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The microstructures and mechanical properties of 7 at% Al-added VCoNi medium entropy alloy are studied and compared with those of the undoped alloy at various temperatures. Doping Al promotes the formation of a microstructure composed of the FCC matrix and the BCC-L2 1 phase, which remains stable until the matrix gradually transforms into the HCP-к and tetragonal-σ phases after 600 °C. Compared with the VCoNi alloy, the differences involve that the Al addition suppresses the strain-induced FCC-HCP transformation at 25 °C, and delays the eutectoid reaction at 700 °C. Corresponding to the microstructure evolution, the doped alloy preserves higher strength and strain hardening capacity until 600 °C due to the high-content harder BCC phase but comparable values at 700 and 800 °C with the relatively less HCP phase. Besides, the added Al can also reduce the susceptibility to the serration flow. The results reveal that the (VCoNi) 93 Al 7 alloy has high potentials for intermediate-temperature applications. • Doping Al promotes forming a heterogeneous duplex structure of FCC and BCC-L2 1 phases. • The structure stays stable until 600 °C and thereafter the matrix decomposes to the к and σ phases. • Al-doped MEA exhibits higher strength and SHR below 600 °C but comparable values at 700–800 °C. [ABSTRACT FROM AUTHOR]

Chinese biochemical engineering is committed to supporting the chemical and food industries, to advance science and technology frontiers, and to meet major demands of Chinese society and national economic development. This paper reviews the development of biochemical engineering, strategic deployment of these technologies by the government, industrial demand, research progress, and breakthroughs in key technologies in China. Furthermore, the outlook for future developments in biochemical engineering in China is also discussed. [ABSTRACT FROM AUTHOR]

In order to improve the overall properties and performance, a gradient nanostructured surface layer on AZ31B magnesium alloy was generated by newly developed surface nanocrystallization (SNC) and hardening process. In this paper, the surface mechanical rolling grinding treatment (SMRGT) was carried out at room temperature for the first time. The grain size refinement and working hardening were confirmed by the microstructure pictures, XRD results, and microhardness test; the reason of which is supposed to be the strain-induced plastic deformation during the SMRGT process. An average grain size of ~ 100 nm nanograins were observed on the uppermost surface, and grain size of the cross section increased gradually. The deformation twining was observed in the metallograph of local area of Mg alloy. The average microhardness of gradient nanograin (GNG) surface layer was 113 HV, which elevated by ~ 60% compared with the as-received substrate (average 66.1 HV). The mechanism of grain refinement is supposed to be the compressive strain-induced deformation twining, dislocation slip systems movement, the refinement effect of subgrain boundaries, and preferred orientation of local grains and boundaries. [ABSTRACT FROM AUTHOR]

Cofactors are involved in numerous intracellular reactions and critically influence redox balance and cellular metabolism. Cofactor engineering can support and promote the biocatalysis process, even help driving thermodynamically unfavorable reactions forwards. To achieve efficient production of chemicals and biofuels, cofactor engineering strategies such as altering cofactor supply or modifying reactants' cofactor preference have been developed to maintain redox balance. This review focuses primarily on the effects of cofactor engineering on carbon and energy metabolism. Coupling carbon metabolism with cofactor engineering can promote large-scale production, and even offer possibilities for producing new products or converting new materials. [ABSTRACT FROM AUTHOR]

Mannose-6-phosphate is an important phosphor-sugar, which is involved in many physiological functions and it is used to treat many diseases. Its production is however expensive since it requires costly substrate ATP as phosphorylation agent. This study has focused upon the direct synthesis of M6P by glucomannokinase using inorganic polyphosphate without involvement of ATP. The gene cloned for glucomannokinase has been sequenced from Mycobacterium phlei and it is transformed into Escherichia coli for expression. After purification involving affinity chromatography, a band of 30 kDa corresponding to the enzyme has been isolated from induced crude supernatant. A total amount of 0.69 mg/ml of enzyme has been successively obtained and the purity exceeds 90%. The kinetic assay studies show that this enzyme has more affinity towards polyphosphate and glucose than ATP and mannose respectively. The K M values of the enzyme for glucose, mannose, ATP and hexametaphosphate derived from experiments are 9.5, 203.7, 4.6, 1.7 μM, respectively. The enzyme has shown a maximum production of mannose-6-phosphate at optimized conditions of pH 8.5, 25 °C, poly(P)/mannose ratio 3:1 and in the presence of bivalent ion Mg 2+ . The results reveal that the glucomannokinase from Mycobacterium phlei suitable for further production of mannose-6-phosphate. [ABSTRACT FROM AUTHOR]

Abstract: The lubricants of the future have to be more environmentally adapted, have a higher level of performance. Synthesis esters (SEs) which can be used as raw materials for biodegradable lubricant base oils are increasing in popularity due to superior technical properties. Direct esterification of trimethylolpropane (TMP) with fatty acid in a solvent free system, by immobilized lipase from Candida sp. 99–125 was studied. Investigations of important factors were carried out involving temperature, time, enzyme amount, substrates molar ratio and water content. For 2g caprylic acid, under the optimal conditions, with 0.4g immobilized lipase, at substrates molar ratio 1:10 (TMP to acid), temperature 40°C and water content controlled under 0.8% (w/w), the total conversion of fatty acid with TMP reached up to 96% and the formation of trisubstituted TMP esters reached 93%. Water content controlled during esterification process was found to be critical for high yield of direct esterification. [Copyright &y& Elsevier]

Abstract: A novel lipase-catalyzed synthesis of aliphatic polyesters has been achieved successfully by using Candida sp.99-125 with diethyl sebacate and 1,4-butanediol as starting substrates in absence of organic solvents. The lipase from Candida sp.99-125 was employed for the first time to catalyze synthesis of poly(butylene sebacate) and showed high catalytic activity for bulkpolymerization under mild reaction conditions. The eco-friendly processes, without any environmental pollution, avoided both phase separation of the reactants and the use of toxic solvents effectively. The polycondensation reactions were performed in two stages: first stage reaction under atmospheric pressure to convert the monomers to oligomers followed by second stage reaction under vacuum process, with a highest molecular weight of 15,800 obtained in molar ratio of 1:1 at 70°C. The corresponding polyesters determined by thermogravimetric analysis (TGA) were much thermally stable up to 300°C. Differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXS) analysis demonstrated the polymers had a strong ability to crystallize with the degree of crystallinity up to 66%. [Copyright &y& Elsevier]

