| Abstract: | Methionine production by a mutant strain of Corynebacterium lilium was studied at different dilution rates and different dissolved oxygen concentrations, based on a statistical central composite design. The effect of dissolved oxygen levels between 2 % and 60 % and dilution rate levels between 0.04 to 0.29 on continuous production of methionine was studied. The process is described by the Leudeking‐Piret model. The experimentally obtained maxima for methionine and biomass productivities, observed at the same dilution rate of 0.17 h–1, also corresponds to the theoretical prediction based on this model. This experimental observation is further supported by the surface response prediction of a dilution rate of 0.16 h–1 for maximum methionine productivity and 0.15 h–1 for cell mass productivity. Also, beyond the critical value of 30 % dissolved oxygen, the apparent benefits of oxygen transfer become less significant. |
