A comparison of whole cell directed evolution approaches in breeding of industrial strain of Saccharomyces cerevisiae.

Objective: To reduce the fermentation cost in very high gravity fermentations of ethanol using Saccharomyces cerevisiae, whole cell directed evolution approaches were carried out.
Results: The methods used included cell ploidy manipulation, global transcription machinery engineering and genome shuffling. Ethanol production by the four methods was improved compared with the control. Notably, the ethanol yield of a strain constructed by genome shuffling was enhanced by up to 11 % more than the control reaching 120 g ethanol/l in 35 h using a very high gravity fermentation with 300 g glucose/l.
Conclusion: Genome shuffling can create strains with improved fermentation characteristics in very high gravity fermentations.