Abstract: Nonwoven fabrics of polypropylene (PP), polyethylene terephthalate (PET) and viscose fiber were used as novel and inexpensive support membranes for the immobilization of lipase. The use of a co-solvent during the immobilization process improved the activity of the coupled protein and the operational stability of PP and PET membranes. Covalent methods of immobilization caused the support membranes to become fragile and the lipase was easily deactivated. A hydrophobic treatment improved the protein-coupled content of silk cotton, viscose and PET surfaces more than threefold. Viscose prepared with the hydrophobic treatment could be reused up to 44 times and retained a static water contact angle of 131.8°. The initial rate of esterification remained high even when the amount of added water was increased to 10%. In a model application reaction of oleic acid and ethanol with 8% (v/v) added water, the acid conversion rate of post-hydrophobic treated immobilized lipase improved by at least 10% in each of five batches. These results suggest that a hydrophobic surface results in a lower amount of adsorbed water on the support membrane and provides a more suitable microenvironment for the enzymes. Nonwoven viscose could be a potential enzyme immobilization matrix for industrial processes. [Copyright &y& Elsevier]

A novel lead-free foil (AlMgGaLi) with a melting point of 398.3 ~ 414.8 °C was developed for active soldering of copper to aluminum matrix composite. The effect of joining pressure on the microstructure, interface wetting and shear strength of the dissimilar joints was analyzed. When the joining pressure increased to 1 MPa, an Al-based solid solution with an atomic composition of 89.62% Al, 6.5% Mg, 3.1% O, 0.46% Cu, 0.23% Ga and 0.09% Si was formed within the bond seam and the thickness of the transition layer with copper dissolution was approximately 4.9 μm. The joining pressure improved the interfacial wettability of the dissimilar joint by enhancing mutual diffusion with a shortened interface layer, tailored the runout and the formation of bond seam, and controlled an appropriate thickness of the copper dissolution transition layer. Sound joint with a maximum shear strength of 94 MPa (~ 80% of parent composites) is achievable at 450 °C using the joining pressure of 1 MPa. The failure mechanism of the joints with the AlMgGaLi foil under shear stress has been revealed from the analysis on the interface layers of the joints with SEM/EDX/XRD. Our studies provide an important guideline for using an AlMgGaLi and other similar fillers for a successfully joining of copper to Al-MMCs for high-temperature and high-power electronic devices. [ABSTRACT FROM AUTHOR]

Biolubricants produced by chemically modifying vegetable oils are promising to replace mineral-based lubricants. However, the performances of biolubricants synthesized through traditional chemical modification routes, such as transesterification/esterification, epoxidation with further ring opening, and estolide formation, cannot satisfy the demands of extreme conditions. Meanwhile, complicated multi-step reactions cause expensive costs, which hinders their large-scale application. In this study, pelargonic acid (PA) derived from the cleavage of oleic acid was esterified with trimethylolpropane (TMP) to produce branched-chain esters (tri-TMP esters) catalyzed by the lipase (Candida sp. 99–125), focusing on batch stability of the lipase, thermal-oxidation stability and lubrication performance of the product. The lipase maintained high activity for 4 continuous batches in 5 L enzyme reactor with the conversion of PA > 96% and the accumulation of tri-TMP esters > 84% in each batch. The obtained tri-TMP esters had a pour point of − 56 °C, a viscosity index of 137, and a flash point of 276 °C. Anti-oxidation stability test and thermogravimetric behaviors showed that the biolubricant had favorable thermal-oxidative stability. Friction tests verified that the product displayed excellent lubrication performance with a minimum coefficient of friction (COF) of 0.099 and an average wear spot diameter (WSD) of 221.5 µm. The green and high-selective synthetic pathway fills the defect of existing routes for the preparation of biolubricants from chemically modified vegetable oils. [Display omitted] • Lipase-catalyzed synthesis of branched-chain esters based on PA and TMP was proposed. • The lipase maintained high activity for 4 continuous batches. • The tri-TMP esters has superior low-temperature performance and thermal-oxidative stability. • This biolubricant displayed excellent lubrication performance in HFRR tests. [ABSTRACT FROM AUTHOR]

β-Farnesene is an advanced molecule with promising applications in agriculture, the cosmetics industry, pharmaceuticals, and bioenergy. To supplement the shortcomings of rational design in the development of high-producing β-farnesene strains, a Metabolic Pathway Design-Fermentation Test-Metabolomic Analysis-Target Mining experimental cycle was designed. In this study, by over-adding 20 different amino acids/nucleobases to induce fluctuations in the production of β-farnesene, the changes in intracellular metabolites in the β-farnesene titer-increased group were analyzed using non-targeted metabolomics. Differential metabolites that were detected in each experimental group were selected, and their metabolic pathways were located. Based on these differential metabolites, targeted strain gene editing and culture medium optimization were performed. The overexpression of the coenzyme A synthesis-related gene pantothenate kinase (PanK) and the addition of four mixed water-soluble vitamins in the culture medium increased the β-farnesene titer in the shake flask to 1054.8 mg/L, a 48.5% increase from the initial strain. In the subsequent fed-batch fermentation, the β-farnesene titer further reached 24.6 g/L. This work demonstrates the tremendous application value of metabolomics analysis for the development of industrial recombinant strains and the optimization of fermentation conditions. [ABSTRACT FROM AUTHOR]

Utilization of one-carbon chemicals such as CO 2 , formate, and methanol by microorganisms can enable the sustainable production of fuels and chemicals. However, the low conversion efficiency of these chemicals by microorganisms is a major challenge. To address this, we designed a one-carbon strategy that can utilize CO 2 and its derivative formate. Here, a platform yeast strain with improved formate utilization and NAD(P)H production was constructed and evaluated for its ability to produce free fatty acids (FFAs). Based on 13C-marked analysis, the one-carbon assimilation efficiency of the platform strain reached 11.24%. Through continuous optimization, under conditions of glucose feeding the formate utilization rate of the final strain reached 0.48 g/L/h, with the final titer of FFAs reached 10.1 g/L, which represented improvements of 21.8 times and 33.7 times, respectively. As such, the produced FFAs can be easily transformed into biodiesel by combining them with downstream technologies in future research. [Display omitted] [ABSTRACT FROM AUTHOR]

