Transient responses of Candida utilis to oxygen limitation: Regulation of the Kluyver effect for maltose

Abstract

The facultatively fermentative yeast Candida utilis exhibits the Kluyver effect for maltose: this disaccharide is respired and assimilated but, in contrast to glucose, it cannot be fermented. To study the mechanism of the Kluyver effect, metabolic responses of C. utilis to a transition from aerobic, sugar-limited growth to oxygen-limited conditions were studied in chemostat cultures. Unexpectedly, the initial response of maltose-grown cultures to oxygen limitation was very similar to that of glucose-grown cultures. In both cases, alcoholic fermentation occurred after a lag phase of 1 h, during which glycerol, pyruvate and D-lactate were the main fermentation products. After ca. 10 h the behaviour of the maltose- and glucose-grown cultures diverged: ethanol disappeared from the maltose-grown cultures, whereas fermentation continued in steady-state, oxygen-limited cultures grown on glucose. The disappearance of alcoholic fermentation in oxygen-limited chemostat cultures growing on maltose was not due to a repression of the synthesis of pyruvate decarboxylase and alcohol dehydrogenase. The results demonstrate that the Kluyver effect for maltose in C. utilis does not reflect an intrinsic inability of this yeast to ferment maltose, but is caused by a regulatory phenomenon that affects a key enzyme in maltose metabolism, probably the maltose carrier. The observed kinetics indicate that this regulation occurs at the level of enzyme synthesis rather than via modification of existing enzyme activity.

pH shift enhancement ofCandida utilis pyruvate decarboxylase production

“…Limited and slower rates of PDC production were observed with non-fermentable carbon sources such as maltose, citrate, acetate, and ethanol (Franzblau and Sinclair, 1983;Kaliterna et al, 1995;Weusthuis et al, 1994). Other authors have reported the induction of PDC in S. cerevisiae (Pronk et al, 1996;Sims and Barnett, 1991;Smits et al, 2000;van Dijken et al, 1993;van Hoek et al, 2000;Weusthuis et al, 1994), Kluyveromyces lactis (Destruelle et al, 1999;Zeeman et al, 2000), Rhizopus javanicus (Rosche et al, 2002a), and Zymomonas mobilis (Toh and Doelle, 1997) by manipulation of carbon source or dissolved oxygen.…”

“…Enhancement of PDC production in C. utilis has been extensively studied with increased induction under oxygen limited conditions in the presence of glucose (Franzblau and Sinclair, 1983;Kaliterna et al, 1995;Rogers, 1995, 1996;Weusthuis et al, 1994). Limited and slower rates of PDC production were observed with non-fermentable carbon sources such as maltose, citrate, acetate, and ethanol (Franzblau and Sinclair, 1983;Kaliterna et al, 1995;Weusthuis et al, 1994).…”

Respiration-Dependent Utilization of Sugars in Yeasts: a Determinant Role for Sugar Transporters

“…The present study suggests that the fermentation capacity on lactose may be increased by specifically amplifying the LAC12 gene. The wellknown Kluyver effect for maltose utilization in Candida utilis (22,43) might also involve a limited maltose transport activity of this yeast.…”

Genetic Engineering ofCandida utilisYeast for Efficient Production ofL-Lactic Acid

“…Cloning of PDC genes in C. utilis While enhancement of the production of pyruvate decarboxylase in C. utilis has been well studied in terms of culture conditions, e.g., oxygen supplied and medium pH, [35][36][37][38] the PDC genes of C. utilis (CuPDC) have not previously been identified. In the present study, we cloned a CuPDC gene.…”