Glycerol serves as a versatile C3 platform chemical with broad applications spanning pharmaceuticals, personal care, food, cosmetics, and as a renewable feedstock for value-added chemicals, fuels, and materials. Methanol, a promising substrate derivable from CO2, biomass, and biogas offers a sustainable route for glycerol production. Herein, we employed the thermophilic methylotroph Bacillus methanolicus as a microbial cell factory for methanol bioconversion to glycerol. Given the poor thermolability of conventional mesophilic enzymes in the glycerol synthesis pathway at elevated temperatures, we identified and introduced thermostable glycerol 3-phosphate dehydrogenase and glycerol 3-phosphate phosphatase. These enzymes exhibited up to 185-fold longer half-life at 50 °C than their Saccharomyces cerevisiae counterparts. To precisely regulate the heterologous pathway, we engineered a synthetic promoter library comprising 100 variants, derived from the strong constitutive promoter of the 3-hexulose-6-phosphate synthase gene, which spanned five orders of magnitude in strength. By leveraging the endogenous, methylotrophy-essential plasmid pBM19 as a stable expression vector, we optimized the expression of the thermostable enzymes using selected promoters. The final engineered strain, which is independent of antibiotics and devoid of exogenous plasmids, achieved glycerol titers of 0.62 g/L in shake flasks and 8.9 g/L in bioreactors using methanol as the sole carbon source. This work constitutes the first report of glycerol production from methanol and establishes a foundational platform for synthesizing chemicals from methanol via glycerol as a key intermediate.

The electrochemical oxidation of lignocellulose and plastic waste has been considered a clean and reliable strategy to produce feedstocks for various chemicals and fuels. In this study, we tackle the challenging selective oxidation of various lignocellulose and mixed biodegradable and bio-nondegradable plastics by targeting the oxidative cleavage of the specific C(OH)-C moiety. A monometallic Ni(O)O-H electrocatalyst was used for valorization of cellulose-based biomass, a series of lignin-based model complexes, lignin-derived secondary alcohols (KA oil), and mixed plastic waste based on the catalyst's O-H bond dissociation free energy. The catalyst performs remarkably well to selectively oxidize cellulose and lignin-based model complexes like HMF and PED with excellent yield at a higher current density of 100 mA cm-2. Mechanical insights into this reaction were obtained by in situ transmitted light spectroscopy and Raman measurements. The catalyst was also able to oxidize KA oil to adipic acid with 54% yield at a constant current electrolysis of 20 mA cm-2. Furthermore, plastic waste precursors having a C(OH)-C bond were selectively oxidized using this catalyst, which was further expanded to mixed plastic waste upgradation resulting in the generation of formate and acetate with faradaic efficiencies of 66% and 74%, respectively, and 100% yield in terephthalic acid accompanied by the co-production of hydrogen.

Abstract Amides, which contain both oxygen and nitrogen, are present in many potential feedstocks for renewable fuels. There is a consequent need to study the hydrodenitrogenation (HDN) and hydrodeoxygenation (HDO) of amides. This work studies the HDN and HDO of hexadecanamide with sulfided NiMo/ $$\gamma $$ - $$\hbox {Al}_2\hbox {O}_3$$ and NiMo/ $$\hbox {TiO}_2$$ catalysts. The experiments are conducted in a batch reactor, with decalin as a solvent. Hexadecanamide is found to easily undergo either dehydration into hexadecanenitrile or deammonization into palmitic acid. Hydrotreating of hexadecanamide consequently occurs either through an initial HDO step (dehydration) into hexadecanonitrile, followed by reduction and HDN of the resulting hexadecylamine, or through an initial HDN step (deammonization) followed by HDO of the resulting palmitic acid. On both NiMo/ $$\gamma $$ - $$\hbox {Al}_2\hbox {O}_3$$ and NiMo/ $$\hbox {TiO}_2$$ , HDN of the amide is slower than HDO. The secondary amine, dihexadecylamine, is a major intermediate, formed through condensation reactions between hexadecylamine and palmitic acid or by the self-condensation of hexadecylamine. Thus, after the initial dehydration or deammonization step, hydrotreating of the primary amide follows the pathways associated with the HDN of primary amines and the HDO of primary carboxylic acids. NiMo/ $$\hbox {TiO}_2$$ is a more active amide hydrotreating catalyst than NiMo/ $$\gamma $$ - $$\hbox {Al}_2\hbox {O}_3$$ . This is attributed to $$\hbox {TiO}_2$$ catalyzing the initial dehydration (HDO) step, as well as to more complete sulfidation of Mo and the better incorporation of the Ni promoter in the $$\hbox {MoS}_2$$ phase on $$\hbox {TiO}_2$$ .