Glycerol waste from the biodiesel production can be used as a carbon source in the production of 1,3-propanediol (1,3-PD) through microbial fermentation. However, downstream processing is a major bottleneck that restricts its biological production. Here, we investigated an environmentally-friendly method to enzymatically separate 1,3-PD. The transformation of 1,3-PD to an ester was achieved by exploiting the esterification reaction with fatty acids under lipase catalysis. The reaction efficiency was optimized using different poly-alcohols that were existed in the fermentation broth reacted with a fatty acid. Whereas the 1,3-PD conversion reached 62%, only a 0.06% and 0.08% conversion was reached for 2,3-butanediol and glycerol, illustrating the former’s more efficient separation. The recovery efficiency of 1,3-PD was 96%. Finally, 1,3-PD was obtained by lipase-directed ester hydrolysis. Taken together, the bio-catalyzed separation process presented here is a novel and promising method for recovering 1,3-PD. [ABSTRACT FROM AUTHOR]

For transient liquid phase bonding of as-cast 70 vol.% SiCp/A356 composite, Al-24Mg-16Ga-1Ti (wt.%) active braze was designed by adding Ti as melting point increaser (MPI) for Al into Al-Mg-Ga active alloy near eutectic composition to produce in-situ reinforcement by precipitating a fine and dispersive Ti-containing intermetallic compound as reinforcement within the solid-solution bond seam after isothermal solidification. Bonding was performed at three temperature levels of quasi-melting (450 °C), just fully melting (500 °C), and over melting (550 °C) for the braze under 0.5–1.75 MPa in argon. The braze was able to produce fine (less than 1 μm) and dispersive Ti-containing precipitated phase (Al-2Mg-1Ga-0.5Ti, at.%) as in-situ reinforcement only at 500 °C under medium pressure (1–1.5 MPa), increasing bond seam microhardness by 30 Hv over the matrix. The braze robustly showed good wettability for each temperature due to the matrix dissolution and detectable amorphous reaction products containing Mg and Ga on SiC surface. Higher temperature caused coarsening of needle-like Si-containing Al-Si-Ti precipitated phase while higher pressure produced blocky Al 3 Ti with a shell of Mg and Ga. Sound joint produced at 500 °C under 1.5 MPa with 118.6 MPa shear strength (98.8% parent composite) fractured completely within the composite. [ABSTRACT FROM AUTHOR]

Different plasticizers have obvious differences in plasticizing properties. As one of the important indicators for evaluating plasticization performance, the substitution factor (SF) has great significance for product cost accounting. In this research, a genetic algorithm with "variable mutation probability" was developed to screen the key molecular descriptors of plasticizers that are highly correlated with the SF, and a SF prediction model was established based on these filtered molecular descriptors. The results show that the improved genetic algorithm greatly improved the prediction accuracy in different regression models. The coefficient of determination (R2) for the test set and the cross-validation both reached 0.92, which is at least 0.15 higher than the R2 of the unimproved genetic algorithm. From the results of the selected descriptors, most of the descriptors focused on describing the branching of the molecule, which is consistent with the view that the branching chain plays an important role in the plasticization process. As the first study to establish the relationship between plasticizer SF and plasticizer molecular structure, this work provides a basis for subsequent plasticizer performance and evaluation system modeling. [ABSTRACT FROM AUTHOR]

Using pine pollen as a new biological template, Ce-doped TiO2 porous microspheres were prepared via the sol–gel method and impregnation method after high-temperature calcination. The samples were characterized using scanning electron microscopy, X-ray energy spectrum analysis, X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, electrochemistry, and electron spin resonance spectroscopy. Owing to the doping of cerium, the bionic material showed a better photocatalytic antibacterial performance, and the antibacterial rate against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis surpassed 99.9% within 120 min under xenon lamp irradiation. In addition, we discuss the photocatalytic sterilization mechanism of porous Ce-doped TiO2 microspheres. The antibacterial activities of this biomimetic material are mainly due to the reactive oxygen species produced by its photocatalysis; these species attack bacteria, causing them to cleave and die. Inspired by natural pollen, the materials were prepared, and they have broad application prospects for photocatalytic disinfection. [ABSTRACT FROM AUTHOR]

Background: Microbial electricity production has received considerable attention from researchers due to its environmental friendliness and low price. The increase in the number of intracellular electrons in a microbial fuel cell (MFC) helps to improve the MFC performance. Results: In this study, we accumulated excess electrons intracellularly by knocking out the gene related to intracellular electron consumption in Saccharomyces cerevisiae, and the elevated intracellular electron pool positively influenced the performances of MFCs in terms of electricity production, while helping to increase ethanol production and achieve ethanol and electricity co-production, which in turn improved the utilization of substrates. The final knockout strain reached a maximum ethanol yield of 7.71 g/L and a maximum power density of 240 mW/m2 in the MFC, which was 12 times higher than that of the control bacteria, with a 17.3% increase in energy utilization. Conclusions: The knockdown of intracellular electron-consuming genes reported here allowed the accumulation of excess electrons in cells, and the elevated intracellular electron pool positively influenced the electrical production performance of the MFC. Furthermore, by knocking out the intracellular metabolic pathway, the yield of ethanol could be increased, and co-production of ethanol and electricity could be achieved. Thus, the MFC improved the utilization of the substrate. [ABSTRACT FROM AUTHOR]

Bio-recycling of plastic waste is a promising solution to plastic pollution. As one of the most abundant plastic wastes, polyethylene terephthalate (PET) can be degraded by carboxylic ester hydrolases (EC 3.1.1). Nevertheless, the biological PET hydrolysis efficiency is always limited by the low activity and poor thermostability of the enzymes. Herein, to address the above barriers, we rationally mutated the relevant sites of Thermobifida cellulosilytica cutinase 1 (ThcCut1) involved in substrate binding. The wider substrate-binding pockets after mutation could facilitate the accessibility of the enzyme to the substrate. Divalent metal-binding sites were further predicted and substituted with disulfide bonds, with the aim of effectively improving the thermostability of the mutant ThcCut1. Coupled with sequence alignment and structural dynamics analysis, the ThcCut1-D205C/E254C/Q93G variant with a melting temperature exceeding the glass transition temperature of recycled PET was constructed. After comprehensively screening the active and thermally stable mutation sites, the resulting ThcCut1-G63A/F210I/D205C/E254C/Q93G (ThcCut1-AICCG) variant exhibited high enzymatic activity at a high temperature (70 °C). As result, 96.2% of the post-consumer PET bottle particles (without energy-intensive melt-quenching pretreatment) can be successfully degraded after 96 h of hydrolysis using ThcCut1-AICCG, which was 87.5 times higher than that using the wild-type ThcCut1. This novel strategy for amino acid site analysis will facilitate the modification of homologous cutinases to improve the catalytic performance, and provide a reliable technical method for constructing a PET hydrolase modification platform. [ABSTRACT FROM AUTHOR]

