Updated project metadata.
Although metabolic engineering approaches have benefited the development of industrial strains enormously, they are often only partially successful, such that additional rounds of modification are generally needed to ensure microbial strains meet all the requirements of a particular process. Systems biology approaches can aid in yeast design providing an integrated view of yeast physiology and helping to identify targets for modification. Among other phenotypes, the generation of wine yeasts that are able to produce wines with reduced ethanol concentrations has been the focus of extensive research. However, while producing low-alcohol wines, these strains generally produce off-flavour metabolites as metabolic by-products. We therefore used transcriptomics, proteomics and metabolomics to investigate the physiological changes of such an engineered low-ethanol wine strain during wine fermentation to determine possible strategies for by-product remediation. Integration of ‘omics data led to the identification of several processes, including reactions related to the pyruvate node and redox homeostasis, as significantly different compared to a non-engineered parent strain, with acetaldehyde and 2,4,5-trimethyl 1,3-dioxolane identified as the main off-flavour metabolites. Gene remediation strategies were applied to decrease the formation of these metabolites, while maintaining the ‘low-alcohol’ phenotype.