Cyanide hydratase from Aspergillus niger K10: Overproduction in Escherichia coli, purification, characterization and use in continuous cyanide degradation

0428318 - MBÚ 2016 RIV GB eng J - Journal Article
Rinágelová, Anna - Kaplan, Ondřej - Veselá, Alicja Barbara - Chmátal, Martin - Křenková, Alena - Plíhal, Ondřej - Pasquarelli, Fabrizia - Cantarella, M. - Martínková, Ludmila
Cyanide hydratase from Aspergillus niger K10: Overproduction in Escherichia coli, purification, characterization and use in continuous cyanide degradation.
Process Biochemistry. Roč. 49, č. 3 (2014), s. 445-450. ISSN 1359-5113. E-ISSN 1873-3298
R&D Projects: GA ČR(CZ) GAP504/11/0394; GA TA ČR TA01021368
Institutional support: RVO:61388971
Keywords : Cyanide hydratase * Nitrilase * Aspergillus niger
Subject RIV: CE - Biochemistry
Impact factor: 2.516, year: 2014

A cyanide hydratase from Aspergillus niger K10 was expressed in Escherichia coil and purified. Apart from HCN, it transformed some nitriles, preferentially 2-cyanopyridine and fumaronitrile. V-max and K-m for HCN were ca. 6.8mmol min(-1) mg(-1) protein and 109mM, respectively. V-max for fumaronitrite and 2-cyanopyridine was two to three orders of magnitude lower than for HCN (ca. 18.8 and 10.3 mu.,mol min(-1) mg(-1), respectively) but K-m was also lower (ca. 14.7 and 3.7 mM, respectively). Both cyanide hydratase and nitrilase activities were abolished in truncated enzyme variants missing 18-34 C-terminal aa residues. The enzyme exhibited the highest activity at 45 degrees C and pH 8-9; it was unstable at over 35 degrees C and at below pH 5.5. The operational stability of the whole-cell catalyst was examined in continuous stirred membrane reactors with 70-mL working volume. The catalyst exhibited a half-life of 5.6 h at 28 degrees C. A reactor loaded with an excess of the catalyst was used to degrade 25 mM KCN. A conversion rate of over 80% was maintained for 3 days
Permanent Link: http://hdl.handle.net/11104/0233686