Fine-tuning the glycerol biosynthetic pathway in Saccharomyces cerevisiae to optimize the biotechnological production of bio-fuel ethanol and L-glycerol 3-phosphate (L-G3P)

• Applicant: Professorin Dr. Elke Nevoigt
• Subject Area: Microbial Ecology and Applied Microbiology
• Term: from 2007 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 36207329

Bio-ethanol is a promising alternative to fossil fuels. Among the relevant avenues to increase conversion efficiency from biomass to ethanol, we want to focus on reducing the production of the main fermentation by-product glycerol. In addition to achieving higher ethanol yield, titer and specific productivity, such a metabolic pathway modification has the additional advantage to lower the costs for product recovery and reduces waste volumes. The challenge to reduce glycerol formation lies in the fact that the glycerol biosynthetic pathway has several important functions for cell growth and stress tolerance. Therefore, it is not straightforward to completely eliminate the glycerol biosynthetic pathway, and we want to address the challenge by fine-tuning enzyme activities in order to adjust metabolic fluxes according to cells’ minimal requirements. Without tax subsidies, bio-ethanol production is currently not an economically viable process. However, the economic efficiency could be markedly improved by concomitant production of high-value co-product(s). The L-enantiomer of glycerol 3-phosphate (L-G3P), is a high-price chemical with promising applications. Our lab has been successful in accumulating this substance in S. cerevisiae by metabolic engineering. We want to further improve L-G3P accumulation, and by doing so, evaluate the possibility of adding value to yeast biomass in the concept of bio-refining. L-G3P is an intermediate of the glycerol biosynthetic pathway. Hence, studies regarding its accumulation will synergistically affect research on reducing glycerol.

• DFG Programme: Research Grants
• International Connection: France
• Participating Persons: Dr. Sandrine Alfenore; Professor Dr. Stéphane Guillouet