Selectively converting lignin, a renewable and abundant biomass resource, into high-value-added chemicals via hydrodeoxygenation (HDO) is a promising strategy for addressing global energy shortages and advancing sustainable practices in the agricultural and forestry industries. However, the catalytic performance of cobalt on carbon-based catalysts, particularly those prepared through pyrolysis, is often significantly hindered by the formation of carbon-coated structures that limit their activity. In this study, we developed a novel bifunctional catalyst, the redox catalyst, O-4Co/TA-600, featuring highly exposed Co/CoOx sites specifically tailored for the HDO of lignin and its model compounds. Experimental results demonstrated that tetracycloacetate-based O-4Co/TA-600 effectively cleaved various ether bonds and removed alcohol hydroxyl groups during the HDO process, achieving high alkane selectivity. The exceptional catalytic performance of O-4Co/TA-600 was attributed to the highly accessible active Co/CoOx sites and the synergistic effects between metallic Co and the acidic sites provided by CoOx, which enhanced substrate adsorption and facilitated active hydrogen (H*) generation. The catalyst retained its superior HDO activity toward diphenyl ether (DPE) after 11 reuse cycles, showcasing its excellent stability and reusability. When applied to enzymatic lignin and commercial calcium lignosulfonate, the catalyst achieves alkane selectivities of 97.6 and 92.6%, respectively. This study demonstrates a sustainable and efficient strategy for converting lignin into a feedstock for valuable chemicals and renewable fuels, thereby promoting biomass utilization in green industrial processes.

Transition from fossil fuels to renewable energy is critical to achieve climate protection objectives. Fuel production using renewable energy and carbon dioxide is an essential part of reducing fossil dependence and reducing overall carbon footprint. One of the highest value applications in current markets is the production of liquid transportation fuels like sustainable aviation fuels (SAF) and low (fossil) carbon diesel fuel through carbon capture and utilization pathways. Liquid hydrocarbon fuels only achieve decarbonization goals if they replace fossil fuels and are produced from sustainable carbon resources.With the support of EERE BETO contract EE0008917, OxEon designed and fabricated a system to produce high value, energy dense, liquid transportation fuels from biogas. The technology has completed initial subsystem verification, and the fully integrated pre-pilot system demonstration is scheduled to start operation in Q1 2025. Anaerobic digester gas is first converted to synthesis gas (CO + H2, syngas), the bio-CO2 through CO2-steam co-electrolysis in a SOEC system and the bio-CH4 through a low energy, non-thermal plasma reformer.The combined syngas streams are compressed and supplied to a modular fixed bed FT reactor for production of liquid hydrocarbons, which serve as the feedstock for SAF, renewable diesel, and other qualified marine fuels. The combination of technologies offers several advantages: the yield of biofuel nearly doubles by using bio-CO2 compared to bio-CH4 alone. The FT reactor cooling system generates steam needed in the SOEC, which lowers the effective operating voltage (including phase change energy) from ~1.5 V/cell to < 1.3 V/cell, and oxygen by-product from the SOEC is used in the autothermal reformer, as is some of the FT produced water. The resulting product fuel is all bio-carbon. The system concept block diagram and the pre-pilot demonstration hardware are shown in Figure 1.The pre-pilot demonstration system was designed and fabricated by OxEon Energy and installed at Wasatch Resource Recovery (WRR). WRR is a public-private partnership producing renewable natural gas (RNG) from food waste. The OxEon pre-pilot system, converting anaerobic digester gas CO2 and CH4 to FT hydrocarbons with a production rate of 6-8 gallons/day is in the commissioning phase. Operation is scheduled to begin in Q1 2025. The system will demonstrate a cumulative time on stream of 500-1,000 hours, producing 100-250 gallons of FT synthetic crude. Subsystem verification of the SOEC, plasma reformer, and FT technologies were conducted to demonstrate key performance targets. In addition to the verification run specifically for this pre-pilot demonstration, OxEon has operated each subsystem technology in thousands of hours of validation testing. A current program sponsored by the Naval Research Laboratory (NRL), includes scope to upgrade FT produced hydrocarbons to MIL-SPEC compliant JP-5 fuel.There is an emerging market for FT technology aimed at a variety of small, distributed resources including biomass, biogas, and cement kiln CO2, augmented by renewable and nuclear-powered CO2 co-electrolysis to increase the sustainable fuel capacity. FT technology to convert these fuel sources to liquid fuels would require smaller systems that can be transported to the site versus site-built plants. Biomass/biogas has previously been an impractical feedstock for FT technology due to shipping logistics to meet required economies of scale. The challenge in developing these resources is producing a small-scale plant at the same cost per bbl/day capacity as large plants. To accomplish this task, OxEon Energy developed a system that uses larger diameter reactor tubes with a heat transfer insert to manage thermal control of the system. OxEon’s FT design requires fewer reactor tubes than the traditional fixed-bed industry design and uses standard pipe sizes for reduced reactor fabrication costs. These modular systems are designed for a 10-15 bbl/day production increment enabling 100 bbl/day modules.OxEon has demonstrated FT operation with a variety of syngas sources including syngas produced via natural gas reformation, reverse water gas shift (RWGS) of CO2, and co-electrolysis of steam and CO2. Extensive performance mapping with the modular FT reactor design has also informed catalyst characteristics such as pore size, support shape, and precious metal promoter loading to allow for targeted FT product production. OxEon’s FT systems have been built and operated for both government and private customers ranging in production from 100 mL/day to 2 bpd. Figure 1

