One-pot Process Research Articles

Sulfur-modified polyurethane adhesives: Green synthesis process and disassembly-responsive characteristics

Polyurethane adhesives have been widely used in industrial production and daily life for their excellent properties. With the urgent need for social progress, the intelligent responsiveness of polyurethane adhesives has become more and more important. Here, we demonstrate a stimulus-responsive polyurethane adhesive. Starting from the structural design, sulfur (S8) is added into the polyurethane adhesive for the first time using the inverse vulcanized mechanism, and the controllable disassembly response of the polyurethane adhesive under the condition of thermal stimulation is realized. In addition, the stimulus response of the adhesive can also be activated through the permeation process of methoxide anion (CH3O−), and the rapid disassembly response property is displayed in the methanol solution of CH3ONa, to realize the recovery of the bonding substrate. Simultaneously, the implementation of the inverse vulcanized mechanism imparts the adhesive with a diminished water absorption swelling rate and heightened cross-link density. On the surface of the metal substrate, it shows excellent bonding properties, with a lap shear adhesion strength reaching 2.8 MPa. It is worth noting that the adhesive also exhibits excellent underwater durability. After 36 h of underwater soaking treatment, its adhesion can still be maintained at 2.4 MPa. This work reveals the mechanism of rapid disassembly of polyurethane adhesives at the molecular level. By density functional theory (DFT) calculation, it is found that the minimum bond energy of the S-S bond in a polyurethane adhesive system is 134 KJ·mol−1, and the disassembly response can be triggered by heating to 53.79℃. At the same time, the mechanism of the disassembly response induced by CH3O− is further analyzed using an electrostatic potential (ESP) diagram. This work utilizes sulfur (S8) and castor oil (CO) as raw materials, which can be sourced from industrial or agricultural by-products. It breaks away from traditional polyurethane adhesive preparation methods and offers a "green" strategy that can be synthesized through a solvent-free one-pot process, thus providing a new way of thinking about obtaining sustainable polymers from industrial and agricultural by-products.

Preparation of Pt and bamboo charcoal co-modified TiO2 for formaldehyde sensing at room temperature.

Anatase TiO2 has evolved into one of the most attractive materials for gas sensing owing to its strong oxidation activity and excellent sensing properties. In this study, we prepared Pt and bamboo charcoal co-modified nano-TiO2 using a one-pot hydrothermal process and applied it to detect formaldehyde. The successful incorporation of the precious metal Pt and bamboo charcoal onto TiO2 was confirmed by scanning electron microscope, transmission electron microscopy, energy dispersive spectrometer, X-ray diffraction and X-ray photoelectron spectroscopy. Detailed analysis revealed a homogeneous distribution of Pt nanoparticles and bamboo charcoal on the TiO2 surface, which significantly improved the surface area and facilitated gas adsorption. These modifiers significantly enhanced the response of TiO2 to formaldehyde, for instance, the response signal increased fourfold, while the response time decreased from 91 to 68 s. The sample with 0.5@Pt and 0.5@C bamboo charcoal performed the best, showcasing the synergistic effect of metal nanoparticles and carbonaceous materials on gas-sensing properties. Our work highlighted the potential of using biomass-derived carbon to enhance the detection of formaldehyde and demonstrated the importance of material characteristics in designing effective gas sensors.

Strategic design of magnetic ionic covalent organic frameworks incorporating amino acid ionic liquids for enhanced selectivity adsorption of benzimidazoles