[Display omitted] • PET hydrolases can be purified by heating process. • The performance for various PET hydrolases purified by heating was analyzed. • Protectants and duration affected heat purification. • The purified hydrolases exhibited good hydrolysis activity for PET degradation. In this study, a novel high-purity polyethylene terephthalate (PET) hydrolase purification method was suggested, which was based on a simple heating protocol. To test the applicability of the method, the heating purification performances of different types of thermo-resistant PET hydrolases, including ThcCut1, ThcCut2, TfCut2, TfCut2-G62A, TfCut2-G62A/F209A, and LCC-F243I/D238C/S283C/Y127G, from crude extract were conducted. During the process, the effect of protectants and treatment duration on proteins and activity recoveries were tested. Results indicated that the specific activities of PET hydrolases purified by heating were generally as competitive as the ones purified by conventional nickel column methods, with higher protein recovery and enzyme activity recovery. The practical application of the heating purified PET hydrolases was further evaluated. Except for ThcCut2, other PET hydrolases exhibited better degradation performances of PET nanoparticles. The novel heating purification method for PET hydrolases showed good applicability, which can be extended to purify other thermo-resistant enzymes. [ABSTRACT FROM AUTHOR]

• A photo-enzyme nanosystem for CO 2 reduction was constructed. • In-CdS was prepared to improve its photocatalytic performance. • NADH regeneration yield of 10 %In-CdS@ZIF-8 is 94.10 %. • FDH was immobilized to produce 267.18 μM HCOOH. • 85.98% of the residual activity was retained after reusing 8 times. Replacement of fossil fuel by renewable resources is a central resource and energy efficiency strategy, where CO 2 is the key molecule to proceed effectively in this direction. Here, we synthesized In-doped CdS and constructed a new photo-enzyme nanosystem 10 %In-CdS@ZIF-8&FDH, which can catalyze CO 2 to formic acid (HCOOH) via formate dehydrogenase immobilized on ZIF-8 while photocatalytic regenerating NADH via indium-doped CdS. Indium doping greatly enhances the photocatalytic performance of CdS. The NADH regeneration rate reaches 94.10 %. The nanosystem can produce 267.18 μM HCOOH, which is 4.27 times that of the free enzyme system. And 85.98 % of the residual activity can be retained after reusing 8 times. This study will inspire more research efforts for light-driven enzymatic nanosystems in CO 2 fixation and lay the foundation for realizing renewable energy-driven CO 2 conversion to produce chemical products. [ABSTRACT FROM AUTHOR]

• Created a precise and controllable enzyme cross-linking method. • Expanded the application of microbial transglutaminase in multi-enzyme assembly. • Constructed a double enzyme system for efficient conversion of CO 2 to formic acid. • This cross-linking method hardly affects enzyme activity. • Improved thermal stability of cross-linked enzyme. Inspired by the cascades performed in vivo , the assembly of multiple enzymes in vitro has strongly moved into the focus of researchers in the field of biocatalysis. In this study, a new, mild and accurate enzyme cross-linking method is revealed. Microbial transglutaminase (MTG) acts as a "cross-linking medium" by identifying the amide group of the glutamine and the primary amine group of lysine in the artificial peptide tags specifically to form an iso-peptide bond. Here, carbonic anhydrase (CA) and formate dehydrogenase (FDH) with different peptide tags that can be recognized by MTG were linked together to obtain different proportions of cross-linked enzymes for efficient conversion of greenhouse gas carbon dioxide to formic acid. After cross-linking, we obtained "one-to-one" and "one-to-more" cross-linked enzyme aggregates. There is a minor residual loss of the two enzymes, the remaining enzyme activity of CA is more than 93%, and the remaining enzyme activity of FDH is more than 84%. In particular, the overall catalytic efficiency of the cross-linked enzyme is increased by 5.8 times compared with free enzymes and the thermal stability of FDH at different temperatures is improved. The applied strategy demonstrates the potential application of MTG in multi-enzyme assembly and synthetic biology. [ABSTRACT FROM AUTHOR]

CO 2 is one of the main gases leading to the greenhouse effect. The use of a multi-enzyme biological carbon capture and utilization method can reduce the concentration of CO 2. However, most oxidoreductases require NADH as a coenzyme, which is too expensive to afford for most situation. In this research, NADH was regenerated using photocatalysis and CO 2 was converted to formaldehyde by FateDH and FaldDH gradually. TCPP and ZIF-8 were successfully combined to construct a photocatalytic multi-enzyme cascade biomimetic carbon sequestration system for the first time. TCPP was used as the photocatalyst and ZIF-8 was used as the multi-enzyme immobilized carrier for FateDH and FaldDH. The TCPP content, material dosage, pH of reaction solution and the ratio of the two enzymes were optimized in this study. The results indicated that when reacting under visible light for 3 h, using 1 mg/mL 3% TCPP @ZIF-8 at pH 8.0 PBS condition, it has the highest NADH reduction rate, reaching 75.04%. It was also found that when FateDH: FaldDH = 2:1, the formaldehyde yield can reach up to 7.74 μM. And the formaldehyde conversion rate reached 77.37%. In addition, this composite system retained 52.93% of residual activity after 10 batches of re-use. • A photocatalytic multi-enzyme cascade carbon sequestration system was constructed. • Coupled TCPP and ZIF-8 were used for regeneration of NADH with a yeild of 75.04%. • FateDH and FaldDH were immobilized to produce HCHO from CO 2 with a yeild of 77.37%. • The carbon sequestration system can be reused for 10 times. [ABSTRACT FROM AUTHOR]

