Enantioselective hydrolysis of p-nitrostyrene oxide by an epoxide hydrolase preparation from Aspergillus niger
✍ Scribed by Hariharan Nellaiah; Christophe Morisseau; Alain Archelas; Roland Furstoss; Jacques C. Baratti
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 809 KB
- Volume
- 49
- Category
- Article
- ISSN
- 0006-3592
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✦ Synopsis
The epoxide hydrolase activity of Aspergillus niger was synthesized during growth of the fungus and was shown to be associated with the soluble cell fraction. An enzyme preparation was worked out which could be used in place of the whole mycelium as biocatalyst for the hydrolysis of epoxides. The effect of four different cosolvents on enzyme activity was investigated. Consequently, dimethylsulfoxide (DMSO) was selected for epoxide solubilization. The effect of temperature on both reaction rate and enzyme stability was studied in the presence of DMSO (0.2 volume ratio). A temperature of 25°C was selected for the reaction of bioconversion. With a substrate concentration of 4.5 m M a batch reactor showed that the enzyme preparation hydrolyzed paranitrostyrene oxide with very high enantioselectivity. The (S) enantiomer of the epoxide remained in the reaction mixture and showed an enantiomeric excess higher than 99%. The substrate concentration could be increased to 20 m M without affecting the enantiomeric excess and degree of conversion. Therefore, the method is potentially useful for the preparative resolution of epoxides. Application are in the field of chiral synthons which are important building blocks in organic synthesis. 0