Engineering Acidophilic Yeasts for Sustainable Chemical Production

要实现加拿大到2050年实现净零排放的宏伟目标，所有经济部门都需要开发消除温室气体(GHGs)的创新途径。化学品和燃料的生产是能源和排放密集型的，使用石化原料。因此，迫切需要开发化学品制造的替代工艺。生物工艺在较低的温度和压力下运行，具有很高的选择性，可以使用环境友好的可再生原料。然而，生物化学品的产量和浓度(滴度)通常是稀释的，需要进一步的优化来提高化学品的生产率和滴度。最近，人们对将二氧化碳作为化学品生产的原料产生了浓厚的兴趣。直接从空气中捕获二氧化碳以及随后利用可再生电力的电催化还原二氧化碳的领域引起了重大的研究关注。相对于电催化还原CO2，生物固定CO2的速率较慢。因此，一个耐人寻味的替代方案是开发混合电催化和生物化学过程，将二氧化碳转化为增值化学品。在高电流密度、高能量效率和高选择性的情况下，电催化将二氧化碳还原为甲酸、甲醇。因此，甲酸盐和甲醇是一种很有前途的电催化和生物化学混合反应的中间体。我们团队率先开发了一种新的生物化学方法来生产尼龙前体己二酸。这种生物尼龙工艺商业化的一个关键瓶颈是己二酸对葡萄糖和木糖等纤维素糖的产率较低。在这里，我们的目标是开发新型的耐酸酵母，它可以共同利用电催化衍生的甲酸盐和甲醇以及葡萄糖来获得更高的己二酸产量，从而使它们的商业可行性成为可能。

Achieving Canada's ambitious goal of net zero emissions by 2050 requires all sectors of the economy to develop innovative pathways to eliminate greenhouse gases (GHGs). Production of chemicals & fuels is energy and emissions intensive, and uses petrochemical feedstocks. Hence, there is a strong need to develop alternative processes for the manufacturing of chemicals. Bioprocesses operate at lower temperature and pressures and have high selectivity and can use environmentally friendly renewable feedstocks. However, the productivities and concentrations of biochemicals (titre) are typically dilute and require further rounds of optimization to enhance the productivity and titres of chemicals.Recently, there has been significant interest in using CO2 as a feedstock for chemicals production. The areas of direct capture of CO2 from air and the subsequent electrocatalytic reduction of CO2 using renewable electricity has attracted significant research attention. The rates of biological CO2 fixation are slower relative to electrocatalytic reduction of CO2. Hence, an intriguing alternative is the development of hybrid electrocatalytic and biochemical processes to convert CO2 into value added chemicals. Electrocatalytic reduction of CO2 to formate, methanol has demonstrated at high current densities, energy efficiency and selectivity. Therefore, formate and methanol are promising intermediates for a hybrid electrocatalytic and biochemical processes. Our group has pioneered the development of a novel biochemical pathway to produce the nylon precursor, adipic acid. A key bottleneck in the commercialization of such a bionylon process is the lower yield of adipic acid on cellulosic sugars such as glucose and xylose.Here, we aim to develop novel acid tolerant yeasts that can co-utilize electrocatalytically derived formate and methanol along with glucose to obtain adipic acid at higher yields, thereby enabling their commercial viability.