Development of a defined medium for Corynebacterium glutamicum using urea as nitrogen source.

Corynebacterium glutamicum has been widely used for bulk and fine chemicals fermentation these years. In this study, we developed a defined medium for this bacteria based on the widely used CGXII minimal medium. We evaluated the effects of different components in CGXII on cell growth of C. glutamicum ATCC 13032 and improved the medium through single-factor experiment and central composite design (CCD). Urea, K2HPO4 and MgSO4 were found to be significant factors. 7 out of the total 15 components were modified. (NH4)2SO4, KH2PO4, and protocatechuic acid were eliminated. Amounts of urea and MgSO4 were increased, and concentrations of biotin and glucose were reduced. The resulting R2 medium was proved to be more suitable for cell growth, plasmid amplification and protein production than the original recipe. Remarkably, cell biomass accumulation in R2 increased by 54.36% than CGXII. Transcriptome analysis revealed alteration of carbon metabolism, cation transport and energy synthesis, which might be beneficial for cell growth in R2. Considering the high nitrogen content and availability of urea, the new medium is simplified and cost effective, which holds attractive potential for future study. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02959-6. © King Abdulaziz City for Science and Technology 2021.