Deletion of the trehalose tps1 gene in Kluyveromyces lactis does not impair growth in glucose

ABSTRACT Trehalose is a non-reducing disaccharide composed of two α-glucose molecules and synthesized by an enzyme complex containing four subunits TPS1 (EC 2.4.1.15), TPS2 (EC 3.1.3.12), TPS3 and TSL1. First reports about trehalose classified this sugar as an energy reserve compound like glycogen. However, lately, trehalose is known to assist yeast cells during heat, osmotic and starvation stresses. In Saccharomyces cerevisiae, the deletion of the tps1 encoding gene eliminated the yeast ability to grow on glucose as the sole carbon source. Kluyveromyces lactis is a yeast present in various dairy products and is currently utilized for the synthesis of more than 40 industrial heterologous products. In this study, the deletion of the tps1 gene in K. lactis showed that unlike S. cerevisiae, tps1 gene disruption does not cause growth failure in glucose, galactose, or fructose. The µMAX rate values of K. lactis tps1Δ strains were equal than the non-disrupted strains, showing that the gene deletion does not affect the yeast growth. After gene disruption, the absence of trehalose into the metabolism of K. lactis was also confirmed. The absence of trehalose in Kluyveromyces lactis cells does not affect growth rates of this yeast in glucose, fructose or galactose.