Due to the poor biodegradability and toxicity of mineral-based lubricants, the development and application of plant-based biolubricants are increasing. However, low stability and poor low temperature performance restrict plant oils to use as lubricants directly. Hence, the paper tried to find an efficient and green way to modify the plant oil derivate oleic acid and obtained high-performance biolubricants. This study demonstrated that modification of oleic acid through epoxidation combined with ring opening reaction, and further esterification, was an efficient strategy for modifying unsaturated fatty acids for the biolubricant production. Meanwhile, catalytic effects of ionic liquids were compared with other catalysts. The results indicated that ionic liquid [HMIm][PF6] is an efficient catalyst for the ring opening and esterification for the synthesis of biolubricants with different kinds of fatty acids. Modified biolubricants from this research exhibited excellent viscosity index (>116) and low temperature performance (pour point < −48 °C). The results of high frequency reciprocating friction experiments exhibited superior lubrication performance of the lubricant. These findings provide a new green and efficient method for improving plant oils as biolubricants. Image 1 • Green way to produce high-performance biolubricant from oleic acid was developed. • Esterification after epoxide ring-opening is efficient for lubricant production. • Catalytic effects of ionic liquids were compared with other reported catalysts. • Biolubricant from this research exhibited excellent low temperature performance. [ABSTRACT FROM AUTHOR]

Due to the poor biodegradability and toxicity of mineral-based lubricants, the development and application of plant-based biolubricants are increasing. However, low stability and poor low temperature performance restrict plant oils to use as lubricants directly. Hence, the paper tried to find an efficient and green way to modify the plant oil derivate oleic acid and obtained high-performance biolubricants. This study demonstrated that modification of oleic acid through epoxidation combined with ring opening reaction, and further esterification, was an efficient strategy for modifying unsaturated fatty acids for the biolubricant production. Meanwhile, catalytic effects of ionic liquids were compared with other catalysts. The results indicated that ionic liquid [HMIm][PF6] is an efficient catalyst for the ring opening and esterification for the synthesis of biolubricants with different kinds of fatty acids. Modified biolubricants from this research exhibited excellent viscosity index (>116) and low temperature performance (pour point < −48 °C). The results of high frequency reciprocating friction experiments exhibited superior lubrication performance of the lubricant. These findings provide a new green and efficient method for improving plant oils as biolubricants. Image 1 • Green way to produce high-performance biolubricant from oleic acid was developed. • Esterification after epoxide ring-opening is efficient for lubricant production. • Catalytic effects of ionic liquids were compared with other reported catalysts. • Biolubricant from this research exhibited excellent low temperature performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • PAN MPs enriched the secretion of extracellular polymeric substance. • Granular breakage occurred at 100 mg/L PAN MPs. • Phylum Proteobacteria played a dominant role in resistance to PAN MPs. • PAN MPs inhibited membrane transport and denitrification functional genes. Aerobic granular sludge (AGS) has proved to be a promising biotechnology for microplastics wastewater treatment. However, polyacrylonitrile microplastics (PAN MPs), the most widely used plastic in textile materials, have not been investigated. Therefore, the effect of the neglected PAN MPs on AGS at different concentrations (1, 10, and 100 mg/L) was evaluated. The results indicated that PAN MPs with 1 and 10 mg/L concentrations had no obvious effect on granular stability and nutrient removal performance, but greatly promoted the secretion of EPS. Remarkably, the granule structure was severely damaged under 100 mg/L PAN MPs. Moreover, microbial community analysis showed that phylum Proteobacteria played a dominant role in resistance to PAN MPs. Metabolic analysis further revealed that genes related to denitrification pathway (nasA, nirK, nirS and norB) and membrane transport were significantly inhibited under PAN MPs stress. This study may provide additional information on the treatment of microplastics wastewater using AGS. [ABSTRACT FROM AUTHOR]

[Display omitted] • The expression of mcMAE promoted the accumulation of β-farnesene. • Expressing mmACL and modulating citrate metabolism enhanced acetyl-CoA supply. • The orthogonal precursor pathways contribute to maximizing β-farnesene production. • An optimized fermentation process resulted a titer of 28.9 g/L of β-farnesene. β-Farnesene is a sesquiterpene commonly found in essential oils of plants, with applications spanning from agricultural pest control and biofuels to industrial chemicals. The use of renewable substrates in microbial cell factories offers a sustainable approach to β-farnesene biosynthesis. In this study, malic enzyme from Mucor circinelloides was examined for NADPH regeneration, concomitant with the augmentation of cytosolic acetyl-CoA supply by expressing ATP-citrate lyase from Mus musculus and manipulating the citrate pathway via AMP deaminase and isocitrate dehydrogenase. Carbon flux was modulated through the elimination of native 6-phosphofructokinase, while the incorporation of an exogenous non-oxidative glycolysis pathway served to bridge the pentose phosphate pathway with the mevalonate pathway. The resulting orthogonal precursor supply pathway facilitated β-farnesene production, reaching 810 mg/L in shake-flask fermentation. Employing optimal fermentation conditions and feeding strategy, a titer of 28.9 g/L of β-farnesene was attained in a 2 L bioreactor. [ABSTRACT FROM AUTHOR]

Mannose-6-phosphate (M6P) is involved in many metabolic pathways in life, and it has important applications in the treatment of diseases. This study explored a cost-effective enzyme catalytic synthesis method of M6P, using polyphosphate-dependent mannose kinase from Arthrobacter species. This synthesis uses polyphosphate to replace expensive ATP, and it is greener and safer than chemical synthesis. This study investigated the effects of key factors such as metal ions, temperature, and substrate addition on this enzymatic reaction, and improved the conversion efficiency. We moreover take advantage of the response surface method to explore the best catalytic conditions synthetically. The conversion was 99.17% successful under the optimal reaction conditions. After a series of optimizations, we carried out a 200 mL scale-up experiment, which proved that the method has good prospects for industrial applications. [ABSTRACT FROM AUTHOR]

