Acrylonitrile adaptation of Brevibacterium sp. CH1 for increased acrylamide production

Abstract A bacterial strain having higher nitrile hydratase activity and acrylonitrile concentration tolerance, numbered Brevibacterium sp. CH2, was developed by repeated subculturing of Brevibacterium sp. CH1 in the broth containing acrylonitrile with slightly increased acrylonitrile concentration. The properties of the strain were greatly improved. The specific nitrile hydratase activity of the strain increased up to 32 units mg −1 of dry cells, 3.2 times higher than that of Brevibacterium sp. CH1, and the enzyme was not inhibited by the substrate acrylonitrile concentration of 6% (v/v). The effects of temperature and pH on the activity of the free and immobilized whole cells of the strain were investigated and the substrate specificity of the strain was also studied.