title: Applications of gene replacement technology to Streptomyces clavuligerus strain development for clavulanic acid production.
abstract: Cephamycin C production was blocked in wild-type cultures of the clavulanic acid-producing organism Streptomyces clavuligerus by targeted disruption of the gene (lat) encoding lysine epsilon-aminotransferase. Specific production of clavulanic acid increased in the lat mutants derived from the wild-type strain by 2- to 2.5-fold. Similar beneficial effects on clavulanic acid production were noted in previous studies when gene disruption was used to block the production of the non-clavulanic acid clavams produced by S. clavuligerus. Therefore, mutations in lat and in cvm1, a gene involved in clavam production, were introduced into a high-titer industrial strain of S. clavuligerus to create a double mutant with defects in production of both cephamycin C and clavams. Production of both cephamycin C and non-clavulanic acid clavams was eliminated in the double mutant, and clavulanic acid titers increased about 10% relative to those of the parental strain. This represents the first report of the successful use of genetic engineering to eliminate undesirable metabolic pathways in an industrial strain used for the production of an antibiotic important in human medicine.
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: A S
authors.initials: AS
authors.lastname: Paradkar
authors.forename: R H
authors.initials: RH
authors.lastname: Mosher
authors.forename: C
authors.initials: C
authors.lastname: Anders
authors.forename: A
authors.initials: A
authors.lastname: Griffin
authors.forename: J
authors.initials: J
authors.lastname: Griffin
authors.forename: C
authors.initials: C
authors.lastname: Hughes
authors.forename: P
authors.initials: P
authors.lastname: Greaves
authors.forename: B
authors.initials: B
authors.lastname: Barton
authors.forename: S E
authors.initials: SE
authors.lastname: Jensen
mesh_terms: D002513:Cephamycins / Q000378:metabolism; D019818:Clavulanic Acid / Q000096:biosynthesis*; D017353:Gene Deletion; D005798:Genes, Bacterial; D005818:Genetic Engineering / Q000379:methods*; D008239:Lysine / Q000378:metabolism; D013302:Streptomyces / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D000637:Transaminases / Q000235:genetics*
chemical_list: D002513:Cephamycins; D019818:Clavulanic Acid; D000637:Transaminases; D008239:Lysine; C024925:cephamycin C