A sensitive LC–MS/MS method was established to quantify diols and glycerol in fermentation broth using trichloroacetyl isocyanate as instantaneous derivatization reagent for monitoring the production of 1,3-propanediol and 2,3-butanediol from the biodiesel biorefinery process. Due to the derivatization reaction was very quickly at room temperature, only 1 min was needed for the reaction process. In addition, both extraction of analytes and evaporation of water were not employed in the analytical procedure. Furthermore, the isotope of chlorine was beneficial for understanding of the secondary mass spectrum and avoiding false positive results. Therefore, much more accurate results of diols and glycerol concentration in fermentation could be obtained even at very low levels for the evaluation of microbial metabolism pathway modification. [ABSTRACT FROM AUTHOR]

In this work, the acetone-butanol-ethanol (ABE) fermentation was upgraded in order to improve its economy. Fed-batch fermentation was integrated with two-stage gas stripping-pervaporation unit. The permeated ABE condensate was used as substrate for oleates production. Candida sp. 99–125 cells, being rich in lipase activity, were used as full-cell catalyst. Different ABE feeding strategies in the esterification process were compared. As results, 10.1%, 68.6% and 72.5% of butyl oleate were obtained in the one-step added scenario, the stepwise-added scenario, and the simultaneous fed-batch scenario, respectively. The novel hybrid process was energy-saving, environmentally friendly and profitable, showing promise in future industrialization. [ABSTRACT FROM AUTHOR]

Hybrid process that integrated fermentation, pervaporation and esterification was established aiming to improve the economic feasibility of the conventional acetone-butanol-ethanol (ABE) fermentation process. Candida sp 99–125 cells were used as full-cell catalyst. The feasibility of batch and fed-batch esterification using the ABE permeate of pervaporation (ranging from 286.9 g/L to 402.9 g/L) as substrate were compared. Valuable butyl oleate was produced along with ethyl oleate. For the batch esterification, due to severe inhibition of substrate to lipase, the yield of butyl oleate and ethyl oleate were only 24.9% and 3.3%, respectively. In contrast, 75% and 11.8% of butyl oleate and ethyl oleate were obtained, respectively, at the end of the fed-batch esterification. The novel integration process provides a promising strategy for in situ upgrading ABE products. [ABSTRACT FROM AUTHOR]

In this work, phytosterol ester was synthesized using Yarrowia lipolytica lipase Ylip2 that had been immobilized on inorganic support in a solvent-free system and reacted in a computer-aided water activity controlled bioreactor. The immobilization of Ylip2 on celite led to a remarkable increase in the phytosterol conversion compared to that of free lipase. An investigation of the reaction conditions were oleic acid as the fatty acid variety, 10,000 U/g substrate, and a temperature of 50 °C for phytosterol ester synthesis. Controlling of the water activity at a set point was accomplished by the introduction of dry air through the reaction medium at a digital feedback controlled flow rate. For the esterification of phytosterol ester, a low (15%) water activity resulted in a considerable improvement in phytosterol conversion (91.1%) as well as a decreased reaction time (78 h). Furthermore, Ylip2 lipase immobilized on celite retained 90% esterification activity for the synthesis of phytosterol oleate after reused 8 cycles, while free lipase was only viable for 5 batches with 90% esterification activity remained. Finally, the phytosterol oleate space time yield increased from 1.65 g/L/h with free lipase to 2.53 g/L/h with immobilized lipase. These results illustrate that the immobilized Yarrowia lipolytica lipase Ylip2 in a water activity controlled reactor has great potential for the application in phytosterol esters synthesis. [ABSTRACT FROM AUTHOR]

Vitamin E (VE) has significant biological activities and thus its acylation to increase its stability is of extreme interest. We developed an efficient and sustainable approach using imidazolium-based ionic liquids as dual solvent-catalysts for the esterification between α-tocopherol (the most active form of VE) and succinic anhydride. Although in literature it is reported that lipase can catalyze this reaction, hereby we demonstrate that the reaction observed in DMSO and DMF is catalyzed by the histidyl residues of the protein. Histidine and its analogue containing an imidazole ring were tested as organocatalysts for the production of α-tocopherol succinate. In light of the imidazole organocatalysis, commercially-available 3-alkyl-1-methyl imidazolium ILs [CnC1Im][X−] were investigated as dual solvent-catalysts for the esterification of α-tocopherol with succinic anhydride, and provided satisfactory yields and reaction rates. [C5C1Im][NO3−] can be recycled by water extraction, instead of organic solvent extraction to separate α-tocopherol succinate from [C5C1Im][NO3−], with an average yield of 94.1% for 4 subsequent batches, while the catalytic activity of the recycled ILs showed almost no loss after 4 batches. The developed protocol for the synthesis of α-tocopherol esters and IL recycling bears industrial potential due to the ease of use and the efficient recycling. [ABSTRACT FROM AUTHOR]

A lipase from the yeast Yarrowia lipolytica was immobilized on a PDMS-modified nonwoven viscose fabric and used in the synthesis of ethyl oleate. The efficiency of immobilization improved to 75.2% when the concentrated lipase slurry (180 mg mL −1 ) was used as the source of lipase. When compared with the original immobilized lipase, the lipase immobilized on the PDMS-modified fabric exhibited more stable catalytic activity over 35 batches; exhibited a 20-fold lower affinity for oleic acid, a 42-fold less ethanol-induced inhibition; could be reused in 10 iterative 5L batch stirred tank reactor processes. When compared to that of free lipase, the pH stability range of immobilized lipase was narrower (pH 6–7 vs pH 5–8); the optimum reaction temperature was higher (40 °C vs 37 °C); and the thermally more stable (70% vs 5% of activity was retained after pre-incubation for 4 h at 45 °C). The variation in the activity exhibited in an organic solvent could be correlated to the log P. Catalytic efficiency was ∼13-fold lower upon excessive lipase immobilization. XPS/ATR-FTIR confirmed the introduction of PDMS onto lipase-immobilized viscose. The simple enzyme immobilization method could potentially be useful for the production of ethyl oleate at an industrial scale. [ABSTRACT FROM AUTHOR]

