Protective Effects of Melatonin on Saccharomyces cerevisiae under Ethanol Stress

Abstract

During alcoholic fermentation, Saccharomyces cerevisiae is subjected to several stresses, among which ethanol is of capital importance. Melatonin, a bioactive molecule synthesized by yeast during alcoholic fermentation, has an antioxidant role and is proposed to contribute to counteracting fermentation-associated stresses. The aim of this study was to unravel the protective effect of melatonin on yeast cells subjected to ethanol stress. For that purpose, the effect of ethanol concentrations (6 to 12%) on a wine strain and a lab strain of S. cerevisiae was evaluated, monitoring the viability, growth capacity, mortality, and several indicators of oxidative stress over time, such as reactive oxygen species (ROS) accumulation, lipid peroxidation, and the activity of catalase and superoxide dismutase enzymes. In general, ethanol exposure reduced the cell growth of S. cerevisiae and increased mortality, ROS accumulation, lipid peroxidation and antioxidant enzyme activity. Melatonin supplementation softened the effect of ethanol, enhancing cell growth and decreasing oxidative damage by lowering ROS accumulation, lipid peroxidation, and antioxidant enzyme activities. However, the effects of melatonin were dependent on strain, melatonin concentration, and growth phase. The results of this study indicate that melatonin has a protective role against mild ethanol stress, mainly by reducing the oxidative stress triggered by this alcohol.

Protecting Saccharomyces cerevisiae Cells with Nanozymes to Increase Alcohol Production

“…However, the YPD medium used in this study contained only 20 g L –1 glucose, which was insufficient to produce high osmotic stress. Furthermore, the ethanol concentration in the fermentation product (∼0.78%) was far below the commonly used 6% ethanol content for ethanol stress experiments and also below the upper limit of 13% ethanol concentration in fermentation solutions specified by ethanol production plants . In this experiment, yeast was completely exposed to a high oxygen environment during the initial phase of fermentation, suggesting that ROS in the fermentation solution may primarily originate from the mitochondrial respiratory chain .…”

“…Notably, among the four nanozymes, FeN 3 P-SAzyme exhibited the highest SODlike activity. Prior research has indicated that SOD was activated before CAT in yeast cells under stress conditions, 11 as CAT was responsible for detoxifying H 2 O 2 generated from the conversion of •O 2 − by SOD. 59 Consequently, the presence of nanozymes in the fermentation environment facilitated the early elimination of •O 2 − by cells, with the resulting H 2 O 2 promoting the activation of endogenous CAT in cells.…”

“…Numerous research approaches have been developed to address this issue, including the addition of bioactive molecules with antioxidant effects, 11 the construction of engineered yeast strains with enhanced tolerance, 12 and so forth. However, these methodologies are hindered by short service life, substantial expenses, intricate preparatory steps, and extended cycles of preparation.…”

Involvement of the High-Osmolarity Glycerol Pathway of Saccharomyces Cerevisiae in Protection against Copper Toxicity

“…The amount of MDA, the activities of SOD, and the GSH level were determined using commercial kits (Nanjing Jiancheng., Nanjing, China). MDA was determined based on the spectrophotometer measurement of the red complex produced during the reaction of thiobarbituric acid (TBA) with the MDA [ 18 ]. The cellular MDA was expressed as nmol/mg of cellular protein.…”

Engineering a GPCR-based yeast biosensor for a highly sensitive melatonin detection from fermented beverages

“…Most of the strains with the highest melatonin production belong to S. cerevisiae, among which those isolated from wine-related environments stand out. Melatonin synthesis in yeast have been associated with an antioxidant role [29][30][31] and a protective molecule against ethanol stress [32]. Wine fermentation is a very stressful process which can promote the adaptation to this harsh environment by promoting the synthesis of these protective molecules against the multiple stresses.…”