Hydrogen-bonded lipase-hydrogel microspheres for esterification application

Comparison of bio-imprinted Aspergillus niger lipase by oleic acid or olive oil to improve esterification performance

To compare the catalytic characteristics of substrate analogs of fatty acids or triglycerides in bio-imprinted lipase, bio-imprinted lipase with oleic acid or olive oil was chosen for investigation. Bioimprinting was combined with resin adsorption immobilization to catalyze the synthesis of sucrose-6-acetate via ester exchange of sucrose with vinyl acetate as a test reaction. Under optimal conditions, the bio-imprinted lipase with oleic acid catalyzed the reaction with an esterification rate of sucrose of 90.6 ± 1.2 % and an esterification of the 6-position hydroxyl group of sucrose of 92.4 ± 1.0 %, while the bio-imprinted immobilized lipase with olive oil catalyzed the reaction with an esterification rate of sucrose of 91.9 ± 1.3 % and an esterification of the 6-position hydroxyl group of sucrose of 93.3 ± 1.2 %, which were similar to the catalytic performances of both bio-imprinted lipases. The secondary structure of bio-imprinted immobilized lipase can be characterized by Fourier transform infrared spectroscopy (FTIR) with a decrease in α-helix and an increase in β-sheet, which suggests the bio-imprinting caused a change in conformations of the lipase protein. Raman spectroscopy results revealed that the structural alterations that occurred in the lipase during the bioimprinting process of oleic acid or olive oil were different. Fluorescence spectroscopy analysis demonstrated that the amino acid microenvironment in the active center of the bio-imprinted lipase became progressively more hydrophobic as the bioimprinting time increased, thereby enhancing the catalytic activity. Structural analysis of the bio-imprinted lipase revealed that the structural alterations in the lipase proteins were different when oleic acid or olive oil were the bio-imprinted molecules. Fatty acids or triglycerides as substrate analogs for the esterification reaction of bio-imprinted lipase can improve catalytic performance and have ideal application prospects.

Sustainable design of hollow macroporous chitin carrier with enhanced loading capacity for high-performance lipase bioreactor

A hollow macroporous chitin carrier (HMCC) was developed as a high-efficiency platform for lipase immobilization, offering superior specific surface area, biocompatibility, and protein affinity. Using a NaOH/urea/water treatment system, chitin was dissolved and processed into HMCC, leveraging its amphiphilic properties to achieve remarkable interfacial performance. Compared to the conventional chitin carrier (~0.34 mg/g), HMCC-OA exhibited a highest 3.39-fold increase in protein loading capacity. Immobilization of Geobacillus thermocatenulatus lipase 2 (GTL2) on HMCC-OA yielded a hydrolytic activity of 145.95 U/mg, surpassing free GTL2 by 1.14-fold. In addition, the HMCC demonstrated exceptional versatility by supporting various commercial lipases while showcasing optimal hydrolytic efficiency with GTL2. Notably, GTL2 bioreactor mitigated thermal inactivation at elevated temperatures (up to 90 °C), retained high activity across short- to medium-chain fatty acids (C4, C8, C10), and maintained significant residual activity (51.79 U/mg) after 10 recycling cycles. These results highlight the innovative design and robust performance of HMCC as a sustainable carrier for lipase bioreactor, enabling enhanced biocatalytic performance demanding thermal stability and interfacial activity.

Rapid Screening of Lipase Inhibitors From Chrysanthemum Based on Ionic Liquid/Chitosan Bifunctionalized Magnetic Multi-Walled Carbon Nanotubes Immobilized Lipase

In this study, a novel ionic liquid/chitosan bifunctionalized magnetic multi-walled carbon nanotubes composite material (m-MWCNTs@CS@IL) was utilized for the first time to immobilize lipase. The immobilized lipase exhibited exceptional stability and reusability, as evidenced by its characteristic properties. A ligand fishing approach utilizing the immobilized lipase was developed to enable rapid screening of lipase inhibitors from Chrysanthemum. Three ligands were successfully screened from Chrysanthemum and then identified as cynaroside, quercitrin, and linarin by ultra-high performance liquid chromatography-tandem mass spectrometry. The IC50 values of these three ligands were 76.77 ± 0.36, 83.01 ± 0.46, and 43.61 ± 0.77 µM, respectively. Furthermore, molecular docking analysis further confirmed the binding of three ligands to specific amino acid residues within the active site of lipase. This work presents a fast and efficient approach for screening lipase inhibitors from intricate natural sources, demonstrating promising prospects in discovering anti-obesity compounds.