Carbon dioxide reduction reaction (CO₂RR) offers significant potential for closing the carbon loop by converting CO₂ into value-added feedstocks for industries or renewable fuels. Among the diverse categories of CO₂RR electrocatalysts, single-atom catalysts (SACs), in particular, metal-nitrogen-doped carbon (M-N-C) catalysts are emerging as promising candidates, owing to their optimal atom utilization efficiency, well-defined active sites, relatively uniform active centers. Up to date, M-N-C catalysts have demonstrated excellent performance in electrochemical CO2-to-CO conversion, but only within very narrow potential windows. Such limited working potentials will negatively affect the real-world industrial applications with complex operation variations, which may introduce unwanted byproducts (i.g. H2).Herein, we successfully synthesized a high-efficient Fe-N-C electrocatalysts for CO2RR, achieving near 100% CO conversion efficiency across a broaden potential range. In this work, zeolitic imidazolate frameworks (ZIF-8) were utilized as a template to create a porous structure, providing a high surface area and well-distributed pores, while the mechanical collisions from ball milling process can enhance the interaction of Fe source with the support materials. As a result, the high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images show that the synthesized catalyst possesses atomically dispersed Fe single atom sites, which are uniformly distributed and anchored within a nitrogen-doped carbon matrix. The X-ray photoelectron spectroscopy analysis further corroborates this, showing characteristic peaks corresponding to Fe-N x coordination bonds, indicative of strong interactions between the Fe atoms and the surrounding nitrogen-doped carbon framework.The as-prepared Fe-N-C catalysts were implemented in CO2RR, achieving an exceptionally high faradaic efficiency (FE) for CO production, exceeding 99% across a wide potential range from -0.3 V to -1.2 V vs. RHE. In addition, the partial current density of CO at -1.2 V vs. RHE in a flow cell reaches up to 27.25 mA/cm2. Stability studies reveal that our catalysts exhibit consistent CO2RR performance in 5 hours, maintaining the CO selectivity with near 100%. XANES and theoretical studies will reveal the inherent electronic structure for great CO2RR performance with near-unity CO conversion. The details will be shown in the presentation. This work highlights the potential of Fe single-atom catalysts derived from ZIF-8 precursors as a scalable and robust solution for CO₂ electroreduction.

