@article{bing_willard_manesh_laemthong_crosby_adams_kelly_2023, title={Complete Genome Sequences of Caldicellulosiruptor acetigenus DSM 7040, Caldicellulosiruptor morganii DSM 8990 (RT8.B8), and Caldicellulosiruptor naganoensis DSM 8991 (NA10)}, volume={2}, ISSN={["2576-098X"]}, DOI={10.1128/mra.01292-22}, abstractNote={The genome sequences of three extremely thermophilic, lignocellulolytic Caldicellulosiruptor species were closed, improving previously reported multiple-contig assemblies. All 14 classified Caldicellulosiruptor spp. now have closed genomes. Genome closure will enhance bioinformatic analysis of the species, including identification of carbohydrate-active enzymes (CAZymes) and comparison against other Caldicellulosiruptor species and lignocellulolytic microorganisms.}, journal={MICROBIOLOGY RESOURCE ANNOUNCEMENTS}, author={Bing, Ryan G. G. and Willard, Daniel J. J. and Manesh, Mohamad J. H. and Laemthong, Tunyaboon and Crosby, James R. R. and Adams, Michael W. W. and Kelly, Robert M. M.}, year={2023}, month={Feb} }
 @article{bing_willard_manesh_laemthong_crosby_adams_kelly_2023, title={Complete Genome Sequences of Two Thermophilic Indigenous Bacteria Isolated from Wheat Straw, Thermoclostridium stercorarium subsp. Strain RKWS1 and Thermoanaerobacter sp. Strain RKWS2}, volume={12}, ISSN={["2576-098X"]}, DOI={10.1128/mra.01193-22}, abstractNote={Reported here are complete genome sequences for two anaerobic, thermophilic bacteria isolated from wheat straw, i.e., the (hemi)cellulolytic Thermoclostridium stercorarium subspecies strain RKWS1 (3,029,933 bp) and the hemicellulolytic Thermoanaerobacter species strain RKWS2 (2,827,640 bp). Discovery of indigenous thermophiles in plant biomass suggests that high-temperature microorganisms are more ubiquitous than previously thought.}, number={3}, journal={MICROBIOLOGY RESOURCE ANNOUNCEMENTS}, author={Bing, Ryan G. and Willard, Daniel J. and Manesh, Mohamad J. H. and Laemthong, Tunyaboon and Crosby, James R. and Adams, Michael W. W. and Kelly, Robert M.}, year={2023}, month={Mar} }
 @article{bing_carey_laemthong_willard_crosby_sulis_wang_adams_kelly_2023, title={Fermentative conversion of unpretreated plant biomass: A thermophilic threshold for indigenous microbial growth}, volume={367}, ISSN={["1873-2976"]}, url={http://europepmc.org/abstract/med/36347479}, DOI={10.1016/j.biortech.2022.128275}, abstractNote={Naturally occurring, microbial contaminants were found in plant biomasses from common bioenergy crops and agricultural wastes. Unexpectedly, indigenous thermophilic microbes were abundant, raising the question of whether they impact thermophilic consolidated bioprocessing fermentations that convert biomass directly into useful bioproducts. Candidate microbial platforms for biomass conversion, Acetivibrio thermocellus (basionym Clostridium thermocellum; Topt 60 °C) and Caldicellulosiruptor bescii (Topt 78 °C), each degraded a wide variety of plant biomasses, but only A. thermocellus was significantly affected by the presence of indigenous microbial populations harbored by the biomass. Indigenous microbial growth was eliminated at ≥75 °C, conditions where C. bescii thrives, but where A. thermocellus cannot survive. Therefore, 75 °C is the thermophilic threshold to avoid sterilizing pre-treatments on the biomass that prevents native microbes from competing with engineered microbes and forming undesirable by-products. Thermophiles that naturally grow at and above 75 °C offer specific advantages as platform microorganisms for biomass conversion into fuels and chemicals.}, journal={BIORESOURCE TECHNOLOGY}, author={Bing, Ryan G. and Carey, Morgan J. and Laemthong, Tunyaboon and Willard, Daniel J. and Crosby, James R. and Sulis, Daniel B. and Wang, Jack P. and Adams, Michael W. W. and Kelly, Robert M.}, year={2023}, month={Jan} }
