The effect of hyperosmotic stress and nitrogen starvation on growth and β-galactosidase synthesis in Kluyveromyces lactis and Kluyveromyces marxianus


Türkel S., Arik E., Güzelvardar S.

Turkish Journal of Biology, vol.32, no.3, pp.175-180, 2008 (Scopus) identifier

  • Publication Type: Article / Article
  • Volume: 32 Issue: 3
  • Publication Date: 2008
  • Journal Name: Turkish Journal of Biology
  • Journal Indexes: Scopus, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.175-180
  • Keywords: β-galactosidase, Glucose repression, Kluyveromyces, Nitrogen regulation, Osmotic stress
  • Acibadem Mehmet Ali Aydinlar University Affiliated: No

Abstract

Kluyveromyces lactis and Kluyveromyces marxianus are industrial yeasts widely used in the production of the β-galactosidase enzyme. Biosynthesis of β-galactosidase is controlled by glucose repression. In this study it was demonstrated that the derepression of β-galactosidase biosynthesis in these yeast strains is inhibited by high osmotic stress. It was found that the β-galactosidase activity of K. lactis and K. marxianus remained approximately at the repressed level when these yeast cells were subjected to NaCl-, KCl-, or sucrose-induced high osmotic stress. Derepression of β-galactosidase biosynthesis seems to be more sensitive to high osmotic stress in K. marxianus than in K. lactis. In addition, it was shown that nitrogen starvation resulted in a significant decrease in the level of β-galactosidase biosynthesis in K. lactis, while nitrogen starvation led to a 2-fold increase in β-galactosidase biosynthesis in K. marxianus. Results of this study indicated that high levels of NaCl, but not sucrose, inhibited the growth of K. lactis and K. marxianus. © TÜBİTAK.