@article{bing_sulis_carey_manesh_ford_straub_laemthong_alexander_willard_jiang_et al._2024, title={Beyond low lignin: Identifying the primary barrier to plant biomass conversion by fermentative bacteria}, volume={10}, ISSN={["2375-2548"]}, url={https://www.science.org/doi/10.1126/sciadv.adq4941}, DOI={10.1126/sciadv.adq4941}, abstractNote={Renewable alternatives for nonelectrifiable fossil-derived chemicals are needed and plant matter, the most abundant biomass on Earth, provide an ideal feedstock. However, the heterogeneous polymeric composition of lignocellulose makes conversion difficult. Lignin presents a formidable barrier to fermentation of nonpretreated biomass. Extensive chemical and enzymatic treatments can liberate fermentable carbohydrates from plant biomass, but microbial routes offer many advantages, including concomitant conversion to industrial chemicals. Here, testing of lignin content of nonpretreated biomass using the cellulolytic thermophilic bacterium, Anaerocellum bescii , revealed that the primary microbial degradation barrier relates to methoxy substitutions in lignin. This contrasts with optimal lignin composition for chemical pretreatment that favors high S/G ratio and low H lignin. Genetically modified poplar trees with diverse lignin compositions confirm these findings. In addition, poplar trees with low methoxy content achieve industrially relevant levels of microbial solubilization without any pretreatments and with no impact on tree fitness in greenhouse.}, number={42}, journal={SCIENCE ADVANCES}, author={Bing, Ryan G. and Sulis, Daniel B. and Carey, Morgan J. and Manesh, Mohamad J. H. and Ford, Kathryne C. and Straub, Christopher T. and Laemthong, Tunyaboon and Alexander, Benjamin H. and Willard, Daniel J. and Jiang, Xiao and et al.}, year={2024}, month={Oct} } @article{bing_ford_willard_manesh_straub_laemthong_alexander_tanwee_hailey c. o'quinn_poole_et al._2024, title={Engineering ethanologenicity into the extremely thermophilic bacterium Anaerocellum ( f. Caldicellulosiriuptor) bescii}, volume={86}, ISSN={["1096-7184"]}, DOI={10.1016/j.ymben.2024.09.007}, journal={METABOLIC ENGINEERING}, author={Bing, Ryan G. and Ford, Kathryne C. and Willard, Daniel J. and Manesh, Mohamad J. H. and Straub, Christopher T. and Laemthong, Tunyaboon and Alexander, Benjamin H. and Tanwee, Tania and Hailey C. O'Quinn and Poole, Farris L. and et al.}, year={2024}, month={Nov}, pages={99–114} } @article{ford_teravest_buan_2023, title={The electron transport chain of Shewanella oneidensis MR-1 can operate bidirectionally to enable microbial electrosynthesis}, ISSN={["1098-5336"]}, DOI={10.1128/aem.01387-23}, abstractNote={ABSTRACT Extracellular electron transfer is a process by which bacterial cells can exchange electrons with a redox-active material located outside of the cell. In Shewanella oneidensis , this process is natively used to facilitate respiration using extracellular electron acceptors such as Fe(III) or an anode. Previously, it was demonstrated that this process can be used to drive the microbial electrosynthesis (MES) of 2,3-butanediol (2,3-BDO) in S. oneidensis exogenously expressing butanediol dehydrogenase (BDH). Electrons taken into the cell from a cathode are used to generate NADH, which in turn is used to reduce acetoin to 2,3-BDO via BDH. However, generating NADH via electron uptake from a cathode is energetically unfavorable, so NADH dehydrogenases couple the reaction to proton motive force. We therefore need to maintain the proton gradient across the membrane to sustain NADH production. This work explores accomplishing this task by bidirectional electron transfer, where electrons provided by the cathode go to both NADH formation and oxygen (O 2 ) reduction by oxidases. We show that oxidases use trace dissolved oxygen in a microaerobic bioelectrical chemical system (BES), and the translocation of protons across the membrane during O 2 reduction supports 2,3-BDO generation. Interestingly, this process is inhibited by high levels of dissolved oxygen in this system. In an aerated BES, O 2 molecules react with the strong reductant (cathode) to form reactive oxygen species, resulting in cell death. IMPORTANCE Microbial electrosynthesis (MES) is increasingly employed for the generation of specialty chemicals, such as biofuels, bioplastics, and cancer therapeutics. For these systems to be viable for industrial scale-up, it is important to understand the energetic requirements of the bacteria to mitigate unnecessary costs. This work demonstrates sustained production of an industrially relevant chemical driven by a cathode. Additionally, it optimizes a previously published system by removing any requirement for phototrophic energy, thereby removing the additional cost of providing a light source. We also demonstrate the severe impact of oxygen intrusion into bioelectrochemical systems, offering insight to future researchers aiming to work in an anaerobic environment. These studies provide insight into both the thermodynamics of electrosynthesis and the importance of the bioelectrochemical systems’ design. }, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Ford, Kathryne C. and Teravest, Michaela A. and Buan, Nicole R.}, year={2023}, month={Dec} }