Production of fumaric acid by fermentation

Area of Science:

• Biotechnology
• Industrial Microbiology
• Metabolic Engineering

Background:

• Fermentative production of fumaric acid from renewable resources presents a sustainable alternative to petrochemical methods.
• Current fumaric acid production using Rhizopus strains achieves high titers (126 g/L), productivity (1.38 g/L/h), and yield (0.97 g/g) but requires strict process control.
• Limitations of current microbial strains include pH tolerance, morphology, genetic accessibility, and carbon source versatility.

Purpose of the Study:

• To highlight the need for highly efficient fermentative processes for fumaric acid production.
• To identify key challenges and limitations associated with current fumaric acid-producing strains.
• To emphasize the importance of understanding fumaric acid export mechanisms for advancing metabolic engineering efforts.

Main Methods:

• Review of existing literature on fermentative fumaric acid production.
• Analysis of reported fermentation parameters (titer, productivity, yield).
• Identification of limitations in current microbial strains and processes.

Main Results:

• The best reported fumaric acid fermentations achieve 126 g/L titer, 1.38 g/L/h productivity, and 0.97 g/g yield on glucose.
• Essential process conditions include pH control, aeration, and carbonate/CO2 supply.
• Key limitations of Rhizopus strains involve pH tolerance, morphology, genetic tractability, and substrate flexibility.

Conclusions:

• Achieving cost-competitiveness with petrochemical fumaric acid production necessitates highly efficient fermentation processes.
• Overcoming strain limitations through metabolic engineering is critical for improving fumaric acid production.
• Understanding the energetics and export mechanisms of fumaric acid is vital for engineering alternative hosts like Escherichia coli and Saccharomyces cerevisiae.