Bioconversion of benzonitrile to benzoic acid using free and agar entrapped cells of Nocardia globerula NHB-2.
The free and agar immobilized cells of Nocardia globerula NHB-2 having nitrilase (EC 3.5.5.1) activity were used to catalyse the transformation of benzonitrile to benzoic acid. The whole cells of N. globerula NHB-2 were immobilized in agar which exhibited maximum conversion of benzonitrile to benzoic acid in 0.1 M potassium phosphate buffer pH 7.5 (free cells) 8.0 (immobilized cells), temperature 40 degrees C, cells 2 mg dcm ml(-1) reaction mixture and benzonitrile (4% v/v) in 4 h (free cells). The effect of temperature on the stability of nitrilase was studied and cells retained 100% activity at 30 degrees C and lost 50% activity at 40 degrees C. In a fed batch mode of reaction 108 and 84 gl(-1) benzoic acid was produced using free and agar entrapped cells (2 g dcm). The agar immobilized cells were recycled up to three times and 80, 62, 20 gl(-1) benzoic acid was again produced respectively in each of three cycles and a total 244 g benzoic acid was produced by recycling the same mass of immobilized biocatalyst.
Raj
J
J
Department of Biotechnology, Himachal Pradesh University, Shimla, India.
Singh
N
N
Prasad
S
S
Seth
A
A
Bhalla
T C
TC
D000362:Agar; D000619:Aminohydrolases / Q000378:metabolism; D019817:Benzoic Acid / Q000378:metabolism*; D001711:Biotransformation; D018914:Cells, Immobilized; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D009570:Nitriles / Q000378:metabolism*; D009615:Nocardia / Q000378:metabolism*; D013696:Temperature
D009570:Nitriles; D019817:Benzoic Acid; D000362:Agar; C014356:benzonitrile; D000619:Aminohydrolases; C021867:nitrilase