CO2 is a potential feedstock for carbon-based fuels or materials, but is only available in dilute streams. Integrated processes for CO2 capture and conversion directly valorize the CO2 captured by sorbent materials, skipping the energetically expensive sorbent regeneration step. Amines are the most heavily studied liquid-phase sorbent materials for CO2 capture from dilute streams. Amines react with CO2 in a 2:1 ratio to form the corresponding ammonium carbamate. Ammonium carbamate [NH4]-[H2NCO2] was tested as the substrate using the highly selective and robust CO2-to-formate reduction electrocatalyst [(tBuPOCOP)-Ir-(H)-(NCCH3)2], where (tBuPOCOP) is the tridentate pincer ligand 2,6-bis-(ditert-butyl-phosphonito). When ammonium carbamate was used as the substrate instead of CO2, only hydrogen was produced. An equivalent electrolysis with ammonium hexafluorophosphate with CO2 also resulted in primarily hydrogen. Methyl carbamate and urea were also tested as substrates as proxies for carbamate that do not contain an equivalent of ammonium, and there was also negligible reduction to carbon-based products. These results indicate that the loss of selectivity observed for amine-captured CO2, or ammonium carbamate, is likely due to the generation of the acidic ammonium equivalent as well as the greater challenge of reducing carbamate compared to CO2. This study illustrates that catalysts with high selectivity for concentrated CO2 can favor hydrogen evolution and loss of carbon-based products when amine-captured CO2 is used instead.

Abstract Directional conversion of organic matter in coals has been a promising protocol for transforming coals into high‐value chemicals, high‐performance carbon materials, and high‐density liquid fuels. Low‐rank coals (LRCs) exhibit overwhelming advantages as feedstocks for liquid fuels and valuable chemicals, due to their higher H/C atom ratio, volatile, and contents of oxygen‐functional groups. Organic matter in LRCs is rich in condensed aromatic rings, which are connected by various types of C─C/〉C─O bridge bonds, some alkyl side chains and heteroatom‐containing groups. How to effectively cut the large molecules into small organic molecules with high value‐added chemicals? This is the core scientific problem in the coal conversion technologies. Catalytic hydroconversion (CHC) is one of the effective methods, containing catalytic hydrocracking/hydrorefining, for converting coals to clean liquid fuels. Catalyst plays an important role in activating hydrogen, promoting directed hydroconversion, and removing heteroatoms, which directly determines the reaction system and product quality. In this perspective, we intend to give readers a survey of the research advances in the catalytic hydroconversion of organic matter in low‐rank coals and transference of active hydrogen. Finally, some perspectives are prospected for future developments and selective CHC of organic matter in coals and high value‐added clean utilization of coals.

Lignocellulosic biomass is a feedstock for fuels and chemicals that does not compete with food resources and has less contaminants than refuse-derived biomass feedstocks. To convert lignocellulosics to biofuels or value-added products, multiple processing steps are typically necessary. One method of producing biofuels from lignocellulosic biomass utilizes a deacetylation and mechanical refining pretreatment and an enzymatic hydrolysis reaction to produce fermentable sugars from cellulose and hemicellulose. The rheological properties of biomass, such as yield stress and plastic viscosity, change during enzymatic hydrolysis and alter the energy requirements for pumping and mixing, an important consideration for the design of processing equipment. The dynamic changes in rheological properties that occur in a corn stover feedstock undergoing enzymatic hydrolysis are characterized in this work, and the influence on pressure losses in piping systems is estimated. Two rheometer geometries were fabricated with stereolithography 3D printing to reduce wall slip and sample ejection. The slurries have complex rheological behaviors that include shear-thinning behavior. Shear stress ramps were performed on samples at 20 and 50 °C using the custom geometries, and the Herschel–Bulkley model was fit to the data. The dynamic nature of the rheological properties is correlated with changes in the average fiber length at various extents of reaction, and the influence of solids concentration on the observed rheology and piping pressure losses is discussed.

