[Lactate oxidation by Hansenula anomala cells].

Lactate oxidation by freeze-dried cells of Hansenula anomala was studied in the presence of exogenous electron acceptors, potassium ferricyanide (PF) and phenazine metosulfate (PMS). The product of oxidation is pyruvate. The apparent Michaelis constants for lactate, PF and PMS are 1.2, 0.6 and 0.05, respectively. The pH optimum of lactate oxidation is 8.0. The freeze-dried cells of the yeast are inactivated by 5 mM bromopyruvate by 50% within 1.5 min. Treatment of the intact cells with ultrasound activates them. The respiratory function of the cells is characterized with a KM(app.) of 0.05 mM in the presence of lactate. PF has no effect on respiration. A scheme is proposed for lactate oxidation by the cells with damaged membranes whose amount after lyophilization is 10--20%.