We have developed an improved and effective method to immobilize Yarrowia lipolytica lipase Lip2 (YLIP2) on an epoxy poly-(glycidylmethacrylate-triallyisocyanurate-ethyleneglycoldimethacrylate) (P GMA-TAIC-EGDMA ) support structure with or without amine or/and protein modifications. Our results show that there is an increase in the activity of the immobilized lipase on n-butylamine (BA) modified support (420 U/g support) and the biocompatible gelatin modified support (600 U/g support) when compared to the support without modification (240 U/g support). To further study the influences of BA and gelatin modification on the activity of the immobilized lipase, gelatin and BA were concurrently used to decorate the support structure. Lipase immobilized on 2% BA/gelatin (1:1) modified support obtained the highest activity (1180 U/g support), which was five-fold higher than that on a native support structure. These results suggest that the activity of a support-immobilized lipase depends on the support surface properties and a moderate support surface micro-environment was crucial for elevated activity. Collectively, these data show that a combined gelatin and BA modification regulates the support surface more suitable for immobilizing YLIP2. [ABSTRACT FROM AUTHOR]

ExtracellularYarrowia lipolyticalipase Lip2 (YLIP2) demonstrated an (R)-enantiopreference for efficient resolution of (R,S)-1-phenylethanol by solvent engineering with different kinds of binary solvent. The enantioselectivity was significantly improved by the addition of 1, 4-dioxane. The reaction parameters including co-solvent concentration, reaction temperature, and the reaction time were optimized. When the reaction was carried out with n-hexane in the presence of 0.8% 1,4-dioxane at 50°C for 72 h, the enantiomeric excess of product markedly increased to 99.1% from 66% in pure n-hexane; the enantiomeric ratio was higher than 200, which was 500-fold compared with that in pure n-hexane. The results indicated that it is very important to design the proper co-solvents, especially to create appropriate micro-environment for YLIP2 for catalyzing the resolution of (R,S)-1-phenylethanol. [ABSTRACT FROM AUTHOR]

An enzymatic process using a packed bed bioreactor with recirculation was developed for the scale-up synthesis of 2-ethylhexyl palmitate with a lipase fromCandidasp. 99–125 immobilized on a fabric membrane by natural attachment to the membrane surface. Esterification was effectively performed by circulating the reaction mixture between a packed bed column and a substrate container. A maximum esterification yield of 98% was obtained. Adding molecular sieves and drying the immobilized lipase both decreased the water content at the reactor outlet and around the enzyme, which led to an increase in the rate of esterification. The long-term stability of the reactor was tested by continuing the reaction for 30 batches (over 300 h) with an average esterification yield of about 95%. This immobilized lipase bioreactor is scalable and is thus suitable for industrial production of 2-ethylhexyl palmitate. [ABSTRACT FROM AUTHOR]

Finishing of silk fabric was achieved by using amino-functional polydimethylsiloxane (PDMS) and lipase from Candida sp. 99-125 was immobilized on the treated silk fabrics. Hydrophobic fabrics were obtained by dipping the native fabric in 0.125-0.25% (w/v) PDMS solution and dried at 70°C. The direct adsorption on PDMS-treated fabric was verified to be a better strategy for lipase immobilization than that by covalent binding. Compared to unfinished fabrics, the hydrolytic activity of immobilized enzyme on the finished fabric was improved by 1.6 times. Moreover, the activity of immobilized enzymes on hydrophobic fabrics was significantly improved in different concentrations of strong polar solvents such as methanol and ethanol, and in common organic solvents with different octanol-water partition coefficients (LogP). Enzymatic activity and stability in 15% water content system (added water accounted for the total reaction mixtures, v/v) showed more than 30% improvement in each batch. The amino-silicone finished fabric surface was investigated by scanning electron microscopy and X-ray photoelectron spectroscopy. The hydrophobic fabric immobilized enzyme could be recycled for more than 80 times with no significant decrease in esterification activity. PDMS-treated woven silk fabrics could be a potential support for lipase immobilization in catalytic esterification processes. [ABSTRACT FROM AUTHOR]

Highlights: [•] Lipase was absorbed on surface hydrophobic modified silk fibers. [•] Immobilized lipase and feeding methods improve synthesis of tri-TMP esters. [•] Immobilized lipas showed increase esterification activity and decrease hydrolysis activity. [•] TMP-feeding methods kept a high molar ratio of fatty acid to TMP during process. [Copyright &y& Elsevier]

Methanol is regularly used as a substratefor biodiesel synthesis.Excess methanol can however inhibit the lipase activity. In the presentwork, the activity and conformational changes of Yarrowialipolyticalipase (LIP2) at different concentrationsof methanol were investigated by measuring fluorescence, UV–visspectra, and molecular dynamics simulations. The lipase tended toexpand at higher concentrations of methanol, and the methanol moleculeswere able to enter into the LIP2, leading to microenvironment changesaround the aromatic amino acids. More hydrophobic groups were exposedto the solvents at high methanol concentrations, and the originalhydrophobic interaction in the protein was destroyed, thus resultingin the tertiary structure change of the lipase. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ordered self-assembled system formed when enzyme ratio match graft ratio. • CG-MD was used to reveal the self-assembly of GOX-CD and CAT-AD. • Non-ideal enzyme ratio will cause enzyme self-aggregation. • Self-assembly is not easy to occur under low grafting rate. The self-assembly system of glucose oxidase (GOX) and catalase (CAT) constructed by supramolecular recognition between β-cyclodextrin (β-CD) and adamantane (AD) can effectively increase the yield of gluconic acid. However, it is still not clear how the β-CD/AD grafting rate affects the process of self-assembly and the optimal enzyme ratio. In this work, molecular dynamics simulation based on the coarse-grained (CG) method was applied to simulate the self-assembly process between two enzymes. Compared with the low grafting situation, the high grafting situation realizes the self-assembly process within the reasonable simulation time scale. The results of different enzyme ratios also show great differences under different grafting situations. An ordered supramolecular self-assembly structure can only be formed when the ratio of enzymes (1:2) matches the grafting rate (2:1). The self-aggregation of GOX or CAT occurred in other systems and CAT shows stronger self-aggregation ability. [ABSTRACT FROM AUTHOR]

Highlights: [•] A simple, efficient immobilization protocol on polyurethane foam was developed. [•] Polyethyleneimine (PEI) was used to regulate the micro-environment. [•] Immobilized lipase exhibited a long operational stability in esterification system. [Copyright &y& Elsevier]

