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

TÜRKEL S., Arik E., Guzelvardar S.

TURKISH JOURNAL OF BIOLOGY, cilt.32, sa.3, ss.175-180, 2008 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 32 Sayı: 3
  • Basım Tarihi: 2008
  • Dergi Adı: TURKISH JOURNAL OF BIOLOGY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, TR DİZİN (ULAKBİM)
  • Sayfa Sayıları: ss.175-180
  • Bursa Uludağ Üniversitesi Adresli: Evet

Özet

Kluyveromyces lactis and Kluyveromyces marxianus are industrial yeasts widely used in the production of the beta-galactosidase enzyme. Biosynthesis of beta-galactosicase is controlled by glucose repression. In this study it was demonstrated that the derepression of beta-galactosicase biosynthesis in these yeast strains is inhibited by high osmotic stress. It was found that the beta-galactosiclase 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 beta-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 beta-galactosidase biosynthesis in K. lactis, while nitrogen starvation led to a 2-fold increase in beta-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.