To produce acrylamide from acrylonitrile by use of a new enzyme, nitrile hydratase, a number of nitrile-utilizing microorganisms were screened for the enzyme activity by an intact cell system. An isobutyronitrile-utilizing bacterium, strain B23, showed the best productivity among 1 86 strains tested. The strain was identified taxonomically as Pseudomonas chlororaphis. The culture and reaction conditions for the production were studied for the strain. Under the optimum conditions, 400 grams/liter of acrylamide was produced in 7.5hr. The yield was nearly 100% with a trace amount of acrylic acid. The cell-free extract of the strain showed strong activity of nitrile hydratase toward acrylonitrile and extremely low activity of amidase toward acrylamide.

The distribution of phenylacetaldoxime-degrading and pyridine-3-aldoxime-degrading ability was examined with intact cells of 975 microorganisms, including 45 genera of bacteria, 11 genera of actinomyces, 22 genera of yeasts, and 37 genera of fungi, by monitoring the decrease of the aldoximes by high-pressure liquid chromatography. The abilities were found to be widely distributed in bacteria, actinomyces, fungi, and some yeasts: 98 and 107 strains degraded phenylacetaldoxime and pyridine-3-aldoxime, respectively. All of the active strains exhibited not only the aldoxime-dehydration activity to form nitrile but also nitrile-hydrolyzing activity. On the other hand, all of 19 nitrile-degrading microorganisms (13 species, 7 genera) were found to exhibit aldoxime dehydration activity. It is shown that aldoxime dehydratase and nitrile-hydrolyzing activities are widely distributed among 188 aldoxime and 19 nitrile degraders and that the enzymes were induced by aldoximes or nitriles.