Bench scale production of butyramide using free and immobilized cells of Bacillus sp. APB-6

Butyramide is a commodity chemical having wide range of applications from material science to biological sciences including synthesis of therapeutic drugs, hydroxamic acids, and electrorheological fluids. The nitrile hydratase protein of Bacillus sp. APB-6 was explored to develop an efficient biocatalytic process for the biotransformation of butyronitrile to butyramide using free and immobilized cells. The reaction conditions for nitrile hydratase activity were not affected after immobilization of the free cells and the optimum pH and temperature for both free and immobilized cells were 8.0 and 55 °C, respectively. In a 1–l batch reaction, complete conversion of 3000 mM butyronitrile to butyramide was achieved using free and immobilized cells. Immobilization of the cells further enhanced their operational stability and reusability in repetitive cycles of butyramide production. This bioconversion resulted in the formation of butyramide at a rate of 522.0 g h⁻¹ g⁻¹ dcw.