Indexed on: 01 Apr '90Published on: 01 Apr '90Published in: Journal of industrial microbiology
3-cyanopyridine was hydrated to nicotinamide by whole cells ofBrevibacterium R-312 containing nitrile hydratase. Cells used for kinetic studies had an initial activity of 0.30 mg nicotinamide/mg cells(dry)-min and storage half-lives (pH 8) of approximately 100 days, 10 days, 5 days and less than 1 day at 4°C, 10°C, 25°C, and 30°C respectively. Temperature and pH maxima were 35°C and 8.0, respectively. Fermentations gave a maximum total hydratase activity of 1.25 mg nicotinamide/min, but at this maximum the amidase activity was unacceptably high (25% of the hydratase activity): nicotinamide was converted too rapidly to nicotinic acid. But systematic fermentation studies (7 1) showed that harvesting at mid-log phase (18–20 h) prior to the attainment of maximum total activity gave reasonably high levels of hydratase (0.3 mg nicotinamide/mg cells-min) and acceptable levels of amidase (0.03 mg nicotinic acid/mg cells-min).