Advancing the frontier of material design, our innovative magnetic ionic covalent organic framework (MiCOF) masterfully overcomes traditional barriers in selective adsorption, pioneering new functionalities and surface engineering techniques to effectively target and mitigate the impacts of benzimidazoles (BZDs). In previous studies, the idea of designing magnetic nanomaterials through theoretical screening of ionic liquids has been successfully proposed. This work proposed a theoretical and practical design for MiCOFs, aimed at providing a sensitive, selective, rapid, and straightforward method for analyzing trace substances in complex biological matrices. In a gentle one-pot process, the surface of Fe3O4 was coated with covalent organic frameworks (COFs) layer, followed by the modification with amino acid ionic liquid (AAIL) through covalent radical polymerization, facilitated by the abundant unsaturated vinyl groups present. This resulted in MiCOFs (Fe3O4@COF-AAIL) with a stable structure. Compared to unmodified Fe3O4@COF, Fe3O4@COF-AAIL exhibited excellent adsorption selectivity for BZDs. This enhanced selectivity is primarily due to the strong hydrogen bonds and π-π interactions between AAIL and BZDs, aligning well with COSMO-RS theoretical screening predictions. The development of magnetic dispersive solid-phase extraction (MDSPE) enabled rapid processing of BZDs in plasma with low matrix effects (0.9–1.3). This study not only validates a robust framework for the selective separation of trace contaminants in complex biological matrices but also advances the design and application of MiCOFs, setting a new paradigm in material science that could transform the design of novel materials for specific tasks.

Direct Defluorination and Amination of Polytetrafluoroethylene and Other Fluoropolymers by Lithium Alkylamides.

Polytetrafluoroethylene (PTFE) and, by extension, fluoropolymers are ubiquitous in science, life, and the environment as perfluoroalkyl pollutants (PFAS). In all cases, it is difficult to transform these materials due to their chemical inertness. Herein, we report a direct amination process of PTFE and some fluoropolymers such as polyvinylidene fluoride (PVDF) and Nafion by lithium alkylamide salts. Synthesizing these reactants extemporaneously between lithium metal and an aliphatic primary di- or triamine that also serves as a solvent leads to the rapid nucleophilic substitution of fluoride by an alkylamide moiety when in contact with the fluoropolymer. Moreover, lithium alkylamides dissolved in suitable solvents other than amines can react with fluoropolymers. This highly efficient one-pot process opens the way for further surface or bulk modification if needed, providing an easy, inexpensive, and fast experiment protocol on large scales.

Polysulfides for presulfiding of hydrogenation catalysts: synthesis, mechanism and applications

Presulfiding agents are widely used in oil refining and chemical industry, how to produce safe and efficient presulfiding agent by more environmentally friendly synthesis process are still problems to be solved. In this study, the organic polysulfide FSA-55 was synthesized by a practical one-pot process using isobutene and sulfur as raw materials and organic amine as a catalysts. The product components were analyzed and the possible catalytic reaction pathways in the thermal conversion of sulfides were elucidated. The amine catalysts showed a catalytic activities in inducing the ring opening of the cyclic molecular structure of sulfur at high temperature, thereby releasing the reactive sulfur radicals, which react with unsaturated double bonds through addition reactions. Different molecular structures of polysulfide were generated through molecular rearrangement and cyclization reactions. The suitability of the product as a presulfiding agent was investigated by analyzing the thermal properties and studying the presulfiding effect on hydrogenation catalysts. The polysulfide has a wide decomposition temperature range (100–260 °C), which can effectively avoid the occurrence of concentrated exothermic phenomena during presulfiding of hydrogenation catalysts. The presulfiding degree of the catalysts can reach 58.32%, which shows the great potential of oil processing as a presulfiding agent.

Multi-finished protective viscose textile via infrared assisted one-pot incorporation of Ce-organic framework