 @article{vailionis_zhao_zhang_rodionov_lipscomb_tanwee_hailey c. o'quinn_bing_kelly_adams_et al._2023, title={Optimizing Strategies for Bio-Based Ethanol Production Using Genome-Scale Metabolic Modeling of the Hyperthermophilic Archaeon, Pyrococcus furiosus}, volume={6}, ISSN={["1098-5336"]}, DOI={10.1128/aem.00563-23}, abstractNote={A genome-scale metabolic model, encompassing a total of 623 genes, 727 reactions, and 865 metabolites, was developed for Pyrococcus furiosus, an archaeon that grows optimally at 100°C by carbohydrate and peptide fermentation. The model uses subsystem-based genome annotation, along with extensive manual curation of 237 gene-reaction associations including those involved in central carbon metabolism, amino acid metabolism, and energy metabolism. The redox and energy balance of P. furiosus was investigated through random sampling of flux distributions in the model during growth on disaccharides. The core energy balance of the model was shown to depend on high acetate production and the coupling of a sodium-dependent ATP synthase and membrane-bound hydrogenase, which generates a sodium gradient in a ferredoxin-dependent manner, aligning with existing understanding of P. furiosus metabolism. The model was utilized to inform genetic engineering designs that favor the production of ethanol over acetate by implementing an NADPH and CO-dependent energy economy. The P. furiosus model is a powerful tool for understanding the relationship between generation of end products and redox/energy balance at a systems-level that will aid in the design of optimal engineering strategies for production of bio-based chemicals and fuels. IMPORTANCE The bio-based production of organic chemicals provides a sustainable alternative to fossil-based production in the face of today's climate challenges. In this work, we present a genome-scale metabolic reconstruction of Pyrococcus furiosus, a well-established platform organism that has been engineered to produce a variety of chemicals and fuels. The metabolic model was used to design optimal engineering strategies to produce ethanol. The redox and energy balance of P. furiosus was examined in detail, which provided useful insights that will guide future engineering designs.}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Vailionis, Jason L. and Zhao, Weishu and Zhang, Ke and Rodionov, Dmitry A. and Lipscomb, Gina L. and Tanwee, Tania N. N. and Hailey C. O'Quinn and Bing, Ryan G. and Kelly, Robert M. and Adams, Michael W. W. and et al.}, year={2023}, month={Jun} }
 @article{laemthong_bing_crosby_manesh_adams_kelly_2023, title={Role of cell-substrate association during plant biomass solubilization by the extreme thermophile Caldicellulosiruptor bescii}, volume={27}, ISSN={["1433-4909"]}, DOI={10.1007/s00792-023-01290-7}, number={1}, journal={EXTREMOPHILES}, author={Laemthong, Tunyaboon and Bing, Ryan G. and Crosby, James R. and Manesh, Mohamad J. H. and Adams, Michael W. W. and Kelly, Robert M.}, year={2023}, month={Apr} }
 @article{bing_willard_crosby_adams_kelly_2023, title={Whither the genus Caldicellulosiruptor and the order Thermoanaerobacterales: phylogeny, taxonomy, ecology, and phenotype}, volume={14}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2023.1212538}, abstractNote={The order Thermoanaerobacterales currently consists of fermentative anaerobic bacteria, including the genus Caldicellulosiruptor . Caldicellulosiruptor are represented by thirteen species; all, but one, have closed genome sequences. Interest in these extreme thermophiles has been motivated not only by their high optimal growth temperatures (≥70°C), but also by their ability to hydrolyze polysaccharides including, for some species, both xylan and microcrystalline cellulose. Caldicellulosiruptor species have been isolated from geographically diverse thermal terrestrial environments located in New Zealand, China, Russia, Iceland and North America. Evidence of their presence in other terrestrial locations is apparent from metagenomic signatures, including volcanic ash in permafrost. Here, phylogeny and taxonomy of the genus Caldicellulosiruptor was re-examined in light of new genome sequences. Based on genome analysis of 15 strains, a new order, Caldicellulosiruptorales, is proposed containing the family Caldicellulosiruptoraceae , consisting of two genera, Caldicellulosiruptor and Anaerocellum . Furthermore, the order Thermoanaerobacterales also was re-assessed, using 91 genome-sequenced strains, and should now include the family Thermoanaerobacteraceae containing the genera Thermoanaerobacter, Thermoanaerobacterium, Caldanaerobacter, the family Caldanaerobiaceae containing the genus Caldanaerobius , and the family Calorimonaceae containing the genus Calorimonas . A main outcome of ANI/AAI analysis indicates the need to reclassify several previously designated species in the Thermoanaerobacterales and Caldicellulosiruptorales by condensing them into strains of single species. Comparative genomics of carbohydrate-active enzyme inventories suggested differentiating phenotypic features, even among strains of the same species, reflecting available nutrients and ecological roles in their native biotopes.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Bing, Ryan G. G. and Willard, Daniel J. J. and Crosby, James R. R. and Adams, Michael W. W. and Kelly, Robert M. M.}, year={2023}, month={Aug} }
