Uptake of iron by Kluyveromyces marxianus DSM 5422 cultivated in a whey‐based medium

The ability of Kluyveromyces marxianus for converting lactose into ethyl acetate offers a chance for the economical reuse of whey. Iron plays a significant role in this process as ester synthesis requires a low intracellular iron content, x Fe . The iron content in turn is decreased by growth due to cell expansion and increased by iron uptake. Thus, the iron‐uptake rate, ψ , is important for the considered process. Iron uptake by K. marxianus DSM 5422 was studied in aerobic cultivation on a whey‐borne medium with varied initial iron content, in part combined with a feed of iron under intensive growth conditions. A possible precipitation of iron that would pretend iron uptake was verified not to have occurred. Regularly measured dissolved iron concentrations, C Fe,L , allowed the x Fe and ψ parameters to be obtained by model‐based iron balancing. The achieved data were used for establishing a ψ ( C Fe,L , x Fe ) model. Mathematical simulations based on this iron‐uptake model reproduced the performed cultivation processes. The created iron‐uptake model allows for a future predictive system to be developed for the optimization of biotechnological ester production.