Antimicrobial and UV-blocking textiles (protective textiles) are quite required especially for outdoor workers and in hot weather countries. Herein, for the first time, under the effect of infrared radiation, the preparation of multi-finished viscose fabrics via the incorporation of metal organic framework-based on Cesium (Ce-MOF) is investigated. Ce-MOF using different ligands including 1,4-benzendicarboxylic acid (BDC), 1,2,4-benzene tricarboxylic acid (BDC-COOH) and 2-amino-1,4-dicarboxyic acid (BDC-NH2) were incorporated within viscose and cationic viscose (Q-viscose) fabrics in one-pot process. MOF uptake was significantly improved from 88.6 – 96.8 mg/g to 122.5 – 152.2 mg/g after the cationization process. Due to incorporation of Ce-MOF, viscose fabrics acquired creamy to yellowish color and became more thermally stable. Tensile strength was lowered by 8.9 – 17.4% for viscose and 17.1 – 20.3% for Q-viscose, after modification with Ce-MOFs. The estimated UV-protection factor (UPF) for Q-viscose fabrics was significantly increased to be 50.1– 88.1 after incorporation of Ce-BDC-COOH & Ce-BDC-NH2, achieving maximum UV protection. By comparing between Ce-BDC and Ce-BDC-COOH, the fabrics treated with Ce-BDC-NH2 showed the highest microbial protection against bacteria and fungus. After immobilization of Ce-MOF, the estimated inhibition zones were 11–14 mm & 15–18 mm against E. coli and 13–15 mm & 17–19 mm against C. albicans, for viscose and Q-viscose, respectively.

Synergy of atom doping and defect construction in marigold-like Zn3In2S6 for improved photocatalytic hydrogen production

Atom doping and defect construction are effective strategies to enhance the performance of photocatalysts. Herein, zirconium (Zr) doping and sulfur vacancies (Vs) are introduced on marigold-like Zn3In2S6 (Zr-ZIS-Vs) by controlling the amount of sulfur precursors and ZrCl4 via a one-pot hydrothermal process. Remarkably, the optimized Zr-ZIS-Vs catalyst exhibits excellent photocatalytic activity, giving a photocatalytic hydrogen evolution rate of 9.44 mmol g−1 h−1, which is 10.73, 4.39 and 2.37 times higher than pure Zn3In2S6 (ZIS, 0.88 mmol g−1 h−1), Zn3In2S6 with sulfur vacancies alone (ZIS-Vs, 2.15 mmol g−1 h−1), and Zn3In2S6 with Zr doping alone (Zr-ZIS, 3.98 mmol g−1 h−1). The apparent quantum efficiency (AQE) of Zr-ZIS-Vs achieves 27.15 % and 4.90 % at λ = 370 and 456 nm, respectively. Experimental results and theoretical simulations reveal the behavioral mechanisms of the deletion of S atoms and the tendency of Zr to replace In, indicating that the defective and reference strategies can narrow the band gap, provide abundant active sites, enhance the effective transport and separation of photogenerated carriers, and modulate the transfer of active sites to empirical site S atoms to achieve the synergistic thermodynamic and kinetic interactions, which effectively enhances the performance of photocatalytic hydrogen production.

Domino Conjugate Addition-1,4-Aryl Migration for the Synthesis of α,β-Difunctionalized Amides.

A domino difunctionalization of sulfonyl(acryl)imides to form β-substituted α-aryl amides is reported. This transformation involves a 1,4-addition followed by a polar Truce-Smiles rearrangement process, entropically driven by release of SO2. A wide range of carbon- and heteroatom-based nucleophiles and sulfonyl imides were employed, allowing rapid access to highly functionalized amides. In contrast to related reactions with a radical pathway, unbiased substrates could be employed. Despite the usual requirement of an electron-poor migrating moiety for the SNAr event, we herein report unique and unprecedented vinylogous migrations of electron-neutral arenes. Additionally, a one-pot process toward β-amido amides starting from acrylic acids has been developed.

N-heterocyclic carbene promoted one-pot synthesis of 1,2-diols and ɑ-Hydroxyketones from simple aldehydes

