School of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
School of Physics and Astronomy and The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
Biochim Biophys Acta Biomembr. 2023 Dec;1865(8):184217. doi: 10.1016/j.bbamem.2023.184217. Epub 2023 Aug 28.
There is a growing interest in the use of microbial cell factories to produce butanol, an industrial solvent and platform chemical. Biobutanol can also be used as a biofuel and represents a cleaner and more sustainable alternative to the use of conventional fossil fuels. Solventogenic Clostridia are the most popular microorganisms used due to the native expression of butanol synthesis pathways. A major drawback to the wide scale implementation and development of these technologies is the toxicity of butanol. Various membrane properties and related functions are perturbed by the interaction of butanol with the cell membrane, causing lower yields and higher purification costs. This is ultimately why the technology remains underemployed. This study aimed to develop a deeper understanding of butanol toxicity at the membrane to determine future targets for membrane engineering. Changes to the lipidome in Clostridium saccharoperbutylacetonicum N1-4 (HMT) throughout butanol fermentation were investigated with thin layer chromatography and mass spectrometry. By the end of fermentation, levels of phosphatidylglycerol lipids had increased significantly, suggesting an important role of these lipid species in tolerance to butanol. Using membrane models and in vitro assays to investigate characteristics such as permeability, fluidity, and swelling, it was found that altering the composition of membrane models can convey tolerance to butanol, and that modulating membrane fluidity appears to be a key factor. Data presented here will ultimately help to inform rational strain engineering efforts to produce more robust strains capable of producing higher butanol titres.
人们对利用微生物细胞工厂生产丁醇越来越感兴趣，丁醇是一种工业溶剂和平台化学品。生物丁醇也可用作生物燃料，是替代传统化石燃料的更清洁、更可持续的选择。由于天然表达丁醇合成途径，产溶剂梭菌是最受欢迎的微生物。这些技术广泛实施和发展的一个主要障碍是丁醇的毒性。丁醇与细胞膜的相互作用会破坏各种膜性质和相关功能，导致产量降低和纯化成本增加。这就是为什么该技术仍未得到充分利用的原因。本研究旨在深入了解细胞膜上的丁醇毒性，以确定膜工程的未来目标。通过薄层层析和质谱法研究了 Clostridium saccharoperbutylacetonicum N1-4（HMT）在丁醇发酵过程中脂类组的变化。发酵结束时，磷脂酰甘油脂质的水平显著增加，这表明这些脂质种类在耐受丁醇方面起着重要作用。通过使用膜模型和体外测定法来研究渗透性、流动性和膨胀等特性，发现改变膜模型的组成可以赋予对丁醇的耐受性，并且调节膜流动性似乎是一个关键因素。这里呈现的数据最终将有助于为生产更高丁醇产量的更稳健菌株提供合理的菌株工程努力提供信息。