Nanomachine Networks: Functional All-Enzyme Hydrogels from Photochemical Cross-Linking of Glucose Oxidase

Enzymes are attractive as catalysts due to their specificity and biocompatibility; however, their use in industrial and biomedical applications is limited by stability. Here, we present a facile approach for enzyme immobilization within "all-enzyme" hydrogels by forming photochemical covalent cross-links between the enzyme glucose oxidase. We demonstrate that the mechanical properties of the enzyme hydrogel can be tuned with enzyme concentration and the data suggests that the dimeric nature of glucose oxidase results in unusual gel formation behavior which suggests a degree of forced induced dimer dissociation and unfolding. We confirm and quantify the enzyme activity of the hydrogel using the Trinder assay and a 1D modeling approach and show that 50% enzymatic activity is retained upon hydrogel formation. These observed effects may be due to the forces experienced by the individual nanoscale enzymes during mesoscale network formation. We have therefore demonstrated that photochemical cross-linking can be readily employed to produce functional all-enzyme glucose oxidase hydrogels with easily tunable mechanical properties and specific catalytic activity. This approach provides enormous potential for producing biocatalytic materials with tunable mechanical properties, responsive biological functionality and high volumetric productivity which may inform the future design of biomedical devices with enhanced sensitivity and activity.

Ultrasound-assisted enzymatic synthesis of cinnamyl acetate by immobilized lipase on ordered mesoporous silicon with CFD simulation and molecular docking analysis

Flavor esters are used in food and cosmetic industries, but sustainable production remains a big challenging. This study proposed the ultrasound-assisted biosynthesis of cinnamyl acetate using self-made immobilized lipase CSL@OMS-C8, with computational fluid dynamics (CFD) and molecular simulations revealing the hydrodynamic properties and lipase-catalytic mechanisms. The results demonstrate that ultrasonication-intensified enzymatic reaction facilitated 96.6 % conversion of cinnamic alcohol, due to the ultrasound-assisted catalytic efficiency of 13.7 mmol/g·min. Molecular docking analysis identifies the lowest binding energy of -3.7 kcal·mol-1 between lipase and vinyl acetate, contributing to the highest conversion rates compared to acetic acid, ethyl acetate. CFD simulation indicates that ultrasonic energy waves promote substrate diffusion and mixing with lower shear stress. The catalytic stability of CSL@OMS-C8 was confirmed by 60.1 % of relative activity after 10-time reuse. This paper theoretically and experimentally studied the ultrasonic-assisted enzymatic synthesis of cinnamyl acetate, showcasing huge potential for sustainable production of flavor esters.

Improved Catalytic Performance of Lipase Within Hydrogel Microspheres Incorporating L/D-Co3O4 Nanoparticles

Lipases have drawn significant attention due to their crucial roles across various industries, including oil processing, food, medicine, and daily chemicals. Nevertheless, their catalytic efficiency is susceptible to fluctuations in external environmental conditions, which remains a major barrier to their broader application. In this research, chiral hydrogel microspheres (HMSs) are developed by incorporating L/D-Co3O4 nanoparticles (NPs) into the synthetic process of HMSs, which are discovered to enhance the catalytic performance of lipases. The improved catalytic activity of lipases is observed to be influenced by the chiral environment of L/D-Co3O4-HMSs. Specifically, when 2 wt.% lipases are encapsulated in L-Co3O4-HMSs containing 10 wt.% L-Co3O4 NPs, their catalytic activity is 2.11 times higher than when encapsulated in D-Co3O4-HMSs, resulting in a 2.62-fold increase in catalytic activity compared to free lipase. Moreover, the L-Lip-HMS3, which contained 2 wt.% lipases and 10 wt.% L-Co3O4 NPs, exhibited superior inhibitory capability over D-Lip-HMS3 in differentiating fibroblast mouse cells into adipocytes, owing to its enhanced catalytic capabilities. This study not only highlights the importance of chirality in improving the catalytic performance of natural enzymes but also provides a new perspective on developing catalytic systems that can endow natural enzymes with higher catalytic performances.

