13TSB_CRD - Flexible Engineered Solutions for Xylose Metabolism Using Synthetic Biology (FLEX)

13TSB_CRD - 使用合成生物学 (FLEX) 的木糖代谢灵活工程解决方案

• 批准号: BB/L011522/1
• 负责人: Gavin Thomas
• 金额: $ 14.1万
• 依托单位: University of York
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FL011522%2F1
• 关键词: 13TSB_CRD; Flexible; Engineered; Solutions; Xylose

The development of biofuels to replace our reliance on petrochemical-based fuels is a challenging economic problem. Basic science can make significant contributions to this problem by making the process more efficient and hence more economically competitive. The replacement of starch-based feedstock for the production of biofuels like biobutanol with more sustainable lignocellulose-based material is challenging due to the complexity of this material to efficient breakdown into forms that can used by the biofuel producing bacteria. In this project we wish to use new synthetic biology methods to engineer a whole new biological property into two biotechnologically important bacteria, namely the ability to grow on hemicellulose-derived xylo-oligomers. The formation of xylo-oligomers such as xylotetraose (X4), xylotriose (x3) and xylobiose(X2) occurs during the enzymatic breakdown of the hemicelluloses by xylanases. Further breakdown to the monosaccharide xylose (X1) requires the action of beta-xylosidases and then the free xylose is transported into bacterial cell via active transporters. The utilisation of the xylose monosaccharide has been the focus on most attention in the engineering of microbes for efficient hemicelluloses utilisation and the use of the xylo-oligomers directly has not been considered very widely. In this project we wish to engineer bacteria to use this material more efficiently. By using transporters for X2-X4, which take up one of these molecules for one unit of energy, the bacteria are much more efficient than those which have to each 2-4 units of energy to take up the same amount of sugar present in the monomeric form. There is no energetic costs to break down the X2-X4 to X1 on the inside. Bacteria growing under anaerobic fermentatative conditions used to make biobutanol are energy limited and so this will make a demonstrable increase in their growth rates as oligo-xylans are the primary carbon source available when growing on hemi-cellulose and hence these reactions have high flux. We will also investigate using a more efficient secondary transporter versus a primary ABC transporter to further improve growth yields. At a bioprocess level the use of xylo-oligomers rather than the fully hydrolysed xylose allow the use of milder chemical hydrolysis steps in the hemicelluloses pretreatment which also results in lower rates of production of chemicals that subsequently inhibit the fermentation. The xylo-oligomer clusters, Xylo4, will be created and tested in Escherichia coli and then transferred to industrial Clostridium strains used by Green Biologics that are currently being used in China by partners of Green Biologics to make butanol from lignocellulose.

开发生物燃料以取代我们对石化燃料的依赖是一个具有挑战性的经济问题。基础科学可以通过提高过程效率并因此更具经济竞争力来对这个问题做出重大贡献。用更可持续的木质纤维素基材料替代用于生产生物丁醇等生物燃料的淀粉基原料具有挑战性，因为这种材料的复杂性难以有效分解为生物燃料生产细菌可以使用的形式。在这个项目中，我们希望使用新的合成生物学方法为两种生物技术上重要的细菌设计全新的生物特性，即在半纤维素衍生的木糖低聚物上生长的能力。木寡聚物如木四糖 (X4)、木三糖 (x3) 和木二糖 (X2) 的形成发生在木聚糖酶对半纤维素的酶促分解过程中。进一步分解为单糖木糖（X1）需要β-木糖苷酶的作用，然后游离木糖通过主动转运蛋白转运到细菌细胞中。木糖单糖的利用一直是微生物工程中最受关注的焦点，以有效利用半纤维素，而直接使用木糖低聚物尚未得到广泛考虑。在这个项目中，我们希望改造细菌以更有效地利用这种材料。通过使用 X2-X4 转运蛋白（以一单位能量吸收其中一个分子），细菌比那些需要每 2-4 单位能量吸收相同量单体形式糖的细菌效率要高得多。将 X2-X4 内部分解为 X1 无需能量消耗。在用于制造生物丁醇的厌氧发酵条件下生长的细菌是能量有限的，因此这将使其生长速率明显增加，因为低聚木聚糖是在半纤维素上生长时可用的主要碳源，因此这些反应具有高通量。我们还将研究使用比初级 ABC 转运蛋白更有效的二级转运蛋白，以进一步提高生长产量。在生物工艺水平上，使用木低聚物而不是完全水解的木糖允许在半纤维素预处理中使用较温和的化学水解步骤，这也导致随后抑制发酵的化学物质的产生速率较低。木寡聚体簇 Xylo4 将在大肠杆菌中创建和测试，然后转移到 Green Biologics 使用的工业梭菌菌株中，目前 Green Biologics 的合作伙伴在中国使用该菌株从木质纤维素生产丁醇。

项目成果

Characterization of the l-arabinofuranose-specific GafABCD ABC transporter essential for l-arabinose-dependent growth of the lignocellulose-degrading bacterium Shewanella sp. ANA-3.

L-阿拉伯呋喃糖特异性GAFABCD ABC转运蛋白的表征对于木质纤维素降解细菌SHEWANELLA SP的L-阿拉伯糖依赖性生长必不可少的表征。 ana-3。

• DOI: 10.1099/mic.0.001308
• 发表时间: 2023-03
• 期刊: MICROBIOLOGY-SGM
• 影响因子: 2.8
• 作者: Drousiotis, Konstantinos;Herman, Reyme;Hawkhead, Judith;Leech, Andrew;Wilkinson, Anthony;Thomas, Gavin H
• 通讯作者: Thomas, Gavin H