The α-hydroxyketones and 1,2-diols are versatile building blocks for the preparation of many natural and synthetic bioactive compounds. In this study, N-heterocyclic carbon (NHC) promoted coupling of several aldehydes with formaldehyde enabled the synthesis of 1,2-diols in moderate to high yields. The highly selective conversion of several aldehydes and formaldehyde into 1,2-diols and α-hydroxyketones was achieved in a one-pot two-step process via [BHMIm][OAc] as a key intermediate. In the first step, formaldehyde was quantitatively converted to [BHMIm][OAc] through the carbene addition. In the second step, 1,2-diol was produced through the intermediate-promoted aldol reaction. The results showed that benzaldehyde was capable to react with [BHMIm][OAc] efficiently, with a 54.1% yield of 1,2-diol after the 3-hour reaction at 85 °C. Among the tested benzaldehyde derivatives, the 4-nitrobenzaldehyde showed the highest yield of 1,2-diol (73.3%) under the optimized reaction conditions. Incorporation of an electron rich group on benzaldehyde promoted carbene regeneration. With 4-methoxybenzaldehyde as the substrate, the yield of α-hydroxyketone reached a maximum of 30.6%. Additionally, dihydroxyacetone derivatives were detected in the system. In situ NMR technique confirmed that it was generated from the further reaction of the carbene/1,2-diol complex with another aldehyde. Based on the results of NMR spectroscopy and mass spectrometry, a possible reaction pathway was also proposed.

Mesoporous silica-encapsulated nitrogen-doped fluorescent carbon dots modified polydopamine composites for monitoring non-steroidal anti-inflammatory drugs

A one-pot hydrothermal process incorporated nitrogen-doped fluorescent carbon dots (N-FCDs) into the pores of mesoporous silica (m-SiO2). Under weakly alkaline conditions, the m-SiO2/N-FCDs were further functionalized with dopamine to develop m-SiO2/N-FCDs modified polydopamine (m-SiO2/N-FCDs/PDA). The m-SiO2/N-FCDs/PDA exhibited emission at a wavelength of 520 nm (λexc. = 440 nm) and demonstrated excellent quenching efficiency in the presence of NSAIDs (aspirin, diclofenac, ketoprofen, naproxen, and ibuprofen) with a detection limit of 0.045 – 1.43 nM. Furthermore, the m-SiO2/N-FCDs/PDA was utilized to detect NSAIDs in tap and river water and pharmaceutical commercial tablets showing high recoveries of 90.96–100.41 % with RSD < 4.

Ultrahigh temperature ablation resistant HfB2-SiC composites: From liquid SiHfCB precursor synthesis to light weight bulk preparation and characterization

The current generation of ultrahigh temperature ceramic precursors typically encounters obstacles in achieving high ceramic yields (<40 wt.%) due to the challenges in integrating significant amounts of boron, which hampers their conversion into boride-based ultrahigh temperature ceramics. To tackle these challenges, a serious of pioneering liquid multi-component hafnium-containing ceramic SiHfCB precursors (with different Hf/Si ratios) have been developed. These novel precursors are featured with stable molecular structure and high ceramic yield which were successfully created through a novel one-pot polymerization process. They present in liquid form and their structure is characterized by C-C bonds forming its main chain with branched chains of O-Si-O, Si-O-Hf, Si-O-B, and B-O-Hf which have untapped advantages including uniform component dispersion, and excellent fluidity. The ceramic yield of SiHfCB precursor with Hf/Si of 0.2 is remarkably up to 68.6 wt.% at 1500 °C, and their Hf content exceeded 50 wt.%. Of particular interest, the pyrolyzed product HfB2-SiC nanopowders derived from the SiHfCB precursor with Hf/Si of 0.2, consist of nanopowders in the 40–60 nm range with a density of 5.23 g cm−3. Remarkably, this material demonstrates exceptional performance in ultrahigh temperature oxygen-containing environments at 2500 °C, showing near-zero ablation with a linear ablation rate of just 2.5 × 10−4 mm s−1. Post-ablation analysis of the microstructure reveals that the formation of a lava-like HfO2 and HfO2-SiO2 oxide layer effectively blocks oxygen penetration and provides excellent oxidation resistance. The innovative SiHfCB hafnium-containing ceramic precursor offers a groundbreaking solution for the preparation of lightweight ultrahigh-temperature ceramics. This development is poised to provide robust technical support for the use of ultrahigh temperature ceramics in non-ablative thermal protective systems, particularly in the construction of hypersonic vehicles, where ultrahigh temperature resilience is crucial.