Biosynthesis of Feruloyl Glycerol from Ferulic Acid and Glycerol Through a Two-Enzyme Cascade Reaction

Feruloyl glycerol (FG) has a variety of biological activities, but the green synthesis methods of FG remain rare. In this study, FG was prepared by a cascade reaction catalyzed by 4-coumarate coenzyme A ligase (4CL) and hydroxycinnamoyl acyltransferase 4 (HCT4). The cascade reaction carried out at solvent water and room temperature is more convenient and greener. Firstly, the product derived from the cascade reaction was characterized by TLC, HPLC, FTIR, and ESI-MS. The results showed that the product was FG. Secondly, the effects of temperature, pH, enzyme ratio, Mg2+ concentration, and CoA concentration on the cascade reaction were investigated. Consequently, the highest reaction rate was obtained at 30 °C, pH 6, an enzyme ratio of 1:3, and Mg2+ concentration of 5 mM. Finally, semi-preparative scale synthesis for FG was conducted. The production of FG reached 35.1 mM at 24 h with the FG conversion of 70.18%. In a word, a novel idea for the efficient and green synthesis of FG was proposed, which had great potential for industrial application.

Enzyme-mediated multifunctional self-healing lysozyme hydrogel for synergistic treatment of chronic diabetic wounds

Self-healing hydrogels have attracted significant attention in chronic diabetic wound healing due to their potential to minimize the risk of secondary infections caused by joint movement or dressing rupture. Herein, a multifunctional self-healing hydrogel mediated utilizing an enzyme-triggered cascade reaction based on dynamic imine bonds was designed. The hydrogel employs three enzymes: lysozyme (LYZ), glucose oxidase (GOx), and catalase (CAT), as building blocks. GOx catalyzes the conversion of glucose and 1-thio-β-d-glucose (β-GlcSH) into hydrogen peroxide (H2O2), gluconic acid (GA), and hydrogen sulfide (H2S). Subsequently, CAT eliminates H2O2, protecting the imine bonds from oxidative damage. The acidic environment created by GA decreases the pH and regulates the crosslinking density of imine bonds, enhancing the self-healing capability and porosity of the hydrogel. This feature enables the sustained release of the drug rosuvastatin calcium (RCa) to promote endothelial cell migration and vascular regeneration. Combined with the antioxidative and anti-inflammatory effects of released H2S gas and the antibacterial properties of lysozyme, this hydrogel exhibits promising therapeutic efficacy for the synergistic treatment of chronic diabetic wounds.

Ionic liquid supported hydrogel-lipase biocatalytic systems in asymmetric synthesis of enantiomerically pure S-ibuprofen

Novel hydrogel biocatalysts with immobilized lipase, stabilized by ionic liquids (ILs) of different hydrophobicity, were synthesized and evaluated. Variations of the time of immobilization and ratio of substrates during hydrogel synthesis were considered to obtain the most stable biocatalyst with the highest activity. Physicochemical characterization proved the success of the hydrogel synthesis and enzyme deposition on the surface of the support. Nevertheless, the key objective was to produce a biocatalyst for further application in ibuprofen methyl ester resolution, with the aim of obtaining an enantiomerically pure product. The hydrogel biocatalysts obtained in the presence of 5 wt% ILs after 8 h of immobilization achieved the highest activity recovery of 62 %. After 10 reaction cycles, enzymatic activity was still above 60 %, and the negative effect of pH and temperature on the activity of immobilized lipase was much lower than in the case of the free enzyme. After application of the catalyst in the resolution of ibuprofen methyl ester, the enantiomeric excess and conversion rate of the process were obtained for the dynamic kinetic resolution in isooctane. A conversion rate of 95 % was achieved due to the stabilization of the biocatalyst with IL and its resulting high catalytic activity. The study thus provides the pharmaceutical industry with a new potential approach with a strong scientific foundation.

Rapid screening of xanthine oxidase inhibitors from Ligusticum wallichii by using xanthine oxidase functionalized magnetic metal-organic framework

In this study, xanthine oxidase was immobilized for the first time using a novel magnetic metal-organic framework material (Fe3O4-SiO2-NH2@MnO2@ZIF-8-NH2). A ligand fishing method was established to rapidly screen XOD inhibitors from Ligusticum wallichii based on the immobilized XOD. Characterization and properties of the immobilized enzyme revealed its excellent stability and reusability. A ligand was screened from Ligusticum wallichii and identified as ligustilide by ultra-high performance liquid chromatography tandem mass spectrometry. The IC50 value of ligustilide was determined to be 27.70 ± 0.13 μM through in vitro inhibition testing. Furthermore, molecular docking verified that ligustilide could bind to amino acid residues at the active site of XOD. This study provides a rapid and effective method for the preliminary screening of XOD inhibitors from complex natural products and has great potential for further discovery of anti-hyperuricemic compounds.

