralcel OB-H [ 18 ], Chiralcel OJ-H [ 19 , 20 , 21 , 22 ], Sumichiral OA-4400 [ 23 ], Chiralpak IA [ 24 ] and Chiralcel OD-H [ 25 ]. These stationary phases were used in combination with either mixtures of n-hexane and isopropanol [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ], n-hexane, ethanol and 1,2-dichloroethane [ 23 ], or n-hexane, isopropanol and trifluoroacetic acid [ 24 ]. By means of these chiral HPLC methods, enantiomeric excess values of mandelonitrile up to 99% could be established [ 18 , 20 ].…”

Kinetics and mechanism of regioselective monoacetylation of 3-aryloxy-1,2-propandiols using immobilized Candida antarctica lipase

“…The prevalent application of biocatalysis in non-aqueous 10 media has included stereo-selective synthesis of enantiopure 11 drugs over the past two decades [1][2][3][4]. The production of 12 enantiomerically pure compounds has gained significant impor- 13 tance in chemical and pharmaceutical industry.…”

Simulation and optimization of Novozym 40086 kinetic resolution of α‐cyclopentylphenylacetic acid enantiomers

“…An increase of temperature enhances the chance of collisions and an increase in c with temperature was observed. However, at excessive temperatures, the 3D structure of the enzyme may be destroyed, and the binding of enzyme to substrate become weak, which lead to a decrease in c . Hence, the optimal temperature of 45 °C was selected, where ee p and c s reach their maxima.…”