Comparative heat shock response of wild yeast isolated from spontaneous mezcal fermentation and controlled laboratory yeast (1011.2)

Abstract

The yeast manufacture is one of the oldest and the most widespread technologies in the field of industrial biotechnology, but yeast are subjected to many types of stress. These range from the physical to the chemical, secondary metabolite toxicity and heat. Oxidative stress plays a major role in the lethal effect of heat in yeast. This stress generates reduced forms of molecular oxygen, known as reactive oxygen species (ROS). In this work, we study the capacity to tolerate heat shock, production of ROS and their relation with mitochondrial respiratory electron transport, lipoperoxidation and glutathione production, of different yeast strains, isolated from spontaneous mezcal fermentation, two Kluyveromyces marxianus (OFF1 and SLP1), one Saccharomyces cerevisiae (MC4) and one controlled laboratory yeast S. cerevisiae (W303‐1A). Results observed different growth kinetics and growth rate, where the strains of K. marxianus showed faster growth. The strain SLP1 showed the best growing at 40 °C and the rest of the strains at 30 °C. The yeasts more tolerant to heat (OFF1 and SLP1) showed the biggest mitochondrial membrane potential. The higher resistance heat strain SLP1 exhibited the lesser lipoperoxidation and bigger glutathione production of the strain. The results suggest that the wild strains, mainly SLP1 strain, may differ from the responses to heat shock that have been characterized for W303‐1A. Acknowledgements: The authors appreciate the partial economic support grants from CIC‐UMSNH (2.16 to ASM), CONACYT (169093 to ASM). JMB is CONACYT fellow.