Pros and Cons in Various Immobilization Techniques and Carriers for Enzymes

In recent years, enzyme immobilization technology has been developed, and studies on immobilized enzyme materials have become very prominent. With the immobilization technique, enzymes and compatible carrier materials are combined or enzyme crystals/aggregates are used in a carrier-free fashion, by physical, chemical, or biochemical methods. As a kind of biocatalyst, immobilized enzymes can catalyze certain chemical reactions with high selectivity and high efficiency under relatively mild reaction conditions and eliminate pollution to the environment. Considering the current status and applications of immobilized enzyme technology and materials emerging in the last 5 years, this mini-review introduces the advantages and disadvantages of various enzyme immobilization techniques with carriers as well as the pros and cons of different materials for immobilization. The future prospects of immobilization technology and carrier materials are outlined, aiming to provide a reference for further research and applications of sustainable technology.

Research Progress on Injectable Microspheres as New Strategies for the Treatment of Osteoarthritis Through Promotion of Cartilage Repair

Osteoarthritis (OA) is a degenerative disease caused by a variety of factors with joint pain as the main symptom, including fibrosis, chapping, ulcers, and loss of cartilage. Traditional treatment can only delay the progression of OA, and classical delivery system have many side effects. In recent years, microspheres have shown great application prospects in the field of OA treatment. Microspheres can support cells, reproduce the natural tissue microenvironment in vitro and in vivo, and are an efficient delivery system for the release of drugs or biological agents, which can promote cell proliferation, migration, and differentiation. Thus, they have been widely used in cartilage repair and regeneration. In this review, preparation processes, basic materials, and functional characteristics of various microspheres commonly used in OA treatment are systematically reviewed. Then it is introduced surface modification strategies that can improve the biological properties of microspheres and discussed a series of applications of microsphere functionalized scaffolds in OA treatment. Finally, based on bibliometrics research, the research development, future potential, and possible research hotspots of microspheres in the field of OA therapy is systematically and dynamically evaluated. The comprehensive and systematic review will bring new understanding to the field of microsphere treatment of OA.

Controllable enzymatic hydrolysis in reverse Janus emulsion microreactors

HYPOTHESIS

The key feature of living cells is multicompartmentalization for enzymatic reactions. Artificial cell-like multicompartments with micro domains are appealing to mimic the biological counterparts. In addition, establishing a sustainable, efficient, and controllable reaction system for enzymatic hydrolysis is imperative for the production of natural fatty acids from animal and plant-based fats.

EXPERIMENTS

Reverse Janus emulsion microreactors, i.e. (W1 + W2)/O, is constructed through directly using natural fats as continuous phase and aqueous two-phase solutions (ATPS) as inner phases. Enzyme is confined in the compartmented aqueous droplets dominated by the salt of Na2SO4 and polyethylene glycol (PEG). Enzyme catalyzed ester hydrolysis employed as a model reaction is performed under the conditions of agitation-free and mild temperature. Regulation of reaction kinetics is investigated by diverse droplet topology, composition of inner ATPS, and on-demand emulsification.

FINDINGS

Excellent enzymatic activity toward hydrolysis of plant and animal oils achieves 88.5 % conversion after 3 h. Compartmented micro domains contribute to condense and organize the enzymes spatially. Timely removal of the products away from reaction sites of oil/water interface "pushed" the reaction forward. Distribution and transfer of enzyme in two aqueous lobes provide extra freedom in the regulation of hydrolysis kinetics, with equilibrium conversion controlled freely from 14.5 % to 88.5 %. Reversible "open" and "shut" of hydrolysis is acheived by on-demand emulsification and spontaneous demulsification. This paper paves the way to advancing progress in compartmentalized emulsion as a sustainable and high-efficiency platform for biocatalytic applications.

Lipase in-situ immobilized in covalent organic framework: Enzymatic properties and application in the preparation of 1, 3-dioleoyl-2-palmitoylglycerol

In this study, the critical importance of designing an appropriate immobilized carrier and method for free lipase to ensure exceptional biological catalytic activity and stability was emphasized. Covalent organic frameworks (COF-1) were synthesized as a novel porous carrier with an azine structure (-CN-NC-) through the condensation of hydrazine hydrate and benzene-1,3,5-tricarbaldehyde at room temperature. Simultaneously, Rhizomucor miehei lipase (RML) was immobilized within the COF-1 carrier using an in-situ aqueous phase method. Characterization of the carrier and RML@COF-1 and evaluation of the lipase properties of RML and RML@COF-1 through p-Nitrophenyl palmitate hydrolysis were conducted. Additionally, application in the synthesis of 1, 3-dioleoyl-2-palmitoylglycerol (OPO) was explored. The results showed that RML@COF-1 exhibited a high enzymatic loading of 285.4 mg/g. Under 60℃ conditions, the activity of RML@COF-1 was 2.31 times higher than that of free RML, and RML@COF-1 retained 77.25% of its original activity after 10 cycles of repeated use, indicating its excellent thermal stability and repeatability. Under the optimal conditions (10%, 1:8 PPP/OA, 45℃, 5 h), the yield of OPO reached 47.35%, showcasing the promising application prospects of the novel immobilized enzyme synthesized via in-situ aqueous phase synthesis for OPO preparation.

