• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.146-152
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• 2010

Streptomyces clavuligerus NRRL3585 produces a clinically important $\beta$-lactamase inhibitor, clavulanic acid (CA). In order to increase the production of CA, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene (gap) was deleted in S. clavuligerus NRRL3585 to overcome the limited glyceraldehyde-3-phosphate pool; the replicative and integrative expressions of ccaR (specific regulator of the CA biosynthetic operon) and claR (Lys-type transcriptional activator) genes were transformed together into a deletion mutant to improve clavulanic acid production. We constructed two recombinant plasmids to enhance the production of CA in the gap1 deletion mutant of S. clavuligerus NRRL3585: pHN11 was constructed for overexpression of ccaR-claR, whereas pHN12 was constructed for their chromosomal integration. Both pHN11 and pHN12 transformants enhanced the production of CA by 2.59-fold and 5.85-fold, respectively, compared with the gap1 deletion mutant. For further enhancement of CA, we fed the pHN11 and pHN12 transformants ornithine and glycerol. Compared with the gap1 deletion mutant, ornithine increased CA production by 3.24- and 6.51-fold in the pHN11 and pHN12 transformants, respectively, glycerol increased CA by 2.96- and 6.21-fold, respectively, and ornithine and glycerol together increased CA by 3.72- and 7.02-fold, respectively.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.2
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• pp.116-120
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• 2006

We constructed four recombinant plasm ids to enhance the production of clavulanic acid (CA) in Streptomyces clavuligerus NRRL3585: (1) pIBRHL1, which includes ccaR, a pathway-specific regulatory gene involved in cephamycin C and CA biosynthesis; (2) pIBRHL2, containing claR, again a regulatory gene, which controls the late steps of CA biosynthesis; (3) pGIBR containing afsR-p, a global regulatory gene from Streptomyces peucetius; and (4) pKS, which harbors all of the genes (ccaR/ claR/ afsR-p). The plasmids were expressed in S. clavuligerus NRRL3585 along with the $ermE^*$ promoter. All of them enhanced the production of CA; 2.5-fold overproduction for pIBRHL1, 1.5-fold for pIBRHL2, 1.6-fold for pGIBR, and 1.5-fold for pKS compared to the wild type.

• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1538-1545
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• 2007

Clavulanic acid (CA) is an inhibitor of ${\beta}$-lactamase that is produced from Streptomyces clavuligerus NRRL3585 and is used in combination with other antibiotics in clinical treatments. In order to increase the production of CA, the replicative and integrative expressions of ccaR (encoding for a specific regulator of the CA biosynthetic operon) and cas2 (encoding for the rate-limiting enzyme in the CA biosynthetic pathway) were applied. Six recombinant plasmids were designed for this study. The pIBRHL1, pIBRHL3, and pIBRHL13 were constructed for overexpression, whereas pNQ3, pNQ2, and pNQ1 were constructed for chromosomal integration with ccaR, cas2, and ccaR-cas2, respectively. All of these plasmids were transformed into S. clavuligerus NRRL3585. CA production in transformants resulted in a significantly enhanced amount greater than that of the wild type, a 2.25-fold increase with pIBRHLl, a 9.28-fold increase with pNQ3, a 5.06-fold increase with pIBRHL3, a 2.93-fold increase with pNQ2 integration, a 5.79-fold increase with pIBRHLl3, and a 23.8-fold increase with pNQ1. The integrative pNQl strain has been successfully applied to enhance production.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.687-687
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• 2005