Artificial Transport Complex Improves Substrate Use in Yeast

Microorganisms such as baker's yeast can be compared to miniature factories. The raw materials, usually sugars, are converted in a multi-stage process with the help of enzymes. Microbes generate desirable products along with many by-products. Various enzymes compete for sugar whereby different building blocks important for the cell's survival are formed.

Thomas Thomik and Dr. Mislav Oreb of Goethe University Frankfurt have succeeded in engineering the metabolism of baker's yeast to use sugar more productively. The team constructed an artificial complex between a sugar transporter and a heterologous xylose isomerase in Saccharomyces cerevisiae. This new mechanism made transport proteins deliver the raw materials directly to the enzymes, resulting in accelerated xylose conversion into ethanol and diminished the production of the by-product, xylitol.