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

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. | Turk J Biol 32 (2008) 175-180 © TÜB‹TAK The Effect of Hyperosmotic Stress and Nitrogen Starvation on Growth and β-Galactosidase Synthesis in Kluyveromyces lactis and Kluyveromyces marxianus Sezai TÜRKEL, Elif ARIK, Sinem GÜZELVARDAR Department of Biology, Faculty of Arts and Sciences, Uluda¤ University, 16059 Bursa - TURKEY Received: 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. Key Words: Kluyveromyces, β-galactosidase, osmotic stress, nitrogen regulation, glucose repression Yüksek Ozmotik Stres ve Azot Açl›¤›n›n Kluyveromyces lactis ve Kluyveromyces marxianus’ta Üreme H›z› ve β-Galaktozidaz Sentezine Etkileri Özet: Kluyveromyces lactis ve Kluyveromyces marxianus β-galaktozidaz enzimi üretiminde yayg›n olarak kullan›lan endüstriyel mayalard›r. β-galaktozidaz’›n biyosentezi glukoz bask›lamas› ile kontrol edilir. Bu çal›flmada β-galaktozidaz biyozentezi derepresyonunun yüksek ozmotik stress taraf›ndan inhibe edildi¤i gösterildi. K. lactis

• Sinh học
• β galactosidase
• Osmotic stress
• K
• lactis
• Nitrogen regulation
• Glucose repression
• Thermophilic βgalactosidase
• Lactose intolerance
• Galactooligo saccharides
• Bacillus Licheniformis isolated
• Anoxybacillus Flavithermus
• Carbohydrate polymers
• Protein stabilization
• Sugar glass
• Dynamic vapor sorption
• Differential scanning calorimetry
• Oxidative stress response
• Glucose repression
• Knock out deletion
• Schizosacharomyces pombe
• Git3 G protein coupled receptor
• BMC Biotechnology
• Catabolite repression
• D lactic acid
• E coli
• Glucose effect
• Xylose fermentation
• cerevisiae
• Bakers yeast strains
• Hyperosmotic stress
• Invertase activities
• Enzyme activity
• Saccharomyces cerevisiae
• Hexose transporters
• Non histone proteins
• HXT4 gene
• Hexokinase PII
• SUC2 gene
• Gcr2 and Sgc1 mutants
• BMC Molecular and Cell Biology
• Eukaryotic cells
• Transcriptional factor
• Mig2 transport