Chaotropicity: a key factor in product tolerance of biofuel-producing microorganisms

Jonathan A Cray, Andrew Stevenson, Philip Ball, Sandip B Bankar, Elis Ca Eleutherio, Thaddeus C Ezeji, Rekha S Singhal, Johan M Thevelein, David J Timson, John E Hallsworth

Research output: Contribution to journalArticlepeer-review

106 Citations (Scopus)


Fermentation products can chaotropically disorder macromolecular systems and induce oxidative stress, thus inhibiting biofuel production. Recently, the chaotropic activities of ethanol, butanol and vanillin have been quantified (5.93, 37.4, 174kJkg(-1)m(-1) respectively). Use of low temperatures and/or stabilizing (kosmotropic) substances, and other approaches, can reduce, neutralize or circumvent product-chaotropicity. However, there may be limits to the alcohol concentrations that cells can tolerate; e.g. for ethanol tolerance in the most robust Saccharomyces cerevisiae strains, these are close to both the solubility limit (<25%, w/v ethanol) and the water-activity limit of the most xerotolerant strains (0.880). Nevertheless, knowledge-based strategies to mitigate or neutralize chaotropicity could lead to major improvements in rates of product formation and yields, and also therefore in the economics of biofuel production.

Original languageEnglish
Pages (from-to)228-259
Number of pages32
JournalCurrent opinion in biotechnology
Early online date02 Apr 2015
Publication statusPublished - Jun 2015


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