All you can eat yeast: substitution of major hexose transporters by AtSWEET7 in Saccharomyces cerevisiae enables simultaneous utilization of multiple sugars
Yeast sugar transporters are highly evolved for optimized glucose transport, a major roadblock when it comes to utilizing non-glucose sugars in renewable feedstocks such as lignocellulosic biomass. The AtSWEET7p transporter has been identified for simultaneous transport of glucose and xylose, prevalent in plant cell wall hydrolysates. Here, we replaced endogenous hexose transporters with AtSWEET7 to construct an engineered Saccharomyces cerevisiae capable of multiple sugars with no glucose repression. The resulting strain (NKSW7-1) gained the capacity to simultaneously co-ferment glucose, xylose, mannose, and fructose in a synthetic medium, as well as the sugars in mixtures of bagasse hydrolysate and cane juice. Notably, the replacement of native sugar transporters by AtSWEET7 led to reprogramming of central carbon metabolism, activating glucose-repressed genes even in the presence of substantial amounts of glucose. Continuous culture experiments with the NKSW7-1 strain demonstrated feasibility of AtSWEET7 to disable glucose repression on other hexose or/and pentose sugar uptake. The broad transport capacity of AtSWEET7p can be utilized for achieving co-consumption of all sugars, especially in the case of emerging, underutilized, and renewable substrates. Overall design: To enable multisugar consumption in Saccharomyces cerevisiae we substituted all major hexose transporters by AtSWEET7. We further evaluated its fermentation phenotype and transcirptional changes induced by AtSWEET7 integration. For transcriptome analysis we cultered control S. cerevisiae and AtSWEET7 expressing S. cerevisaie at 5 g/L glucose condition.