 @article{bing_straub_sulis_wang_adams_kelly_2022, title={<p>Plant biomass fermentation by the extreme thermophile Caldicellulosiruptor bescii for co-production of green hydrogen and acetone: Technoeconomic analysis</p>}, volume={348}, ISSN={["1873-2976"]}, url={http://europepmc.org/abstract/med/35093526}, DOI={10.1016/j.biortech.2022.126780}, abstractNote={A variety of chemical and biological processes have been proposed for conversion of sustainable low-cost feedstocks into industrial products. Here, a biorefinery concept is formulated, modeled, and analyzed in which a naturally (hemi)cellulolytic and extremely thermophilic bacterium, Caldicellulosiruptor bescii, is metabolically engineered to convert the carbohydrate content of lignocellulosic biomasses (i.e., soybean hulls, transgenic poplar) into green hydrogen and acetone. Experimental validation of C. bescii fermentative performance demonstrated 82% carbohydrate solubilization of soybean hulls and 55% for transgenic poplar. A detailed technical design, including equipment specifications, provides the basis for an economic analysis that establishes metabolic engineering targets. This robust industrial process leveraging metabolically engineered C. bescii yields 206 kg acetone and 25 kg H2 per metric ton of soybean hull, or 174 kg acetone and 21 kg H2 per metric ton transgenic poplar. Beyond this specific case, the model demonstrates industrial feasibility and economic advantages of thermophilic fermentation.}, journal={BIORESOURCE TECHNOLOGY}, author={Bing, Ryan G. and Straub, Christopher T. and Sulis, Daniel B. and Wang, Jack P. and Adams, Michel W. W. and Kelly, Robert M.}, year={2022}, month={Mar} }
 @article{crosby_laemthong_bing_zhang_tanwee_lipscomb_rodionov_zhang_adams_kelly_2022, title={Biochemical and Regulatory Analyses of Xylanolytic Regulons in Caldicellulosiruptor bescii Reveal Genus-Wide Features of Hemicellulose Utilization}, volume={10}, ISSN={["1098-5336"]}, DOI={10.1128/aem.01302-22}, abstractNote={Caldicellulosiruptor species scavenge carbohydrates from runoff containing plant biomass that enters hot springs and from grasses that grow in more moderate parts of thermal features. While only a few Caldicellulosiruptor species can degrade cellulose, all known species are hemicellulolytic. The most well-characterized species, Caldicellulosiruptor bescii, decentralizes its hemicellulase inventory across five different genomic loci and two isolated genes. Transcriptomic analyses, comparative genomics, and enzymatic characterization were utilized to assign functional roles and determine the relative importance of its six putative endoxylanases (five glycoside hydrolase family 10 [GH10] enzymes and one GH11 enzyme) and two putative exoxylanases (one GH39 and one GH3) in C. bescii. Two genus-wide conserved xylanases, C. bescii XynA (GH10) and C. bescii Xyl3A (GH3), had the highest levels of sugar release on oat spelt xylan, were in the top 10% of all genes transcribed by C. bescii, and were highly induced on xylan compared to cellulose. This indicates that a minimal set of enzymes are used to drive xylan degradation in the genus Caldicellulosiruptor, complemented by hemicellulolytic inventories that are tuned to specific forms of hemicellulose in available plant biomasses. To this point, synergism studies revealed that the pairing of specific GH family proteins (GH3, -11, and -39) with C. bescii GH10 proteins released more sugar in vitro than mixtures containing five different GH10 proteins. Overall, this work demonstrates the essential requirements for Caldicellulosiruptor to degrade various forms of xylan and the differences in species genomic inventories that are tuned for survival in unique biotopes with variable lignocellulosic substrates. IMPORTANCE Microbial deconstruction of lignocellulose for the production of biofuels and chemicals requires the hydrolysis of heterogeneous hemicelluloses to access the microcrystalline cellulose portion. This work extends previous in vivo and in vitro efforts to characterize hemicellulose utilization by integrating genomic reconstruction, transcriptomic data, operon structures, and biochemical characteristics of key enzymes to understand the deployment and functionality of hemicellulases by the extreme thermophile Caldicellulosiruptor bescii. Furthermore, comparative genomics of the genus revealed both conserved and divergent mechanisms for hemicellulose utilization across the 15 sequenced species, thereby paving the way to connecting functional enzyme characterization with metabolic engineering efforts to enhance lignocellulose conversion.