High-level production of hyperthermophilic cellulase in the Bacillus brevis expression and secretion system.

A hyperthermophilic cellulase derived from Pyrococcus horikoshii was successfully produced with the Bacillus brevis host-vector system. The production of the recombinant enzyme was increased about 20-fold (to a level of 100 mg per liter) by the insertion of certain amino acid such as alanine and peptides like AEEAADP between the carboxyl end of signal peptide and the N-terminus of the mature cellulase. These recombinant cellulases had the same characteristics as that of the cellulase expressed in Escherichia coli.