Efficient hydroxyproline production from glucose in minimal media by Corynebacterium glutamicum

Area of Science:

• Biotechnology
• Metabolic Engineering
• Synthetic Biology

Background:

• Expanding microbial product portfolios using whole-cell biocatalysts is crucial.
• Integrating biotransformation with central metabolism, like α-ketoglutarate-dependent oxygenase catalysis, presents challenges.
• Corynebacterium glutamicum is a versatile host for biocatalysis.

Purpose of the Study:

• To develop a method for producing trans-4-hydroxy-L-proline (Hyp) from glucose using engineered Corynebacterium glutamicum.
• To investigate the influence of isoleucine limitation on proline and Hyp production.
• To optimize fermentation conditions for efficient Hyp synthesis.

Main Methods:

• Introduction of the proline-4-hydroxylase gene from Dactylosporangium sp. into C. glutamicum.
• Cultivation under varying glucose and isoleucine concentrations in batch and continuous modes.
• Development of a high cell-density fed-batch strategy.

Main Results:

• Proline production was induced by isoleucine limitation.
• Optimal Hyp production occurred at a glucose/isoleucine molar ratio of approximately 46:1.
• A fed-batch process achieved 7.1 g/L Hyp in 23 hours with 98.5% conversion.

Conclusions:

• Fine-tuning the glucose/isoleucine ratio is key to controlling fermentation and maximizing Hyp yield.
• Engineered C. glutamicum can efficiently produce Hyp from glucose in minimal media.
• This approach enhances the utility of C. glutamicum as a biocatalyst for valuable compound production.