}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Crosby, James R. and Laemthong, Tunyaboon and Bing, Ryan G. and Zhang, Ke and Tanwee, Tania N. N. and Lipscomb, Gina L. and Rodionov, Dmitry A. and Zhang, Ying and Adams, Michael W. W. and Kelly, Robert M.}, year={2022}, month={Oct} }
 @article{laemthong_bing_crosby_adams_kelly_2022, title={Engineering Caldicellulosiruptor bescii with Surface Layer Homology Domain-Linked Glycoside Hydrolases Improves Plant Biomass Solubilization}, volume={9}, ISSN={["1098-5336"]}, DOI={10.1128/aem.01274-22}, abstractNote={Caldicellulosiruptor species hold promise as microorganisms that can solubilize the carbohydrate portion of lignocellulose and subsequently convert fermentable sugars into bio-based chemicals and fuels. Members of the genus have surface layer (S-layer) homology domain-associated glycoside hydrolases (SLH-GHs) that mediate attachment to biomass as well as hydrolysis of carbohydrates. Caldicellulosiruptor bescii , the most studied member of the genus, has only one SLH-GH.}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Laemthong, Tunyaboon and Bing, Ryan G. and Crosby, James R. and Adams, Michael W. W. and Kelly, Robert M.}, year={2022}, month={Sep} }
 @article{rodionov_rodionova_rodionov_arzamasov_zhang_rubinstein_tanwee_bing_crosby_nookaew_et al._2021, title={Genome-Scale Metabolic Model of
            Caldicellulosiruptor bescii
            Reveals Optimal Metabolic Engineering Strategies for Bio-based Chemical Production}, volume={6}, ISSN={2379-5077}, url={http://dx.doi.org/10.1128/msystems.01351-20}, DOI={10.1128/mSystems.01351-20}, abstractNote={The extremely thermophilic cellulolytic bacterium, Caldicellulosiruptor bescii , degrades plant biomass at high temperatures without any pretreatments and can serve as a strategic platform for industrial applications. The metabolic engineering of C. bescii , however, faces potential bottlenecks in bio-based chemical productions.}, number={3}, journal={mSystems}, publisher={American Society for Microbiology}, author={Rodionov, Dmitry A. and Rodionova, Irina A. and Rodionov, Vladimir A. and Arzamasov, Aleksandr A. and Zhang, Ke and Rubinstein, Gabriel M. and Tanwee, Tania N. N. and Bing, Ryan G. and Crosby, James R. and Nookaew, Intawat and et al.}, editor={Summers, Zarath M.Editor}, year={2021}, month={Jun} }
 @article{bing_sulis_wang_adams_kelly_2021, title={Thermophilic microbial deconstruction and conversion of natural and transgenic lignocellulose}, volume={13}, ISSN={1758-2229 1758-2229}, url={http://dx.doi.org/10.1111/1758-2229.12943}, DOI={10.1111/1758-2229.12943}, abstractNote={The potential to convert renewable plant biomasses into fuels and chemicals by microbial processes presents an attractive, less environmentally intense alternative to conventional routes based on fossil fuels. This would best be done with microbes that natively deconstruct lignocellulose and concomitantly form industrially relevant products, but these two physiological and metabolic features are rarely and simultaneously observed in nature. Genetic modification of both plant feedstocks and microbes can be used to increase lignocellulose deconstruction capability and generate industrially relevant products. Separate efforts on plants and microbes are ongoing, but these studies lack a focus on optimal, complementary combinations of these disparate biological systems to obtain a convergent technology. Improving genetic tools for plants have given rise to the generation of low-lignin lines that are more readily solubilized by microorganisms. Most focus on the microbiological front has involved thermophilic bacteria from the genera Caldicellulosiruptor and Clostridium, given their capacity to degrade lignocellulose and to form bio-products through metabolic engineering strategies enabled by ever-improving molecular genetics tools. Bioengineering plant properties to better fit the deconstruction capabilities of candidate consolidated bioprocessing microorganisms has potential to achieve the efficient lignocellulose deconstruction needed for industrial relevance.}, number={3}, journal={Environmental Microbiology Reports}, publisher={Wiley}, author={Bing, Ryan G. and Sulis, Daniel B. and Wang, Jack P. and Adams, Michael W. W. and Kelly, Robert M.}, year={2021}, month={Mar}, pages={272–293} }
