Nitrile hydratase of Rhodococcus erythropolis: characterization of the enzyme and the use of whole cells for biotransformation of nitriles.
The intracellular cobalt-type nitrile hydratase was purified from the bacterium Rhodococcuserythropolis. The pure enzyme consisted of two subunits of 29 and 30 kDa. The molecular weight of the native enzyme was estimated to be 65 kDa. At 25 °C the enzyme had a half-life of 25 h. The Michaelis-Menten constants Kmand vmaxfor the enzyme were 0.624 mM and 5.12 μmol/min/mg, respectively, using 3-cyanopyridine as the substrate. The enzyme-containing freely-suspended bacterial cells and the cells immobilized within alginate beads were evaluated for converting the various nitriles to amides. In a packed bed reactor, alginate beads (2 % alginate; 3 mm bead diameter) containing 200 mg/mL of cells, achieved a conversion of >90 % for benzonitrile and 4-cyanopyridine in 38 h (25 °C, pH 7.0) at a feed substrate concentration of 100 mM. The beads could be reused for up to six reaction cycles.
Department of Pharmaceutical Technology (Biotechnology), National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, Mohali, 160062, Punjab, India.
Ashwini L
AL
Kamble
Department of Pharmaceutical Technology (Biotechnology), National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, Mohali, 160062, Punjab, India.
Linga
L
Banoth
Department of Pharmaceutical Technology (Biotechnology), National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, Mohali, 160062, Punjab, India.
Vachan Singh
VS
Meena
Department of Pharmaceutical Technology (Biotechnology), National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, Mohali, 160062, Punjab, India.
Amit
A
Singh
School of Engineering, Massey University, Private Bag 11 222, Palmerston North, New Zealand.
Yusuf
Y
Chisti
Department of Pharmaceutical Technology (Biotechnology), National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, Mohali, 160062, Punjab, India. ucbanerjee@niper.ac.in.
U C
UC
Banerjee
Amides; Biotransformations; Nitrile hydratase; Nitriles; Rhodococcus erythropolis