Streptomyces clavuligerus shows a strong association between TCA cycle intermediate accumulation and clavulanic acid biosynthesis

• Published in: Applied microbiology and biotechnology 2018-05, Vol.102 (9), p.4009-4023
• Main Authors: Ramirez-Malule, Howard, Junne, Stefan, Nicolás Cruz-Bournazou, Mariano, Neubauer, Peter, Ríos-Estepa, Rigoberto
• Format: Article
• Language: English
• Subjects: Accumulation; Acetic acid; Acids; Beta lactam antibiotics; Biomedical and Life Sciences; Biosynthesis; Biotechnological Products and Process Engineering; Biotechnology; Citric Acid Cycle; Clavulanic acid; Clavulanic Acid - biosynthesis; Computer networks; Cultivation; Dilution; Dosage and administration; Drug interactions; Fluctuations; Flux; Glycerol; Health aspects; Intermediates; Life Sciences; Malate; Metabolic Engineering; Metabolism; Metabolites; Microbial Genetics and Genomics; Microbiology; Observations; Streptomyces; Streptomyces - genetics; Streptomyces - metabolism; Streptomyces clavuligerus; Substrates; Tricarboxylic acid cycle
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-018-8841-8

Clavulanic acid (CA) is produced by Streptomyces clavuligerus ( S. clavuligerus ) as a secondary metabolite. Knowledge about the carbon flux distribution along the various routes that supply CA precursors would certainly provide insights about metabolic performance. In order to evaluate metabolic patterns and the possible accumulation of tricarboxylic acid (TCA) cycle intermediates during CA biosynthesis, batch and subsequent continuous cultures with steadily declining feed rates were performed with glycerol as the main substrate. The data were used to in silico explore the metabolic capabilities and the accumulation of metabolic intermediates in S. clavuligerus . While clavulanic acid accumulated at glycerol excess, it steadily decreased at declining dilution rates; CA synthesis stopped when glycerol became the limiting substrate. A strong association of succinate, oxaloacetate, malate, and acetate accumulation with CA production in S. clavuligerus was observed, and flux balance analysis (FBA) was used to describe the carbon flux distribution in the network. This combined experimental and numerical approach also identified bottlenecks during the synthesis of CA in a batch and subsequent continuous cultivation and demonstrated the importance of this type of methodologies for a more advanced understanding of metabolism; this potentially derives valuable insights for future successful metabolic engineering studies in S. clavuligerus .