Enzymatic interfacial conversion of acylglycerols in Pickering emulsions stabilized by hydrogel microparticles

HYPOTHESIS

A critical challenge in the enzymatic conversion of acylglycerols is the limited exposure of the enzyme dissolved in the aqueous solution to the hydrophobic substrate in the oil phase. Positioning the enzyme in a microenvironment with balanced hydrophobicity and hydrophilicity in Pickering emulsion will facilitate the acylglycerol-catalyzing reactions at the interface between the oil and liquid phases.

EXPERIMENTS

In this work, to overcome the challenge of biphasic catalysis, we report a method to immobilize enzymes in polyethylene glycol (PEG)-based hydrogel microparticles (HMPs) at the interface between the oil and water phases in Pickering emulsion to promote the enzymatic conversion of acylglycerols.

FINDINGS

3 wt% of HMPs can stabilize the oil-in-water Pickering emulsion for at least 14 days and increase the viscosity of emulsions. Lipase-HMP conjugates showed significantly higher hydrolytic activity in Pickering emulsion; HMP-immobilized lipase SMG1 showed an activity about three times that of free lipase SMG1. Co-immobilization of a lipase and a fatty acid photodecarboxylase from Chlorella variabilis (CvFAP) in Pickering emulsion enables light-driven cascade conversion of triacylglycerols to hydrocarbons, transforming waste oil to renewable biofuels in a green and sustainable approach. HMPs stabilize the Pickering emulsion and promote interfacial biocatalysis in converting acylglycerols to renewable biofuels.

Pickering emulsion biocatalysis: Bridging interfacial design with enzymatic reactions

Non-homogeneous enzyme-catalyzed systems are more widely used than homogeneous systems. Distinguished from the conventional biphasic approach, Pickering emulsion stabilized by ultrafine solid particles opens up an innovative platform for biocatalysis. Their vast specific surface area significantly enhances enzyme-substrate interactions, dramatically increasing catalytic efficiency. This review comprehensively explores various aspects of Pickering emulsion biocatalysis, provides insights into the multiple types and mechanisms of its catalysis, and offers strategies for material design, enzyme immobilization, emulsion formation control, and reactor design. Characterization methods are summarized for the determination of drop size, emulsion type, interface morphology, and emulsion potential. Furthermore, recent reports on the design of stimuli-responsive reaction systems are reviewed, enabling the simple control of demulsification. Moreover, the review explores applications of Pickering emulsion in single-step, cascade, and continuous flow reactions and outlines the challenges and future directions for the field. Overall, we provide a review focusing on Pickering emulsions catalysis, which can draw the attention of researchers in the field of catalytic system design, further empowering next-generation bioprocessing.

Recent applications and future prospects of magnetic biocatalysts

Magnetic biocatalysts combine magnetic properties with the catalytic activity of enzymes, achieving easy recovery and reuse in biotechnological processes. Lipases immobilized by magnetic nanoparticles dominate. This review covers an advanced bibliometric analysis and an overview of the area, elucidating research advances. Using WoS, 34,949 publications were analyzed and refined to 450. The prominent journals, countries, institutions, and authors that published the most were identified. The most cited articles showed research hotspots. The analysis of the themes and keywords identified five clusters and showed that the main field of research is associated with obtaining biofuels derived from different types of sustainable vegetable oils. The overview of magnetic biocatalysts showed that these materials are also employed in biosensors, photothermal therapy, environmental remediation, and medical applications. The industry shows a significant interest, with the number of patents increasing. Future studies should focus on immobilizing new lipases in unique materials with magnetic profiles, aiming to improve the efficiency for various biotechnological applications.

