Bench scale production of butyrohydroxamic acid using amidotransferase activity of amidase from whole resting cell Bacillus sp. APB-6.

Butyrohydroxamic acid is a hydroxamic acid that has various biological and pharmacological applications. This study reports the bioconversion of butyramide and hydroxylamine to butyrohydroxamic acid with the help of amidase of Bacillus sp. APB-6, which has amidotransferase activity. Optimal conditions for the reaction were determined as 100/1200 mM butyramide/hydroxylamine ratio, incubation time 5 hr, pH 9.5, temperature 55°C, and resting cell concentration of 1.578 mg dcw ml-1. Under these conditions, the complete conversion of butyramide to butyrohydroxamic acid was attained in a 50 ml flask scale. The batch reaction was preferred over fed-batch reaction for scaling up the process to a 1 L scale, and the reaction time was reduced by 30 minutes. The final product yield was 10.23 g butyrohydroxamic acid with 95% purity, volumetric productivity of 2.273 g/L/h and 1.44 g/g/h catalytic productivity. The amidase used in this study showed high amidotransferase activity along with the industrially relevant process for the production of butyrohydroxamic acid. The NMR spectrum of the recovered product confirmed its identity as butyrohydroxamic acid.