Huang Shu, Saad Imran Syed Muhammad, Lanahan Anthony A, Hammer Sarah K, Lubner Carolyn E, Lynd Lee R, Olson Daniel G
Thayer School of Engineering at Dartmouth College, Hanover, New Hampshire, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.
Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA.
J Biol Chem. 2025 May 21;301(7):110263. doi: 10.1016/j.jbc.2025.110263.
Biofuel production from lignocellulosic biomass offers a transformative solution to reduce global fossil fuel dependency. Certain thermophilic anaerobes, including Clostridium thermocellum, show promise for renewable ethanol production due to their ability to break down plant material at high temperatures. However, achieving commercially viable ethanol yields has proven challenging despite extensive engineering efforts. Here, we characterized 27 ferredoxin:NADP oxidoreductase (Fnor) enzymes for their enzyme activity, nicotinamide cofactor specificity, thermotolerance, and functional expression in C. thermocellum. We identified a subset of 10 of these enzymes as a novel class of Fnor enzymes suited for metabolic pathways aimed at high-titer ethanol production. When expressed in engineered C. thermocellum, these enzymes increased ethanol production up to 2.2-fold. These findings establish a novel ethanol pathway and provide insights into physiological roles and biotechnological applications of this new class of Fnor enzymes.
利用木质纤维素生物质生产生物燃料为减少全球对化石燃料的依赖提供了一种变革性解决方案。某些嗜热厌氧菌，包括热纤梭菌，因其能够在高温下分解植物材料而在可再生乙醇生产方面展现出潜力。然而，尽管进行了大量工程努力，但要实现具有商业可行性的乙醇产量仍具有挑战性。在此，我们对27种铁氧化还原蛋白：NADP氧化还原酶（Fnor）进行了酶活性、烟酰胺辅因子特异性、耐热性以及在热纤梭菌中的功能表达特性分析。我们将其中10种酶鉴定为一类新型的Fnor酶，适用于旨在实现高滴度乙醇生产的代谢途径。当在工程改造的热纤梭菌中表达时，这些酶使乙醇产量提高了2.2倍。这些发现建立了一条新的乙醇途径，并为这类新型Fnor酶的生理作用和生物技术应用提供了见解。