Surface-engineered in-situ fibrillated thermoplastic polyurethane as toughening reinforcement for geopolymer-based mortar

Geopolymer composites often exhibit severe brittle failure when subjected to tensile and flexural loads, mainly owing to their inherently ceramic-like structure. Therefore, this study aims to overcome the previously mentioned weaknesses by introducing 2 wt% of surface-modified, in-situ fibrillated Co-PP (copolymer of polyethylene (PE) and polypropylene (PP))/thermoplastic polyurethane (TPU) blend to produce fiber-reinforced geopolymer mortars. The fiber-in-fiber Co-PP/TPU was first fabricated using spunbond, then functionalized using a mild, two-step, one-pot chemical surface modification process. A comprehensive and detailed study of the fibers' chemical structure, morphology, and mechanical properties has been conducted. As well as their impact on the geopolymer mortars' mechanical performances. Moreover, incorporating the modified fibers dramatically increased the flexural toughness and strength at failure of the composite, reaching up to 1600 % and 280 % compared to the control sample, respectively. Furthermore, the flexural modulus was improved by 2 folds. Additionally, the split tensile and compressive strength were improved by 84 % and 17 %, respectively. These findings and the SEM images of the fractured samples indicate the presence of several toughening mechanisms, associated with an improved matrix-fiber interface and an enhanced growth of geopolymer products around the fiber's surface.

One-pot Synthesis of High-capacity Sulfur Cathodes via In-situ Polymerization of a Porous Imine-based Polymer.

Lithium-ion batteries, essential for electronics and electric vehicles, predominantly use cathodes made from critical materials like cobalt. Sulfur-based cathodes, offering a high theoretical capacity of 1675mAhg-1 and environmental advantages due to sulfur's abundance and lower toxicity, present a more sustainable alternative. However, state-of-the-art sulfur-based electrodes do not reach the theoretical capacities, mainly because conventional electrode production relies on mixing of components into weakly coordinated slurries. Consequently, sulfur's mobility leads to battery degradation - an effect known as the "sulfur-shuttle". This study introduces a solution by developing a microporous, covalently-bonded, imine-based polymer network grown in-situ around sulfur particles on the current collector. The polymer network (i) enables selective transport of electrolyte and Li-ions through pores of defined size, and (ii) acts as a robust host to retain the active component of the electrode (sulfur species). The resulting cathode has superior rate performance from 0.1C (1360mAhg-1) to 3C (807mAhg-1). Demonstrating a high-performance, sustainable sulfur cathode produced via a simple one-pot process, our research underlines the potential of microporous polymers in addressing sulfur diffusion issues, paving the way for sulfur electrodes as viable alternatives to traditional metal-based cathodes.

Enantioselective Synthesis of Secondary Amines by Combining Oxidative Rearrangement and Biocatalysis in a One-Pot Process.

This contribution describes the development of chemoenzymatic one-pot processes, which combine an oxidative rearrangement and a biotransformation catalyzed by an imine reductase (IRED), for the synthesis of highly enantiomerically enriched secondary amines, such as an aryl-substituted pyrrolidine and a benzazepine. The benefits of this chemoenzymatic one-pot approach include high overall conversions (up to >99%), high enantiomeric excesses (up to >99% ee), and a straightforward synthetic approach toward secondary amines without the need to isolate the formed intermediate. For the initial chemical reaction, namely, the oxidative rearrangement, PhI(OAc)2 in methanol is used as a non-natural reagent, whereas the enzymatic step requires only stoichiometric amounts of d-glucose along with catalytic amounts of IRED, glucose dehydrogenase (GDH), and the cofactor NADPH. This methodology, demonstrating the compatibility of a "classic" organic synthesis using a non-natural, highly reactive reagent and a subsequent biocatalytic step, can be applied for different amines as substrates, thus making this concept a versatile tool in synthetic organic chemistry in general and for enantioselective synthesis of heterocyclic secondary amines in particular.

