Oxygen transfer and scale‐up in lysine production by Ustilago maydis mutant

The oxygen transfer coefficient estimated by both sulfite and dynamic methods and some of the rheological properties of fermentation broths derived from the batch cultivation of a mutant of U. maydis in a sugar cane juice substrate, are used in a scaling‐up procedure on the basis of the power consumption per volume unit concept. The fluid was of the Binham plastic type; the Np ‐ N RE correlations showed that the modified Reynolds numbers of the flat‐blade turbine impellers were low, near to or in the laminar region; the Na ‐ Pg / P relations were established and then used in the calculation regardless of the geometrical dissimilarities of the vessels. A change of scale from 5 to 50 liters was calculated and operated keeping the power per volume value constant. Reproduction of lysine yields, 2.5–3.2 g/liter, was repeatedly reached in 8 successive runs.