Biomass crops have promise as precursors for biochemical and biofuel production. However, they contain several different types of sugar. Yeast have evolved to strongly prefer glucose as an energy source over other types of sugar. However, this preference can pose a problem.

Dried_yeast_01

Source: Mmampholo

Dried yeast used for brewing traditional beer.

Often, it is better during the biofuels production process for yeast to consume different types of sugars simultaneously. Researchers at the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI) engineered a strain of yeast that does not prefer any individual sugar. The strain simultaneously utilized multiple sugars.

The Impact

Yeasts’ preference for glucose is a challenge for manufacturers using yeast to produce biochemicals and biofuels. This research, published in Biotechnology and Bioengineering, addresses this bottleneck. It enabled yeast to convert different types of sugar simultaneously.

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This new technology will speed up the production of biochemicals and biofuels, advancing the domestic bioenergy industry. This work may also lead to more efficient production of new bioproducts. It can support industries that add value to agriculture, grow rural economies, and increase domestic energy production.

Engineered yeast

Native yeast sugar transporters have a strong glucose preference and create a bottleneck for efficient biochemical and biofuel production. These transporters were replaced by SWEET7P in engineered Saccharomyces cerevisiae capable of fermenting xylose.

This new strain successfully co-fermented glucose, mannose, fructose, and xylose in experiments with synthetic and industrial (sugarcane) media. Notably, the new strain also enables the utilization of xylitol, a common byproduct that is typically unusable by yeast. Transcriptomic and metabolomic analyses uncovered reprogramming of central carbon metabolism and less glucose preference. 

For the bioeconomy, this represents a major leap in efficiency. This accomplishment allows simultaneous sugar conversion in complex feedstocks and more efficient utilization of industrial byproducts. Enabling rapid, more efficient conversion of complex biomass crops through this approach may reduce fermentation time, minimize byproduct waste, and lower operational costs when producing biofuels and biochemicals. 

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