Rational medium optimization based on comparative metabolic profiling analysis to improve fumaric acid production

• Metabolic profiling was employed to explore metabolic changes in different medium.
• Key metabolites were identified mainly responsible for fumacic acid biosynthesis.
• Rational feeding strategies were proposed for fumaric acid production improvement.
• Higher titer (56.5 g/L) was achieved by designed strategy in 7.5-L fermentor.

To rationally guide fumaric acid production improvement, metabolic profiling approach was performed to analyze metabolite changes of Rhizopus oryzae FM19 under different fermentation conditions. A correlation between the metabolic profiling and fumaric acid production was revealed by principal component analysis as well as partial least squares. Citric acid, oxaloacetic acid, 2-oxoglutarate, lactic acid, proline, alanine, valine, leucine were identified to be mainly responsible for the metabolism difference, which were involved in the Embden–Meyerhof–Parnas, tricarboxylic acid cycle, amino acid metabolism and fatty acid metabolism. Through the further analysis of metabolites changes together with the above pathways, exogenous addition strategies were developed, which resulted in 14% increase of fumaric acid (up to 56.5 g/L) and less by-products. These results demonstrated that metabolic profiling analysis could be successfully applied to the rational guidance of medium optimization and the productivity improvement of value-added compounds.