title: Continuous hydrolysis of 4-cyanopyridine by nitrilases from Fusarium solani O1 and Aspergillus niger K10.
abstract: The operational stabilities of nitrilases from Aspergillus niger K10 and Fusarium solani O1 were examined with 4-cyanopyridine as the substrate in continuous-stirred membrane reactors (CSMRs). The former enzyme was fairly stable at 30 degrees C with a deactivation constant (k (d)) and enzyme half-life of 0.014 h(-1) and 50 h, respectively, but the latter exhibited an even higher stability characterized by k (d) = 0.008 h(-1) and half-life of 87 h at 40 degrees C. Another advantage of this enzyme was its high chemoselectivity, i.e., selective transformation of nitriles into carboxylic acids, while the amide formed a high ratio of A. niger K10 nitrilase product. High conversion rates (>90%) were maintained for about 52 h using the nitrilase from F. solani O1 immobilized in cross-linked enzyme aggregates (CLEAs). The purity of isonicotinic acid was increased from 98% to >99.9% by using two CSMRs connected in series, the first one containing the F. solani O1 nitrilase and the second the amidase from Rhodococcus erythropolis A4 (both enzymes as CLEAs), the amidase hydrolyzing the by-product isonicotinamide.
authors: Department of Chemistry, Chemical Engineering and Materials, University of l'Aquila, Monteluco di Roio, 67040 l'Aquila, Italy.
authors: Anna
authors: A
authors: Malandra
authors: Maria
authors: M
authors: Cantarella
authors: Ondrej
authors: O
authors: Kaplan
authors: Vojtech
authors: V
authors: Vejvoda
authors: Bronislava
authors: B
authors: Uhnáková
authors: Barbora
authors: B
authors: Stepánková
authors: David
authors: D
authors: Kubác
authors: Ludmila
authors: L
authors: Martínková
mesh_terms: D000619:Aminohydrolases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D001234:Aspergillus niger / Q000201:enzymology*; D019149:Bioreactors; D001711:Biotransformation; D004795:Enzyme Stability; D005670:Fusarium / Q000201:enzymology*; D007539:Isonicotinic Acids / Q000378:metabolism; D007700:Kinetics; D009570:Nitriles / Q000378:metabolism*; D011725:Pyridines / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D007539:Isonicotinic Acids; D009570:Nitriles; D011725:Pyridines; C494727:4-cyanopyridine; D000619:Aminohydrolases; C021867:nitrilase