Construction of molecular enrichment accelerators via assembly of enzyme surface grafted polymer and cyclodextrin achieving rapid and stable ester catalysis for biodiesel synthesis

Efficient and stable catalysis has always been the core concept of enzyme catalysis in industrial processes for manufacturing. Here, we constructed molecular enrichment accelerators to synergistically enhance enzyme activity and stability by assembling enzyme surface grafted polymer and cyclodextrin. At 40 °C, the enzyme activity of CalB-PNIPAM212/β-CD was 2.9 times that of CalB-PNIPAM212. The enzyme activity of CalB-PNIPAM428/γ-CD had reached 1.61 times that of CalB. At the same time, the stability of CalB-PNIPAM212/β-CD and CalB-PNIPAM428/γ-CD are slightly better than that of CalB under high temperature, organic solution and extreme pH conditions. The synergistic increase in activity and stability of the lipase-polymer assembly was achieved due to the structure of assembly, in which the role of cyclodextrin could enrich substrate affecting molecular diffusion. In addition, the lipase-polymer assembly proved to be an efficient catalyst for biodiesel synthesis, with a biodiesel conversion 1.4 times that of CalB at 60 °C. Therefore, this simple and low-cost lipase-polymer assembly provides new possibilities for the construction of high-efficiency industrial biocatalytic catalysts.

A novel multi-scale pressure sensing hydrogel for monitoring the physiological signals of long-term bedridden patients

For long-term bedridden patients who need to wear diapers, the timely replacement of diapers is very important to ensure their quality of life. Therefore, it is urgent to develop a pressure sensor that can monitor the physiological conditions of patients in real time. Inspired by the multi-scale network structure of the multi-fiber protein in the muscle, a multi-scale hydrogel as a pressure sensor was prepared by introducing micron-scale hydrogel microspheres as physical crosslinking agents. Compared with the traditional polyacrylamide hydrogel (0.17 MPa of compressive strength), the multi-scale hydrogel showed a higher compressive strength of up to 1.37 MPa. Meanwhile, the hydrogel exhibited better pressure sensitivity (0.59 kPa-1) than the existing hydrogels (0.27-0.40 kPa-1). The sensor prepared by this hydrogel could monitor the patient's physiological condition (urine outflow and urinary filling) in real time through the conductivity response to ion concentration and pressure, and then transmit the signal to the caregivers in time to avoid skin damage. This multi-scale hydrogel provided a great convenience for the physiological monitoring of long-term bedridden patients by acting as a pressure sensor.

Short Peptides for Hydrolase Supramolecular Mimicry and Their Potential Applications

Hydrolases are enzymes that have found numerous applications in various industrial sectors spanning from pharmaceuticals to foodstuff and beverages, consumers' products such as detergents and personal care, textiles, and even for biodiesel production and environmental bioremediation. Self-assembling and gelling short peptides have been designed for their mimicry so that their supramolecular organization leads to the creation of hydrophobic pockets for catalysis to occur. Catalytic gels of this kind can also find numerous industrial applications to address important global challenges of our time. This concise review focuses on the last 5 years of progress in this fast-paced, popular field of research with an eye towards the future.

Effect of Oil Polarity on the Protein Adsorption at Oil-Water Interfaces

Protein adsorption at oil-water interfaces has received much attention in applications of food emulsion and biocatalysis. The protein activity is influenced by the protein orientation and conformation. The oil polarity is expected to influence the orientation and conformation of adsorbed proteins by modulating intermolecular interactions. Hence, it is possible to tune the protein emulsion stability and activity by varying the oil polarity. Martini v3.0-based coarse-grained molecular dynamics (CGMD) simulations were employed to investigate the effect of oil polarity on the orientation and conformation of hydrophobin (HFBI) and Candida antarctica lipase B (CALB) adsorbed at triolein-water, hexadecane-water, and octanol-water interfaces for the first time. The protein adsorption orientation was predicted through the hydrophobic dipole, indicating that protein adsorption exists in preferred orientations at hydrophobic oil interfaces. The conformation of the adsorbed HFBI is well conserved, whereas relatively larger conformational changes occur during the CALB adsorption as the oil hydrophobicity increases. Comparisons on the adsorption interaction energy of proteins with oils confirm the relationship between the oil polarity and the interaction strength of proteins with oils. In addition, CGMD simulations allow longer time scale simulations of the behaviors of protein adsorption at oil-water interfaces.

Preparation strategy of hydrogel microsphere and its application in skin repair

In recent years, hydrogel microsphere has attracted much attention due to its great potential in the field of skin repair. This paper reviewed the recent progress in the preparation strategy of hydrogel microsphere and its application in skin repair. In this review, several preparation methods of hydrogel microsphere were summarized in detail. In addition, the related research progress of hydrogel microspheres for skin repair was reviewed, and focused on the application of bioactive microspheres, antibacterial microspheres, hemostatic microspheres, and hydrogel microspheres as delivery platforms (hydrogel microspheres as a microcarrier of drugs, bioactive factors, or cells) in the field of skin repair. Finally, the limitations and future prospects of the development of hydrogel microspheres and its application in the field of skin repair were presented. It is hoped that this review can provide a valuable reference for the development of the preparation strategy of hydrogel microspheres and promote the application of hydrogel microspheres in skin repair.

