Cobalt activation of Bacillus BR449 thermostable nitrile hydratase expressed in Escherichia coli.

Expression of nitrile hydratase enzymes utilized in a new "green" process for acrylamide production has proven difficult in Escherichia coli owing to lack of a cobalt transport system to introduce the required cobalt ion into this host. We describe the expression of a thermostable nitrile hydratase from a moderate thermophile Bacillus sp. BR449 in E. coliin which the cobalt required for enzyme activation is introduced by incubation of the apoenzyme in the presence of Co++ ion at 50 degrees C, yielding active and thermostable enzyme.