title: Improvement of clavulanic acid production in Streptomyces clavuligerus by genetic manipulation of structural biosynthesis genes.
abstract: To enhance clavulanic acid production, four structural clavulanic acid biosynthesis genes, carboxyethylarginine synthase (ceas2), β-lactam synthetase (bls2), clavaminate synthase (cas2) and proclavaminate amidinohydrolase (pah2), were amplified from Streptomyces clavuligerus genomic DNA. They were cloned in the pSET152 integration and pIBR25 expression vectors containing the strong ermE* promoter to generate pHN18 and pHN19, respectively, and both plasmids were introduced into S. clavuligerus by protoplast transformation. Clavulanic acid production was increased by 8.7-fold (to ~310 mg/l) in integrative pHN18 transformants and by 5.1-fold in pHN19 transformants compared to controls. Transcriptional analyses showed that the expression levels of ceas2, bls2, cas2 and pah2 were markedly increased in both transformants as compared with wild-type. The elevation of the ceas2, bls2, cas2 and pah2 transcripts was consistent with the enhanced production of clavulanic acid.
authors.affiliation: Department of Pharmaceutical Engineering, SunMoon University, Asansi, Chungnam, 336-708, Korea.
authors.forename: Hum Nath
authors.initials: HN
authors.lastname: Jnawali
authors.forename: Jin Cheol
authors.initials: JC
authors.lastname: Yoo
authors.forename: Jae Kyung
authors.initials: JK
authors.lastname: Sohng
mesh_terms: D000581:Amidohydrolases / Q000235:genetics / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000096:biosynthesis; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001709:Biotechnology; D019818:Clavulanic Acid / Q000096:biosynthesis*; D015870:Gene Expression; D005798:Genes, Bacterial; D005818:Genetic Engineering; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D013302:Streptomyces / Q000235:genetics* / Q000378:metabolism*; D014512:Ureohydrolases / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D019818:Clavulanic Acid; D006899:Mixed Function Oxygenases; C066046:clavaminate synthase; D000581:Amidohydrolases; C114020:beta-lactam synthetase; D014512:Ureohydrolases; C094419:proclavaminate amidino hydrolase