FIG 1.

Cellular NADPH balance. (a) Metabolic flux distribution in B. subtilis wild type, estimated by ¹³C flux ratio analysis and metabolite balancing. Flux values are normalized to the glucose uptake rate (q_glc; mmol gCDW⁻¹ h⁻¹), and arrow sizes scale with flux magnitudes. (b) NADPH balances of wild-type and malic enzyme deletion strains. NADPH production is calculated by summing the flux rates of NADPH-dependent glucose-6-phosphate dehydrogenase (green), 6-phosphogluconate dehydrogenase (yellow), isocitrate dehydrogenase (red), and NADP⁺ specific malic enzyme (blue) and compared to normalized growth-dependent NADPH consumption (gray).