Abstract: Diesters and diols were successfully converted into aliphatic polyesters by enzymatic lipase Candida sp.99-125 catalysis, with β-cyclodextrin acting as supporting architecture (in a similar way as chaperone proteins). No organic solvents were used. The polytransesterification was a much greener process, being solvent-free and without metal residues. Lipase Candida sp.99-125 showed a high catalytic activity for bulkpolymerization of diesters and diols with various numbers of methylene groups in their chains. β-Cyclodextrin encircled the linear polymer chain and maintained the chain in a proper configuration to avoid its coagulation. Lipase initiated the polymerization and β-cyclodextrin threaded onto the polymer chain to control the structure for producing high molecular weight polyesters. From a combination of diesters and diols, polyesters with a high molecular weight of 62,100Da were obtained at 70°C. The corresponding polyesters showed an excellent thermal stability till 350°C and had a strong ability to crystallize with up to 72% crystallinity, contributing to their high storage modulus. [Copyright &y& Elsevier]

Abstract: As a stable substitute of Vitamin C, l-ascorbyl-2-monophosphate (AMP) has many applications, such as skin protecting, skin treatment, and fish diary feed. For decades, several methods were developed for the production of AMP. However, no purification process with high yield, short route and limited waste production, was developed. As an environment friendly separation method, electrodialysis was introduced into the production of l-ascorbyl-2-monophosphate for the first time in this work. By achieving a ‘one-step’ removal of impurity ions, deacetalization of IAMP and recovery of KOH, the constant-voltage BME process provided an efficient and environment friendly purification method. The AMP-acid was obtained, and could further produce a series of AMP salts. In addition, the influence of potential difference per three-compartment unit was studies. Process under 6V/Unit and 5.3V/Unit achieved both high separation efficiency and low energy consumption, and the combined use of 5.3V/Unit and 6V/Unit in different stages was anticipated to be the optimum process with optimum energy consumption. [Copyright &y& Elsevier]

• Highly selective production of formic acid from CO 2 is achieved. • The simultaneous encapsulation of two enzymes in ZIF-8 improved reaction efficiency. • ZIF-8 provided a large amount of loaded protein with little damage to enzyme. • Efficient in situ regeneration of NADH was achieved by visible-light irradiation. • The designed nanosystem exhibited excellent operational stability and recyclability. Natural photosynthesis plays an important role in maintaining environmental carbon balance. Taking inspiration from this, we developed a light-driven, enzymatic nanosystem for the highly selective production of formic acid from CO 2. The system combines photocatalytic graphitic carbon nitride (g-C 3 N 4) with two natural enzyme catalysts, carbonic anhydrase (CA) and formate dehydrogenase (FateDH), encapsulated in ZIF-8, a porous metal-organic framework (MOF). Efficient in situ regeneration of reduced nicotinamide adenine dinucleotide (NADH) is realized through visible-light irradiation of g-C 3 N 4 with a suitable redox potential (−0.3 V (NHE)). The introduction of ZIF-8 ensures a large amount of loaded protein with little damage to enzyme activity, and its encapsulation of CA and FateDH shortens the distance between the enzymes. This is conducive to increasing the diffusion of substances during the CO 2 -to-formic acid cascade reaction, thus improving the reaction efficiency. This work is expected to provide new insight into the design and development of highly selective, artificial photosynthesis systems to efficiently convert CO 2 into fuels, chemicals, and other materials. [ABSTRACT FROM AUTHOR]

• Adsorption and diffusion of furfural and water in vinyl-modified PDMS were simulated. • Vinyl-modified PDMS membranes were prepared based on simulation results. • 20.4% and 37.0% improvement in separation factor and furfural flux were achieved. • Experimental results were well interpreted by simulation results. Furfural is an important platform chemical for fine chemicals, which has wide applications and market prospect. However, due to the low furfural concentration in the hydrolysis product of biomass, the separation of furfural from dilute aqueous solution is energy-consuming and challenging. Herein, an efficient-energy technology, pervaporation based on vinyl-modified polydimethylsiloxane (PDMS) membrane, is suggested for the separation of furfural. To investigate the effect of vinyl group on the pervaporation performance of PDMS membrane, a molecular dynamics (MD) simulation via Materials Studio was employed, where vinyl group displays beneficial effects. Thereafter, a series of vinyl-modified PDMS membranes with different vinyl group contents were fabricated by using vinyl triethoxysilane to crosslink PDMS. The membrane exhibits a separation factor of 49.1 and a furfural flux of 737.6 g m−2 h−1 for 3.0 wt% furfural aqueous solution at 65 °C, which are improved by 20.5% and 37.2%, respectively, compared with those of the pristine PDMS membrane and conform with the expectation of MD simulation. This work proves the promising potential of MD simulation and vinyl group modification in preparing pervaporation membrane with high separation performance for furfural. [ABSTRACT FROM AUTHOR]

To reduce the environment pollution from biolubricant synthesis, in this study, we developed a green and efficient strategy for the preparation of octylated branched biolubricant from waste cooking oil (WCO): (1) WCO was first hydrolyzed by a lipase (Candida sp. 99–125) to produce unsaturated fatty acids (UFAs), the latter was subsequently concentrated by urea complexation; (2) Next, we synthesized new esters using the UFAs as substrate via esterification with 2-ethylhexanol employing lipase (Novozym 435) and the new esters products were further epoxidated; (3) After that, the epoxy group was attacked by a low-cost nucleophilic reagent, octanoic acid, to prepare octylated branched biolubricant using an recyclable ionic liquid, [HMIm][PF 6 ], as catalyst. After three recycling times, [HMIm][PF 6 ] remained catalytic activity with a conversion yield of 81.22% and selectivity of 82.10%. The obtained product showed excellent lubricant properties, such as low pour point of −61 °C, high viscosity index of 149 and high thermal-oxidation stability (onset temperature of 326.35 °C and oxidative onset temperature of 312.06 °C). The high frequency reciprocating rig (HFRR) measurement demonstrated that lubrication performance (friction coefficient of 0.09 and wear spot diameter of 203 μm) was much better than that of mineral based lubricant with the same viscosity grade. Therefore, this study provided a critical synthetic strategy for preparing high-performance biolubricants from WCO. Image 1 • An innovative strategy of biolubricant preparation from waste cooking oil was proposed. • Modification on unsaturated sites catalyzed by lipases and ionic liquid. • [HMIm][PF 6 ] remained high stabilization after three recycling times. • Biolubricant exhibited excellent pour point, thermo-oxidative stability and lubrication performance. [ABSTRACT FROM AUTHOR]