Modulating the performance of lipase-hydrogel microspheres in a "micro water environment"

In our previous work, we successfully stimulated lipase activity in an anhydrous reaction system using porous polyacrylamide hydrogel microsphere (PPAHM) as a carrier of lipase and free water. However, the effect of the existence state and content of water in lipase-porous polyacrylamide hydrogel microsphere (L-PPAHM) on the interfacial activation remained unclear. In this work, L-PPAHM with different water contents were obtained by water mist rehydration and were used to catalyze the synthesis of conjugated linoleic acid ethyl ester (CLA-EE). The results revealed that there were three existence states of water in L-PPAHM: bound water, semi-bound water and free water, and free water provided the "micro water environment" for the interfacial activation of lipase. The reusability of L-PPAHM with different water contents showed that the activity and stability of L-PPAHM could be achieved by varying the water content of L-PPAHM. The proportion of free water in L-PPAHM increased, and the activity of L-PPAHM increased, but the strength of hydrogen bond interaction between PPAHM and lipase weakened, resulting in the decrease of stability. L-PPAHM with 2/3 of water absorption could ensure sufficient immobilized lipase activity and stability, and its water absorption property could reduce the free water generated during esterification, thus increasing the yield of CLA-EE.

Performance of Microenvironment-induced Lipase Immobilization on diversify Surface of Magnetic Particle

The orientation of the enzyme molecular on the interface of the carrier affects its activity. Therefore, it is very important to controllably induce the orientation of the enzyme on the surface to improve the performance of the immobilized enzyme. Magnetic nanoparticles were used to construct microenvironments with the different surface hydrophobicity and charge characteristics by controlled modification, and those particles with various microenvironments were further used to study their interaction with the lipase. The amount and activity of immobilized enzyme on different magnetic nanoparticles surfaces were studied by physical adsorption and covalent binding. Through the enzyme surface and particle surface characteristics analysis, the possible preferred orientation of enzyme and enzyme conformation on different surfaces were inferred, which well explained the effect of surface induction on enzyme loading and activity. The methods of surface microenvironment regulation and the strategy of controllable induction of enzyme orientation adopted in this study are enlightening for the rational design of immobilized enzyme methods.

Construction of a Microbial Consortium for the De Novo Synthesis of Butyl Butyrate from Renewable Resources

Butyl butyrate has shown wide applications in food, cosmetic, and biofuel sectors. Currently, biosynthesis of butyl butyrate still requires exogenous addition of precursors and lipase, which increases the production cost and limits further large-scale development. In this study, a microbial consortium was first designed to realize direct butyl butyrate production from lignocellulose. The highest butyl butyrate concentration of 34.42 g/L was detected in the solvent phase from 60 g/L glucose using a microbial coculture system composed of Clostridium acetobutylicum NJ4 and Clostridium tyrobutyricum LD with the elimination of butyric acid supplementation. Meanwhile, 13.52 g/L butyl butyrate was synthesized from 60 g/L glucose using a microbial consortium composed of three strains including strain NJ4, strain LD, and Escherichia coli BL21- pET-29a(+)-LE without the addition of any exogenous precursors and lipase. In addition, 2.94 g/L butyl butyrate could be directly produced from 60 g/L microcrystalline cellulose when Trichoderma asperellum was added to the above-mentioned three-strain microbial consortium. This four-strain microbial consortium represents the first study regarding the direct butyl butyrate production from lignocellulose without the supplementation of exogenous precursors and lipase, which may be extended to the biosynthesis of other short-chain esters, such as ethyl acetate and butyl lactate.

Novel Lipase Reactor based on Discontinuous Interfaces in Hydrogel-Organogel Hybrid Gel: A Preliminary Exploration

According to the "interfacial activation" mechanism, constructing a sufficient interface is the key strategy for lipase-catalytic system designing. Based on the "infinite interface in finite three-dimensional space" logic, in the current study, poly(N,N-dimethylacrylamide) (PDMA)-polybutyl methacrylate (PBMA) hybrid gels were prepared by a two-step crosslinking strategy, subsequently constructed as lipase-interfacial catalytic systems. The results confirm that the PDMA-PBMA hybrid gels with "networks in pores" structures could swell both the aqueous phase and organic phase. The balance between water swelling and isooctane swelling, hybrid gel space (height control), and the lipase entry manner significantly affect the interface construction and consequently the catalytic efficiency. The enzyme-substrate contact rate affected by swelling leads to three catalytic stages. Considering the spatial barrier and distribution of lipases, a potential high-performance lipase reactor can be assembled from small-size, lamellar-like, and porous hybrid gels. The reactors also show good time storage and low temperature tolerance.

