Optimisation of culture conditions for hyper production of nitrile hydratase by Rhodococcus rhodochrous PA-34

Rhodococcus rhodochrous PA-34 produces a nitrile hydratase (NHase, EC 4.2.1.84), which catalyses the hydration of 3-cyanopyridine to give nicotinamide. The cultural conditions for R. rhodochrous PA-34 to produce nitrile hydratase were optimised. The optimised medium containing gL^-1: glycerol, 10; peptone, 5; malt extract, 3; yeast extract, 3; CoCl₂.6H₂O, 0.025 and pH 7 proved to be suitable for the production of this enzyme by R. rhodochrous PA-34 in 36 h of incubation. Sequential addition of propionitrile as inducer enhanced the production of enzyme. The other conditions for optimum production were incubation at 30°C pH, 7 and 3% (v/v) inoculum having optical density, 0.8 – 1 at 600nm. About 12 fold increase in NHase activity was observed with optimised cultural conditions.