Enhancement of vitamin B₆ production driven by omics analysis combined with fermentation optimization

Microbial engineering aims to enhance the ability of bacteria to produce valuable products, including vitamin B₆ for various applications. Numerous microorganisms naturally produce vitamin B₆, yet the metabolic pathways involved are rigorously controlled. This regulation by the accumulation of vitamin B₆ poses a challenge in constructing an efficient cell factory.

In this study, we conducted transcriptome and metabolome analyses to investigate the effects of the accumulation of pyridoxine, which is the major commercial form of vitamin B₆, on cellular processes in Escherichia coli. Our omics analysis revealed associations between pyridoxine and amino acids, as well as the tricarboxylic acid (TCA) cycle. Based on these findings, we identified potential targets for fermentation optimization, including succinate, amino acids, and the carbon-to-nitrogen (C/N) ratio. Through targeted modifications, we achieved pyridoxine titers of approximately 514 mg/L in shake flasks and 1.95 g/L in fed-batch fermentation.

Our results provide insights into pyridoxine biosynthesis within the cellular metabolic network for the first time. Our comprehensive analysis revealed that the fermentation process resulted in a remarkable final yield of 1.95 g/L pyridoxine, the highest reported yield to date. This work lays a foundation for the green industrial production of vitamin B₆ in the future.