Stereoselective nitrile hydrolysis by immobilized whole-cell biocatalyst.
The present work attempts to deal with the stability and reusability aspect of nitrilase from Alcaligenes faecalis for the production of (R)-(-)-mandelic acid. Four entrapment matrixes were screened to search for a suitable support, and alginate was found to have significant process advantages over its other counterparts. Thermodynamic analysis allowed us to account for decreased enantioselectivity (E) as a result of immobilization. The system was also characterized based on the Thiele modulus (phi). Efficient reusability of the biocatalyst up to 35 batches was achieved by immobilization as compared to 9 batches for free cells, and cross-linking extended it further to 40 batches. Finally, synthetic utility of the immobilized biocatalyst was demonstrated on a preparative scale to produce 640 g of (R)-(-)-mandelic acid with 97% enantiomeric excess (ee).
Kaul
Praveen
P
Department of Pharmaceutical Technology, National Institute of Pharmaceutical Education and Research, Sector-67, SAS Nagar, Punjab, 160 062 India.
Banerjee
Anirban
A
Banerjee
Uttam Chand
UC