EFFICIENT PRODUCTION OF ACULEACIN-A ACYLASE IN RECOMBINANT STREPTOMYCES STRAINS

The productivities of aculeacin A acylase in various recombinant Strep tomyces strains were examined. When the acylase gene was introduced in to six species (S. lividans, S. albus, S. ambofaciens, S. parvulus, S. griseus and S. avermitilis) using Streptomyces multi-copy vector pIJ7 02, all strains produced the acylase extracellularly. The recombinant S. Griseus was the most efficient producer of the enzyme, producing 25 -fold more than the original producer, Actinoplanes utahensis. On the other hand, the recombinant strains of S. lividans and S. avermitilis showed almost the same productivity as A. utahensis. The purified reco mbinant acylases from four strains, S. albus, S. ambofaciens, S. parvu lus and S. griseus, were composed of two subunits; however, the molecu lar mass values of their small subunits were higher than that of the o riginal acylase. Further, immunoblot analysis showed that the presumed precursor peptide and its degradation products were also detected in the low-producing strains, A. utahensis and S. avermitilis. These find ings indicate that the productivity of the acylase was affected by pro teolytic activity in the host strains.