Enhanced the electrochemical performance of Ni-doped α-MnO2 prepared with one-pot process for supercapacitors

Poor capacitive behavior caused by low electronic conductivity and slow reaction kinetics is the main obstacle faced by the MnO2 electrode materials in current supercapacitors. Herein, the influence of Ni doping on the capacitive behavior of α-MnO2 synthesized by a low-cost and one-pot chemical coprecipitation method was investigated. During the doping process, the amount of Ni was increased from 0.05 mmol to 0.45 mmol in steps of 0.1 mmol. The structure and chemical composition of Ni-doped MnO2 (MnO2-Ni) were characterized by XRD, FTIR, SEM, EDS, and XPS. Comprehensive studies show that no change in the crystal phase structure of MnO2, while the decrease in the nanoparticle size and the increase in electronic conductivity by Ni doping, which improve the capacitive behavior of α-MnO2. With specific capacitance values increasing with increasing amounts of Ni up to a certain limit 0.25 mmol, the specific capacitance of 325.8 F/g was given by MnO2-Ni electrode at a current density of 0.5 A/g, which was nearly 1.72 times that of MnO2 electrode of 189.47 F/g. Moreover, the MnO2-Ni electrode showed excellent capacitance retention (112%) than the MnO2 electrode (109.5%) after 3000 cycles.

Ultrasound-Assisted Catalyst-free Synthesis of α,β -Unsaturated Amino Acid Esters and Unsaturated Amino Ketones

Introduction: Sonication has been introduced as a green and effective activation method for the selective monoamination of β-dicarbonyl compounds. The simple one-pot process resulted in different substituted β-amino-ɑ,β-unsaturated esters and ketones at room temperature with quantitative yields. Aqueous NH4OH was used as a safe and economical nitrogen source for pressurized NH3 gas. The process is considered green, accounting for not using any solvents and catalysts, besides some aqueous NH4OH-involved reactions using nontoxic water. A broad variety of useful synthetic intermediates, β- amino-ɑ,β-unsaturated esters and ketones have been prepared in short reaction time. Methods: Using this developed protocol, we were able to synthesize a series of structurally diverse β- amino-ɑ,β-unsaturated esters and unsaturated amino ketones. Results: The synthesis of target compounds was achieved in a truly green process with high atom economy and excellent yields in a catalyst-free one-pot system in an aqueous medium using simple, commercially available, inexpensive ammonium hydroxide as the source of the nitrogen. The high atom economy has been accompanied by the formation of a small amount of nontoxic waste, water. Conclusion: In conclusion, a simple, convenient, and high-yielding catalyst-free environmentally benign method was developed for the synthesis of unsaturated amino acid esters and unsaturated amino ketones.

Valorization of Furfural to Obtain High Value-Added Products with ZrO2- and Al2O3-Pillared Clays

AbstractTwo phyllosilicates (montmorillonite and saponite) have been selected as starting materials to synthesize ZrO2- and Al2O3-pillared clays by the insertion of polyoxocations and subsequent calcination. These pillared clays display higher surface area, porosity and available acid sites in comparison to their respective raw clays. These samples were tested in the one-pot process to transform furfural into obtain valuable products. The incorporation of ZrO2 allows to reach the highest furfural conversion values, with high yields towards furfuryl alcohol (FOL) at shorter reaction times, whereas the formation of i-propyl furfuryl ether (iPFE) is favored at longer times, attaining iPFE yields of about 50% after 24 h at 170 ºC, using isopropanol as sacrificing alcohol.

Facile Synthesis of Self-Supported Solid Amine Sorbents for Direct Air Capture.