 @article{straub_bing_otten_keller_zeldes_adams_kelly_2020, title={Metabolically engineeredCaldicellulosiruptor besciias a platform for producing acetone and hydrogen from lignocellulose}, volume={117}, ISSN={["1097-0290"]}, DOI={10.1002/bit.27529}, abstractNote={The production of volatile industrial chemicals utilizing metabolically engineered extreme thermophiles offers the potential for processes with simultaneous fermentation and product separation. An excellent target chemical for such a process is acetone (Tb = 56°C), ideally produced from lignocellulosic biomass. Caldicellulosiruptor bescii (Topt 78°C), an extremely thermophilic fermentative bacterium naturally capable of deconstructing and fermenting lignocellulose, was metabolically engineered to produce acetone. When the acetone pathway construct was integrated into a parent strain containing the bifunctional alcohol dehydrogenase from Clostridium thermocellum, acetone was produced at 9.1 mM (0.53 g/L), in addition to minimal ethanol 3.3 mM (0.15 g/L), along with net acetate consumption. This demonstrates that C. bescii can be engineered with balanced pathways in which renewable carbohydrate sources are converted to useful metabolites, primarily acetone and H2 , without net production of its native fermentation products, acetate and lactate.}, number={12}, journal={BIOTECHNOLOGY AND BIOENGINEERING}, author={Straub, Christopher T. and Bing, Ryan G. and Otten, Jonathan K. and Keller, Lisa M. and Zeldes, Benjamin M. and Adams, Michael W. W. and Kelly, Robert M.}, year={2020}, month={Dec}, pages={3799–3808} }
 @article{straub_bing_wang_chiang_adams_kelly_2020, title={Use of the lignocellulose-degrading bacterium Caldicellulosiruptor bescii to assess recalcitrance and conversion of wild-type and transgenic poplar}, volume={13}, ISSN={["1754-6834"]}, url={http://europepmc.org/abstract/med/32180826}, DOI={10.1186/s13068-020-01675-2}, abstractNote={Biological conversion of lignocellulosic biomass is significantly hindered by feedstock recalcitrance, which is typically assessed through an enzymatic digestion assay, often preceded by a thermal and/or chemical pretreatment. Here, we assay 17 lines of unpretreated transgenic black cottonwood (Populus trichocarpa) utilizing a lignocellulose-degrading, metabolically engineered bacterium, Caldicellulosiruptor bescii. The poplar lines were assessed by incubation with an engineered C. bescii strain that solubilized and converted the hexose and pentose carbohydrates to ethanol and acetate. The resulting fermentation titer and biomass solubilization were then utilized as a measure of biomass recalcitrance and compared to data previously reported on the transgenic poplar samples.Of the 17 transgenic poplar lines examined with C. bescii, a wide variation in solubilization and fermentation titer was observed. While the wild type poplar control demonstrated relatively high recalcitrance with a total solubilization of only 20% and a fermentation titer of 7.3 mM, the transgenic lines resulted in solubilization ranging from 15 to 79% and fermentation titers from 6.8 to 29.6 mM. Additionally, a strong inverse correlation (R2 = 0.8) between conversion efficiency and lignin content was observed with lower lignin samples more easily converted and solubilized by C. bescii.Feedstock recalcitrance can be significantly reduced with transgenic plants, but finding the correct modification may require a large sample set to identify the most advantageous genetic modifications for the feedstock. Utilizing C. bescii as a screening assay for recalcitrance, poplar lines with down-regulation of coumarate 3-hydroxylase 3 (C3H3) resulted in the highest degrees of solubilization and conversion by C. bescii. One such line, with a growth phenotype similar to the wild-type, generated more than three times the fermentation products of the wild-type poplar control, suggesting that excellent digestibility can be achieved without compromising fitness of the tree.}, number={1}, journal={BIOTECHNOLOGY FOR BIOFUELS}, author={Straub, Christopher T. and Bing, Ryan G. and Wang, Jack P. and Chiang, Vincent L. and Adams, Michael W. W. and Kelly, Robert M.}, year={2020}, month={Mar} }