Destressing Yeast for Higher Biofuel Yields: Can Excess Chaotropicity Be Mitigated?

David J. Timson, Joshua Eardley

Research output: Contribution to journalArticlepeer-review


Biofuels have the capacity to contribute to carbon dioxide emission reduction and to energy security as oil reserves diminish and/or become concentrated in politically unstable regions. However, challenges exist in obtaining the maximum yield from industrial fermentations. One challenge arises from the nature of alcohols. These compounds are chaotropic (i.e. causes disorder in the system) which causes stress in the microbes producing the biofuel. Brewer’s yeast (Saccharomyces cerevisiae) typically cannot grow at ethanol concentration much above 17% (v/v). Mitigation of these properties has the potential to increase yield. Previously, we have explored the effects of chaotropes on model enzyme systems and attempted (largely unsuccessfully) to offset these effects by kosmotropes (compounds which increase the order of the system, i.e. the “opposite” of chaotropes). Here we present some theoretical results which suggest that high molecular mass polyethylene glycols may be the most effective kosmotropic additives in terms of both efficacy and cost. The assumptions and limitations of these calculations are also presented. A deeper understanding of the effects of chaotropes on biofuel-producing microbes is likely to inform improvements in bioethanol yields and enable more rational approaches to the “neutralisation” of chaotropicity.

Original languageEnglish
Pages (from-to)1368-1375
Number of pages8
JournalApplied Biochemistry and Biotechnology
Issue number4
Publication statusPublished - 17 Aug 2020

Bibliographical note

This is a post-peer-review, pre-copyedit version of an article published in Applied Biochemistry and Biotechnology. The final authenticated version is available online at:


  • Bioenergy
  • Bioethanol
  • Biofuel yield
  • Chaotropicity
  • Fermentation
  • Kosmotropicity


Dive into the research topics of 'Destressing Yeast for Higher Biofuel Yields: Can Excess Chaotropicity Be Mitigated?'. Together they form a unique fingerprint.

Cite this