Enhancing the catalytic potential of nitrilase from Pseudomonas putida for stereoselective nitrile hydrolysis.
(R)-mandelic acid was produced from racemic mandelonitrile using free and immobilized cells of Pseudomonas putida MTCC 5110 harbouring a stereoselective nitrilase. In addition to the optimization of culture conditions and medium components, an inducer feeding approach is suggested to achieve enhanced enzyme production and therefore higher degree of conversion of mandelonitrile. The relationship between cell growth periodicity and enzyme accumulation was also studied, and the addition of the inducer was delayed by 6 h to achieve maximum nitrilase activity. The nitrilase expression was also authenticated by the sodium dodecyl phosphate-polyacrylamide gel electrophoresis analysis. P. putida MTCC 5110 cells were further immobilized in calcium alginate, and the immobilized biocatalyst preparation was used for the enantioselective hydrolysis of mandelonitrile. The immobilized system was characterized based on the Thiele modulus (phi). Efficient biocatalyst recycling was achieved as a result of immobilization with immobilized cells exhibiting 88% conversion even after 20 batch recycles. Finally, a fed batch reaction was set up on a preparative scale to produce 1.95 g of (R)-(-)-mandelic acid with an enantiomeric excess of 98.8%.
Banerjee
Anirban
A
Department of Pharmaceutical Technology (Biotechnology), National Institute of Pharmaceutical Education and Research Sector-67, SAS Nagar, 160 062, Punjab, India.
Kaul
Praveen
P
Department of Pharmaceutical Technology (Biotechnology), National Institute of Pharmaceutical Education and Research Sector-67, SAS Nagar, 160 062, Punjab, India.
Banerjee
U C
UC
Department of Pharmaceutical Technology (Biotechnology), National Institute of Pharmaceutical Education and Research Sector-67, SAS Nagar, 160 062, Punjab, India. ucbanerjee@niper.ac.in.
D000097:Acetonitriles / Q000378:metabolism*; D000619:Aminohydrolases / Q000096:biosynthesis* / Q000378:metabolism*; D019149:Bioreactors; D018914:Cells, Immobilized; D006868:Hydrolysis; D008333:Mandelic Acids / Q000378:metabolism; D016958:Pseudomonas putida / Q000201:enzymology*; D013237:Stereoisomerism
D000097:Acetonitriles; D008333:Mandelic Acids; C045516:mandelonitrile; D000619:Aminohydrolases; C021867:nitrilase; C037938:mandelic acid