Conventional usage of tetraethylenepentamine (TEPA) via being supported on porous solid materials for carbon capture is susceptible to oxidative degradation during regeneration cycles. This study reports a novel method to synthesize a TEPA based solid polymer for efficient CO2 removal via direct air capture (DAC). The polymer was obtained through epoxy-amine crosslinking reaction, leading to the transformation of liquid TEPA to a self-supported solid polymer. The synthesis was conducted under ambient conditions via a one-pot process with no waste products, which is aligned with green synthesis. The performance of the solid amine was evaluated in DAC under realistic conditions and compared with TEPA supported on SiO2 and zeolite 13X prepared through the conventional method. The solid TEPA amine exhibited a high CO2 uptake of 6.2 wt.% comparable to the conventional counterparts. More importantly, the solid TEPA amine demonstrated high resistance to oxidation during the accelerated ageing process at 80 °C in air for 24 h, whereas the two supported TEPA samples experienced severe degradation, with zeolite 13X supported TEPA incurring a reduction of 86.5 % in CO2 capturing capacity after the ageing. This work sheds light on the novel usage of TEPA as an efficient solid amine for practical DAC operation.

Improved performance of Pseudomonas fluorescens lipase immobilized on a magnetic mesoporous solvothermal hybrid-nanocarrier and its application in ultrasonication assisted estolide synthesis

The exponential growth of the biotechnological market necessitates the exploring novel, economically viable materials for enzyme immobilization to enhance the biocatalyst performance. This study involves preparing a hybrid carrier with a magnetic mesoporous nature, using milled rice husk (MRH) and multi-walled carbon nanotubes (MWCNTs) via a one-pot solvothermal process at 200 °C for 6 h. The carrier, rich in-NH2 groups, was chemically bonded to Pseudomonas fluorescens lipase (PFL) using EDC/NHS cross-linkers. The synthesized support achieved a maximum PFL loading of 94.92 mg of protein per gram of support. Moreover, the maximum activity recovery was achieved at 1196 %, under the optimal conditions: immobilization temperature 25℃, pH 9.0, immobilization time 2 h and PFL mass concentration 4 mg/mL. Subsequently, the derived enzyme was used to catalyze ricinoleic acid esterification to synthesize estolide under ultrasound-assisted conditions. The optimized principal parameters for reaction temperature, reaction time, and immobilized lipase loading were respectively determined to be 48.99 °C, 1.60 h, and 3.09 % via response surface methodology. Ricinoleic acid conversion reached 65.23 % under the optimal conditions with the assistance of 40 % power and 40 kHz ultrasonic frequency. Furthermore, remarkable operational stability was also observed, with a retention rate of 49.28 %, even after 10 consecutive batches. This study demonstrates promising prospects for industrial-scale application using ultrasound as a fast and ecologically friendly procedure.

Whole-cell one-pot biosynthesis of dodecanedioic acid from renewable linoleic acid

BackgroundDodecanedioic acid (DDA), a typical medium-chain dicarboxylic fatty acid with widespread applications, has a great synthetic value and a huge industrial market demand. Currently, a sustainable, eco-friendly and efficient process is desired for dodecanedioic acid production.ResultsHerein, a multi-enzymatic cascade was designed and constructed for the production of DDA from linoleic acid based on the lipoxygenase pathway in plants. The cascade is composed of lipoxygenase, hydroperoxide lyase, aldehyde dehydrogenase, and unidentified double-bond reductase in E. coli for the main cascade reactions, as well as NADH oxidase for cofactor recycling. The four component enzymes involved in the cascade were co-expressed in E. coli, together with the endogenous double-bond reductase of E. coli. After optimizing the reaction conditions of the rate-limiting step, 43.8 g L− 1 d− 1 of DDA was obtained by a whole-cell one-pot process starting from renewable linoleic acid.ConclusionsThrough engineering of the reaction system and co-expressing the component enzymes, a sustainable and eco-friendly DDA biosynthesis route was set up in E. coli, which afforded the highest space time yield for DDA production among the current artificial multi-enzymatic routes derived from the LOX-pathway, and the productivity achieved here ranks the second highest among the current research progress in DDA biosynthesis.Graphical