Abstract:

In the process of ethanol fermentation,Saccharomyces cerevisiae usually encounters various stress conditions,such as high temperature,high osmotic pressure and high-concentration ethanol. Aiming at these problems,the relationship between the fermentation behavior and the stress tolerance is investigated. In the investigation,the fermentation behaviors of thirteen industrial and one laboratory trial yeast strains,including the growth rate,the substrate consumption rate and the ethanol yield,are analyzed. It is found that these strains can be classified into three groups based on their fermentation behaviors. Moreover,a correlation between the fermentation behavior and the tolerance to various stresses is set up by means of the linear discriminant analysis ( LDA) ,and a growth inhibitor ( Gi) is used as a quantitative parameter to evaluate the stress tolerance of different strains. Finally,based on the tolerance and the LDA method,a statistical model is established to predict the fermentation behaviors of the strains,which lays down a novel evaluation method for the breeding and selection of S. cerevisiae.

Key words: Saccharomyces cerevisiae, stress tolerance, ethanol fermentation, linear discriminant analysis, correlation