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.

随着石油储备减少和/或集中在政治不稳定的地区，生物燃料有能力为减少二氧化碳排放和促进能源安全做出贡献。然而，在从工业发酵中获得最大产量方面存在挑战。一项挑战来自酒精的性质。这些化合物是离液的（即导致系统紊乱），这会导致生产生物燃料的微生物产生压力。啤酒酵母（Saccharomyces cerevisiae) 通常不能在乙醇浓度远高于 17% (v/v) 时生长。减轻这些特性有可能提高产量。之前，我们已经探索了离液剂对模型酶系统的影响，并尝试（基本上没有成功）通过离液剂（增加系统顺序的化合物，即离液剂的“相反”）来抵消这些影响。在这里，我们提出了一些理论结果，这些结果表明，就功效和成本而言，高分子量聚乙二醇可能是最有效的亲液添加剂。还介绍了这些计算的假设和限制。更深入地了解离液剂对生产生物燃料的微生物的影响可能有助于提高生物乙醇产量，并能够采取更合理的方法来“中和”离液性。