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- Title
Bench scale synthesis of p-hydroxybenzoic acid using whole-cell nitrilase of Gordonia terrae mutant E9.
- Authors
Kumar, Vijay; Kumar, Virender; Thakur, Neerja; Bhalla, Tek
- Abstract
Mutants of Gordonia terrae were generated using chemical mutagens for better activity, stability and higher substrate/product tolerance of its nitrilase enzyme. Mutant E9 showed two-time increase in activity and tolerated p-hydroxybenzonitrile ( p-HBN) up to 50 mM. Response surface methodology and inducer mediation approach further enhanced the production of enzyme to 2.5-fold. The bench scale production of p-hydroxybenzoic acid ( p-HBA) was carried out in a fed-batch reaction (500-mL scale) using whole-cell nitrilase of mutant E9 in 0.1 M potassium phosphate buffer (pH 8.0) at 40 °C. Total six feedings each at an interval of 45 min resulted in accumulation of 360 mM (21.6 g) of p-HBA with a purity of 99 %. The catalytic and volumetric productivity of bioprocess using mutant G. terrae was improved to 1.8 g hg and 43.2 g L, respectively, from 0.78 g hg and 28.8 g L using resting cells of wild strain. K and V of purified nitrilase from mutant E9 were 55 U mg and 1.8 mM for p-HBN with a higher turnover number of 36 s× 10. Graphical Abstract: [Figure not available: see fulltext.]
- Subjects
NITRILASES; HYDROLASES; BENZOIC acid; HYDROXYBENZOIC acid; PHENOLIC acids
- Publication
Bioprocess & Biosystems Engineering, 2015, Vol 38, Issue 7, p1267
- ISSN
1615-7591
- Publication type
Article
- DOI
10.1007/s00449-015-1367-x