Quantitative assessment of DNA damage in the industrial ethanol production strain Saccharomyces cerevisiae PE-2

Paulo César Silva,Lucília Domingues,Björn Johansson,Rui Oliveira,Tony Collins

doi:10.1093/femsyr/foy101

Abstract

Lignocellulosic hydrolysates remain one of the most abundantly used substrates for the sustainable production of second generation fuels and chemicals with Saccharomyces cerevisiae. Nevertheless, fermentation inhibitors such as acetic acid, furfural and hydroxymethylfurfural are formed during the process and can lead to slow or stuck fermentations and/or act as genotoxic agents leading to production strain genetic instability. We have developed a novel dominant deletion (DEL) cassette assay for quantification of DNA damage in both wild-type and industrial yeast strains. Using this assay, the ethanol production strain S. cerevisiae PE-2 was shown to be more resistant to hydrogen peroxide and furfural than the laboratory DEL strain RS112. Indeed, the PE-2 strain also showed a lower tendency for recombination, consistent with a more efficient DNA protection. The dominant DEL assay presented herein should prove to be a useful tool in the selection of robust yeast strains and process conditions for second generation feedstock fermentations.

Highlights

IntroductionThe prospect of a limited fossil oil supply combined with environmental concerns associated with its use suggests the need for alternative raw materials for the production of fuels and chemicals
The prospect of a limited fossil oil supply combined with environmental concerns associated with its use suggests the need for alternative raw materials for the production of fuels and chemicals.Lignocellulosic raw materials such as wood residues and sugarcane bagasse are attractive as feedstocks as they are widely available, inexpensive and can be harvested in a sustainable way (Jansen et al 2017)
The dominant DEL assay was established in a laboratory strain CEN.PK and in the ethanol production strain Saccharomyces cerevisiae PE-2 and was successfully used to measure in-vivo DNA damage by hydrogen peroxide (H2O2) and furfural

Summary

Introduction

The prospect of a limited fossil oil supply combined with environmental concerns associated with its use suggests the need for alternative raw materials for the production of fuels and chemicals. Lignocellulosic raw materials such as wood residues and sugarcane bagasse are attractive as feedstocks as they are widely available, inexpensive and can be harvested in a sustainable way (Jansen et al 2017). The standard DEL assay, established in the strain RS112, is based on auxotrophic nutritional markers, HIS3 and LEU2, which are not useful in the industrial prototrophic and often polyploid strains used in industrial fermentation. We have developed a novel version of the DEL assay, based on the loss of a dominant marker for geneticin resistance and the gain of a dominant marker for hygromycin B resistance

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