Engineering Key Functions Conferring Cellular Robustness: Detoxification, Membrane Permeability and Protective Metabolites in Yeast

The establishment of the so-called bioeconomy, where biomass will represent an important source of hydrocarbons, relies on the successful development of bio-processes for the production of fuels and chemicals. Lignocellulosic material will be adopted as the primary source of sugars to be converted in a biorefinery concept not to ethanol or fuels only, but to a portfolio of chemicals. Regardless of the product, robust microorganisms are a prerequisite for the feasibility of lignocellulose bioconversion.

Current research carried out by our group focuses on the yeast Saccharomyces cerevisiae and aims at investigating the molecular bases of microbial robustness. We have identified strain engineering strategies to improve robustness based on the concept of structural engineering key functions, rather than pursuing the quest of “magic bullets”, i.e. single gene-encoded properties.

In this contribution we will present our results demonstrating how detoxification, membrane permeability and protective metabolites are key functions to improve S. cerevisiae’s robustness towards lignocellulosic inhibitors. In particular, specific examples on engineering detoxification, membrane properties and protective metabolites, applied to respectively the metabolic conversion of lignin derived phenolic compounds, acetic acid tolerance and accumulation of the cellular protectant glutathione will be presented.