We’ve been covering some important movements in the design and performance of yeast in recent weeks, including the arrival of Novozymes’ Innova drive strains. Most of the activity has been focused on 1G ethanol fermentation.

But it’s been known for a long time that engineering a high tolerance to combined feedstock + product toxicity removes a primary obstacle to high production and cost-competitive cellulosic-based products. Tolerance-enhanced yeast processes (strains + specific fermentation modifications) could leverage the established fermentation infrastructure for cellulosic economy.

Accordingly, the US Department of Energy has been supporting a project led out of MIT by principal investigator Gregory Stephanopoulos to engineer tolerance to lignocellulosic hydrolysates inyeast S. cerevisiae, the industry-dominant biocatalyst. The potential outcome? Genetically-enhanced strains and fermentation parameters capable of:ethanol (EtOH) titers of ~100 g/L from unclarified, pretreated biomass; utilizing C6 (glucose) and C5 (xylose) sugars; and producing antifreeze molecule monoethylene glycol (MEG) and other non-EtOH products from lignocellulose.

The MIT team prepared this illuminating overview of the project’s promise and progress, presented at the DOE Project Peer Review meetings.

Second Front in the Yeast Wars: The Digest’s 2018 Multi-Slide Guide to engineering cellulosic tolerance in yeast