초록
<P><B>Abstract</B></P> <P>In industrial fermentations, yeast cells encounter various stresses that affect the cell growth and productivity, and therefore, cells need to respond immediately to the surrounding environment. The present study helps in understanding the response of fermentative <I>Kluyveromyces marxianus</I> toward two stresses found during the fermentation of cheese whey: oxidative stress and osmotic stress. In this article, we demonstrated that <I>K. marxianus</I> cells were more resistant to oxidative and osmotic stress than <I>Saccharomyces cerevisiae</I> strains. Stationary-phase cells of both yeast strains showed more viability and higher glutathione production than cells in the exponential phase. <I>K. marxianus</I> showed high glutathione level (6.8±0.25μg/mg protein) and high intracellular glycerol (2.2±0.14g/g CDW) in 150g/L lactose, which then decreased. In addition, expression analysis was performed, and genes involved in glutathione biosynthesis and glycerol synthesis were upregulated in the presence of oxidative and osmotic stress, indicating the effect of stress protectants at the transcriptional level. We also present preliminary data regarding the use of <I>TRX</I> and <I>GSH</I> as molecular markers of oxidative and osmotic stress in <I>K. marxianus</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Glutathione plays a crucial protective role in <I>K. marxianus</I> MTCC 1389. </LI> <LI> Glutathione promotes cellular growth and viability during stress conditions. </LI> <LI> <I>K. marxianus</I> MTCC 1389 was more resistant toward stress than <I>S. cerevisiae</I> strains. </LI> <LI> The findings suggest that stress-tolerant <I>K. marxianus</I> MTCC 1389 has potential use in fermentation industries. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>