A strategy to improve protein stability by domain insertion. TEM 1 beta-lactamase (BLA) and exo-inulinase, as model target enzymes, are inserted into a hyperthermophilic maltose binding protein from Pyrococcus furiosus (PfMBP). Unlike conventional protein stabilization methods that employ mutations and recombinations, the inventive approach does not require any modification on a target protein except for its connection with a hyperthermophilic protein scaffold. For that reason, target protein substrate specificity was largely maintained, which is often modified through conventional protein stabilization methods. The insertion was achieved through gene fusion by recombinant DNA techniques.