An industrial clavulanic acid (CA) overproducer Streptomyces clavuligerus strain, namely DEPA, was engineered to further enhance its CA production. Single or multiple copies of ccaR, claR (pathway-specific activators), and cas2 (CA synthase) genes under the control of different promoters were introduced into this strain. | Turkish Journal of Biology Turk J Biol (2017) 41: 342-353 © TÜBİTAK doi: Research Article Genetic engineering of an industrial strain of Streptomyces clavuligerus for further enhancement of clavulanic acid production 1,2, 1,3 1,4 1,5 1 Aslıhan KURT KIZILDOĞAN *, Güliz VANLI JACCARD , Alper MUTLU , İbrahim SERTDEMİR , Gülay ÖZCENGİZ 1 Department of Biological Sciences, Faculty of Arts and Science, Middle East Technical University, Ankara, Turkey 2 Department of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayıs University, Samsun, Turkey 3 Department of Physiology, University of Lausanne, Lausanne, Switzerland 4 Center for Quantitative Analysis of Molecular and Cellular Biosystems (BIOQUANT), University of Heidelberg, Heidelberg, Germany 5 Department of Molecular Biology-Genetics and Biotechnology, Graduate School of Science Engineering and Technology, İstanbul Technical University, İstanbul, Turkey Received: Accepted/Published Online: Final Version: Abstract: An industrial clavulanic acid (CA) overproducer Streptomyces clavuligerus strain, namely DEPA, was engineered to further enhance its CA production. Single or multiple copies of ccaR, claR (pathway-specific activators), and cas2 (CA synthase) genes under the control of different promoters were introduced into this strain. CA titers of the resulting recombinants were analyzed by HPLC in a dynamic fashion and compared to the vector-only controls and a wild-type strain of S. clavuligerus while their growth was monitored throughout fermentation. The addition of an extra copy of ccaR, under control of its own promoter or constitutive ermE* promoter (PermE*), led to and increased volumetric levels of CA in respective recombinants, namely the AK9 and ID3 strains. Its highly stable multicopy expression by the glpF promoter (PglpF) provided up to enhanced volumetric CA titers in