Lipase Catalyzed Transesterification of Model Long-Chain Molecules in Double-Shell Cellulose-Coated Oil-in-Water Emulsion Particles as Microbioreactors

Lipase-catalyzed transesterification is prevalent in industrial production and is an effective alternative to chemical catalysis. However, due to lipases' unique structure, the reaction requires a biphasic system, which suffers from a low reaction efficiency caused by a limited interfacial area. The use of emulsion particles was found to be an effective way to increase the surface area and activity. This research focuses on cellulose as a natural surfactant for oil-in-water emulsions and evaluates the ability of lipase, introduced into the emulsion's aqueous phase, to integrate with the emulsion microparticles and catalyze the transesterification reaction of high molecular weight esters dissolved in the particles' cores. Cellulose-coated emulsion particles' morphology was investigated by light, fluorescence and cryogenic scanning electron microscopy, which reveal the complex emulsion structure. Lipase activity was evaluated by measuring the hydrolysis of emulsified p-nitrophenyl dodecanoate and by the transesterification of emulsified methyl laurate and oleyl alcohol dissolved in decane. Both experiments demonstrated that lipase introduced in the aqueous medium can penetrate the emulsion particles, localize at the inner oil core interface and perform effective catalysis. Furthermore, in this system, lipase successfully catalyzed a transesterification reaction rather than hydrolysis, despite the dominant presence of water.

Tailoring Lignin-Based Spherical Particles as a Support for Lipase Immobilization

Lignin-based spherical particles have recently gained popularity due to their characteristic and the usage of biopolymeric material. In this study, lignin-based spherical particles were prepared using choline chloride at different pH values, ranging from 2 to 10. Their dispersive, microstructural, and physicochemical properties were studied by a variety of techniques, including scanning electron microscopy, Fourier transform infrared spectroscopy, and zeta potential analysis. The best results were obtained for the particles prepared at pH 5 and 7, which had a spherical shape without a tendency to form aggregates and agglomerates. The lignin-based spherical particles were used for the immobilization of lipase, a model enzyme capable of catalyzing a wide range of transformations. It was shown that the highest relative activity of immobilized lipase was obtained after 24 h of immobilization at 30 °C and pH 7, using 100 mg of the support. Moreover, the immobilized lipase exhibited enhanced stability under harsh process conditions, and demonstrated high reusability, up to 87% after 10 cycles, depending on the support used. In the future, the described approach to enzyme immobilization based on lignin spheres may play a significant role in the catalytic synthesis of organic and fine chemicals, with high utility value.

Lipase-polydopamine magnetic hydrogel microspheres for the synthesis of octenyl succinic anhydride starch

Octenyl succinic anhydride (OSA) starch is an important edible additive in the food field, and its synthesis method has attracted much attention. Lipase as a biocatalyst can improve the synthesis efficiency of OSA starch, and significantly inhibit the occurrence of side reactions. However, free lipase has not been widely applied in the synthesis of OSA starch due to the difficulty of separation from starch and poor reusability. In this work, a promising strategy for the synthesis of OSA starch catalyzed by lipase immobilized on polydopamine magnetic hydrogel microspheres (PMHM) is reported. The prepared lipase-polydopamine magnetic hydrogel microspheres (L-PMHM) can be uniformly dispersed in starch slurry, which is conducive to the full contact between lipase and starch. L-PMHM (Km =2.6276 μmol/mL) exhibits better affinity to the substrate than free lipase (Km = 3.4301 μmol/mL). Compared with the OSA starch catalyzed by free lipase (DS = 0.0176), the degree of substitution of OSA starch catalyzed by L-PMHM is up to 0.0277 in a short reaction time. In cyclic catalysis, L-PHMM can remain about 48 % of their original activity after 20 reuses and can be quickly separated from the product. These results suggest that L-PMHM has great potential as a biocatalyst for the efficient synthesis of OSA starch.

Synthesis of lipase-hydrogel microspheres and their application in deacidification of high-acid rice bran oil

The main challenge of rice bran oil (RBO) as a highly nutritional edible oil is the high content of free fatty acids.