Isolation and characterization of a hexokinase mutant of Schwanniomyces castellii: Consequences on cell production in continuous culture

A mutant of Schwanniomyces castellii with reduced glucose phosphorylation and with practically no phosphorylation of fructose was investigated. Carbon catabolite represion of α-glucosidase and amylases was reduced. Repression of β-galactosidase was normal. We have compared in continuous culture this mutant strain with wild type and another previously described mutant. The relationship between the specific rate of glucose consumption (Qs) and residual glucose concentration (s) in an inverse mode, suggests that there may be two types of transport of glucose. Mutation at the phosphorylation level causes apparent modification of the kinetic parameters of glucose uptake rate. The consequence of mutation at the phosphorylation level on biomass production was discussed.