Enhancement of resistance of Saccharomyces cerevisiae to ethanol by heterologous expression of a rice metallothionein isoform (OsMTI-1b)

Saccharomyces cerevisiae is the most important industrial yeast employed in bioethanol production. Yeast strains during fermentation are exposed to various stresses such as osmotic shock, oxidative stress and toxicity of secondary metabolites which lead to the loss of biological products. Metallothioneins are low molecular weight cysteine-rich metal-binding proteins found in a wide range of eukaryotes and are believed to play key roles in protection against oxidative stress. The main purpose of this study was to investigate the effect of heterologous expression of a rice metallothionein (MT) isoform (OsMTI-1b) on the tolerance of Saccharomyces cerevisiaeto ethanol stress. The gene encoding OsMTI-1b was cloned into p426GPD as a yeast expression vector. The new construct was transformed to competent cells of S.cerevisiae. After verification of heterologous expression of OsMTI-1b, the new strain as well as control were grown under stress conditions. In comparison to control strain the transformed S. cerevisiae cells expressing OsMTI-1b showed more tolerance to ethanol. The results indicate that heterologous expression of plant MT isofoms can be useful in enhancement of tolerance of S. cerevisiae to multiple stresses.

کلیدواژه ها:

Ethanol ، Metallothionein ، Rice ، S.cerevisiae Abbreviations: MT ، Metallothionein ، Os ، Oryza sativa ، GST ، Glutathione-S-Transferase