Lignin is a plentiful natural aromatic resource, offering potential as a feedstock for alternative fuels and chemicals.1 Dye-sensitized photoelectrochemical cells (DSPEC) have been used to C-C bond cleavage of lignin to earn valuable aromatic compounds under mild conditions, low applied bias, and room temperature.2 An oxoammonium, generated through the oxidation of an aminoxyl radical mediator, facilitates selective reactions by oxidizing benzylic alcohol or aliphatic alcohol groups following C-C bond cleavage, lowering the bond dissociation energy.3 Activation of the oxoammonium is crucial for efficient catalytic reaction, achieved through hole transfer from the oxidized dye under illumination. The effectiveness is measured by photocurrent, reflecting the oxoammonium generation driving force, which is related to the Gibbs free energy between the aminoxyl radical mediator and the HOMO energy level of the sensitizer. Therefore, elucidating the impact of organic sensitizer with D-π-A structures on oxoammonium generation driving force is vital for lignin oxidative cleavage reaction. We adjusted the HOMO to achieve close to zero, negative, and positive oxoammonium generation driving forces by modifying triphenylamine based donor structure with substituents such as -H, -OCH3, and -carbazole. The resulting photocurrent density, interfacial activity, and the yield of the lignin degradation products were proportional to the driving force, indicating the importance of the sensitizer design in controlling the oxidative cleavage reaction. Figure 1

Catalytic methane decomposition (CMD) offers an eco-friendly method to produce COx-free hydrogen and solid carbon. An innovative approach for catalyst regeneration involves utilizing CO2 as a reactant to produce CO via the Reverse Boudouard Reaction, which serves as a valuable feedstock for various chemicals and fuels. This study aims to investigate the role and interaction of Ni nanoparticles on cerium oxide support by comparing two catalysts: one synthesized via the conventional impregnation method (Imp) and the other through solution combustion synthesis (SCS). Both catalysts containing the same Ni loading of 5 wt% and were tested under identical conditions. Comprehensive characterization techniques, including XRD, H2 and O2 TPR, TEM, SEM, XPS, and Raman spectroscopy, were employed to elucidate the observed performances. The SCS catalyst resulted in smaller Ni nanoparticles with stronger metal-support interaction. Observations revealed both tip and base carbon growth for the SCS catalyst, whereas the Imp catalyst predominantly characterized by tip growth. For the SCS catalyst, carbon nanofibers and nanotubes were observed, and both appeared active in carbon CO2 gasification. For the Imp catalyst, more crystalline carbon is observed. The amount of carbon produced was much more and managed to cover the entire catalyst. For SCS carbon coverage was partial. Two rates of CO2 gasification were observed depending on the extent of carbon coverage. Across all tested temperatures and space velocities, the catalyst prepared by impregnation exhibited higher reaction rates. The Imp catalyst demonstrated 15 % higher CMD and 29 % more generated carbon than SCS. This work demonstrated the critical role of key factors influencing the catalytic performance of this cyclic process. This includes the Ni nanoparticle size and distribution, the metal-support interaction's strength, and the graphitic carbon's nature.

Herein, a mixture of real polypropylene (PP) waste was pyrolyzed with a HZSM-11 catalyst as a potential method to recover light hydrocarbons (C ≤ 12 ), the potential feedstock for value-added chemicals and fuels, from polyolefin plastic waste. Using the HZSM-11 in the PP waste mixture pyrolysis noticeably improved the yield of gas pyrolysate and oil in compensation for the yield of wax (i.e. hydrocarbons of C &gt; 20 ) and solid residue particularly at a higher temperature. In addition, the selectivity of C 3 –C 12 in the PP-waste mixture-derived pyrolysate was markedly increased by the HZSM-11. The highest yield of light hydrocarbons was ≈40 wt% (per mass of the feedstock) achieved at 700 °C with the HZSM-11 catalyst. Despite 7.9 wt% coke deposition on the HZSM-11 after its use in the pyrolysis of the PP waste mixture, the catalyst could be reusable for at least three times after regeneration. The experimental results demonstrate that HZSM-11 has the potential for being a promising catalyst to valorize polyolefin waste into value-added chemicals.

