METABOLIC FLUX ANALYSIS APPLICATIONS TO ASPERGILLUS NIGER AB1.13 CULTIVATIONS

A stoichiometric model was developed for Aspergillus niger AB1.13. Metabolic flux analysis (MFA) revealed that the pH of the medium does not affect the flux distribution of the central carbon metabolism. However, one exception could be observed regarding the oxaloacetate hydrolase (OAAH) reaction. During D-glucose and D-xylose feeding, a 6-fold and 2-fold increase in flux distribution was observed with increasing pH (ΔpH 2.5), respectively. Differences in flux with D-glucose and D-xylose as substrate were reflected in a higher demand of NADPH during D-xylose consumption. Additionally, a comparison between metabolic models revealed that the ribulose-5-phosphate epimerase (RPE) might not be expressed during D-xylose consumption.