pHsh vectors, a novel expression system of Escherichia coli for the large-scale production of recombinant enzymes

Gene expression system Hsh is developed to increase enzyme production and to decrease the cost in the induction of gene expression in Escherichia coli. The vectors of Hsh system were constructed by combining a synthesized heat-shock promoter with a synthesized terminator and an origin of replication derived from pUC19 in which the expression of foreign genes was regulated by an alternative sigma factor, sigma(32) of E. coli. In comparison, the Hsh promoter gave a 2.4-fold higher production for xynIII gene encoding a xylanase than existing heat-shock inducible promoter p (L), 1.2-fold and 3-fold production for xar gene encoding a arabinosidase than trc and T-7 promoter, respectively. The flow-in-heat technique created a rapid rise in temperature for effective induction of gene expression in bioreactor scale.