To reduce emissions from combustion of fossil fuels, sustainable aviation fuels (SAFs) have the potential to decarbonize the aviation sector. Redirecting wastes from conventional waste management practices and using them as cost-effective feedstocks for low-carbon fuels can reduce emissions from both waste disposal and fuel combustion. One approach is to upgrade wet wastes to SAF precursors, such as volatile fatty acids (VFAs). In this study, novel membrane-assisted arrested methanogenesis was developed to convert high-strength wastewater to VFAs. Based on experimental results of VFA production, techno-economic and life-cycle analyses were conducted to estimate the potential economic and environmental benefits of SAF production from high-strength wastewater via VFAs. By evaluating three proposed scenarios for VFA production, a minimum production cost of VFA is achieved at $0.60/kg VFA at a wastewater flow rate of 1100 MT/d. For the corresponding VFA-derived SAF, the estimated minimum fuel selling price is $4.64/gasoline gallon equivalent. The life-cycle analysis shows that up to a 71% reduction in greenhouse gas emissions can be achieved relative to its fossil-counterpart along with lower water and fossil-fuel consumption.

We report here on the reductive rearrangement of biomass-derived furfural to cyclopentanone, a promising non-fossil feedstock for fuels and chemicals. An underreported aspect of this reaction is the inevitable formation of heavy byproducts. To mitigate its formation, process condition such as, solvent, catalyst, temperature, acidity, and feed concentration were varied to unravel the chemistry and improve the reaction performance. Water medium was confirmed to play a crucial role, as organic solvents were unable to deliver cyclopentanone or heavy by products. Copper-based catalyst showed the highest selectivity for ring-rearrangement, reaching 50 mol % under the conditions investigated. The main factor influencing the yields of cyclopentanone (CPO), and promote oligomer formation, are the feed concentration and the pH, as high feed concentrations and high acidity facilitate the self-polymerization of furfuryl alcohol (FALC). This was confirmed by dedicated experiments using FALC and the hydroxypentenone intermediate as feed. The concentration challenge could be mitigated by slowly dosing the feed, which increased the desired product yields by 4-12 mol %. Nevertheless, most oligomers appeared to fall in the range of common liquid fuels and could be converted to diesel by hydrodeoxygenation.

Exploration of hydrothermal liquefaction of multiple algae to improve bio-crude quality and carbohydrate utilization

Photocatalytic conversion of CO2 into fuel feed stocks is a promising method for sustainable fuel production. A highly attractive class of materials, inorganic-core@metal-organic-framework heterogeneous catalysts, boasts a significant increase in catalytic performance when compared to the individual materials. However, due to the ever-expanding chemical space of inorganic-core catalysts and metal-organic frameworks (MOFs), identification of these optimal heterojunctions is difficult without appropriate computational screening. In this work, a novel high-throughput screening method of nano-hybrid photocatalysts is presented by screening 65 784 inorganic-core materials and 20 375 MOF-shells for their ability to reduce CO2 based on their synthesizability, aqueous stability, visible light absorption, and electronic structure; the passing materials were then paired based on their electronic structure to create novel heterojunctions. The results showed 58 suitable inorganic-core materials and 204 suitable MOFs ranging from never-before-synthesized catalysts to catalysts that have been overlooked for their photocatalytic ability. These materials lay a new foundation of photocatalysts that have passed theoretical requirements and can significantly increase the rate of catalyst discovery.

