Asymmetric ammonolysis of (R/S)-mandelic acid by immobilized lipases via direct amidation of mandelic acid in biphasic media


YILDIRIM D. , TÜKEL S. S.

BIOCATALYSIS AND BIOTRANSFORMATION, cilt.32, ss.251-258, 2014 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 32
  • Basım Tarihi: 2014
  • Doi Numarası: 10.3109/10242422.2014.971120
  • Dergi Adı: BIOCATALYSIS AND BIOTRANSFORMATION
  • Sayfa Sayıları: ss.251-258

Özet

We have investigated the direct enantioselective amidation of mandelic acid with ammonia, catalyzed by a variety of commercial lipases including those from Candida rugosa, Mucor miehei, Pseudomonas sp., Rhizomucor miehei, and Thermomyces lanuginosus covalently immobilized onto Florisil (R) support via glutaraldehyde and polysuccinimide spacer arms. All the immobilized lipase preparations tested preferentially amidated the R isomer of mandelic acid. The highest amide yields were obtained for immobilized Pseudomonas sp. lipase preparations under the optimized reaction conditions. After 24 h of amidation, the reaction had proceeded with an excellent yield (50%) and enantiopurity (>99%). The immobilized Pseudomonas sp. lipase preparations catalyzed the amidation reaction with the same yield and enantioselectivity. The enzyme immobilized via a glutaraldehyde spacer arm showed better reusability than that immobilized via a polysuccinimide spacer arm.