The rapid rise in global plastic production in recent decades has resulted in the massive generation of plastic waste. Over 75% of the plastic waste generated in the United States was sent to landfills, with a meager 8.7% recycled. Plastics are valuable feedstocks for platform chemicals and fuels. Chemical upcycling of waste high-density polyethylene (HDPE) is gaining more attention as a potentially feasible and environmentally friendly plastic waste management technology. Conventional pyrolysis (CPY) and thermal oxo-degradation (TOD) are two chemical upcycling technologies actively researched for decomposing waste HDPE into valuable chemicals and fuels. However, there are few studies on the techno-economic analysis (TEA) and life cycle assessment (LCA) of these technologies for converting waste HDPE to valuable products. This study conducts a comparative TEA and LCA study of the thermochemical decomposition of waste HDPE to produce gaseous (ethylene and propylene) and liquid (naphtha, diesel, and wax) products by CPY and TOD. The study elucidates and compares the impact of hydrocracking longer chain hydrocarbons to produce more valuable products on the TEA and LCA. The TEA showed that the fixed capital investment could range from $32.5 million for TOD without hydrocracking to $244 million for CPY with hydrocracking scenarios. Annual revenues range from $28.1 million to $71.5 million in favor of scenarios with hydrocracking. However, the net present value ranges from $1.4 million to $265.8 million in favor of scenarios without hydrocracking. Sensitivity analysis showed that fixed capital cost, facility capacity, and product prices have the biggest impact on the process economics of the facilities, while utilities and waste transportation to refineries have the biggest impact on environmental impacts. The LCA showed that primary products from scenarios without hydrocracking can be more environmentally friendly than virgin products from petroleum processes. However, TOD and CPY with hydrocracking primary products have more emissions than those of virgin products.

Plant-based co-production of polyhydroxyalkanoates (PHAs) and seed oil has the potential to create a viable domestic source of feedstocks for renewable fuels and plastics. PHAs, a class of biodegradable polyesters, can replace conventional plastics in many applications while providing full degradation in all biologically active environments. Here we report the production of the PHA poly[(R)-3-hydroxybutyrate] (PHB) in the seed cytosol of the emerging bioenergy crop Camelina sativa engineered with a bacterial PHB biosynthetic pathway. Two approaches were used: cytosolic localization of all three enzymes of the PHB pathway in the seed, or localization of the first two enzymes of the pathway in the cytosol and anchoring of the third enzyme required for polymerization to the cytosolic face of the endoplasmic reticulum (ER). The ER-targeted approach was found to provide more stable polymer production with PHB levels up to 10.2% of the mature seed weight achieved in seeds with good viability. These results mark a significant step forward towards engineering lines for commercial use. Plant-based PHA production would enable a direct link between low-cost large-scale agricultural production of biodegradable polymers and seed oil with the global plastics and renewable fuels markets.

&#x0D; Resource scarcity and increasing climate change have brought attention to the need for sustainable and renewable resources. Biomass is an earth-rich material with great potential as a feedstock for alternative fuels and chemicals. In order to utilize biomass efficiently, such biopolymers must be depolymerized and converted into key structural units and/or target products, and biological or chemical catalysts are often used for fast and energy-efficient reactions. This paper presents recent advances in the catalytic conversion of biomass into biofuels and value-added products. Hydrodeoxygenation is an important and unique method for converting biomass and biomass-derived oxygenated chemicals into high value-added chemicals and fuels. However, the synthesis of catalysts with excellent hydrogenation and hydrodeoxygenation performance at the same time remains a great challenge.&#x0D;

Lignin is a promising feedstock for renewable fuels and chemicals due to its aromatic skeleton and natural abundance. Lignin can be converted to diverse aromatic monomers as well as dicarboxylic acids depending on the applied conversion technologies. Despite its great potential, its native and processing-induced heterogeneity and complexity limit the conversion efficiency and product selectivity. In this study, magnesium ferrite (MgFe2O4) nanoparticle–peracetic acid (PAA) has been investigated as an efficient catalyst–oxidant incorporation for catalytic oxidative depolymerization of lignin under mild conditions. Typically, the increase in processing severity can enhance the lignin conversion while it results in the further decomposition of aromatic compounds to dicarboxylic acids. However, in this study, the incorporation of MgFe2O4 nanoparticles and PAA not only enhanced the total product yield but also improved the selectivity of aromatic monomers. The oxidative depolymerization system using the catalyst–oxidant combination resulted in 46 wt % of total oil product with a 61% selectivity of aromatic monomers under mild temperature (90 °C). In addition, this combination catalyst showed relatively good cycling stability based on the total product yield after recycling five times via magnetic separation. Overall, MgFe2O4 nanoparticles play an important role as a co-catalyst with a PAA oxidant in the oxidative conversion of lignin with an enhanced conversion efficiency and recyclability, and it will facilitate the valorization of lignin in future bio-based fuels and chemicals.