Immobilization of lipase on silica nanoparticles by adsorption followed by glutaraldehyde cross-linking

Pickering emulsions stabilized by chitosan-zein-lipase particles for interfacial catalysis

Lipase is widely used in the food industry, but its catalytic efficiency is limited by the insufficient enzyme-substrate contact. To address this issue, chitosan-zein complex particles immobilized lipase (CZPs-lipase) and the corresponding Pickering emulsion catalytic system (PEC) were fabricated. The results showed that the incorporation of zein increased the three-phase contact angle of the particles and decreased the particle size, facilitating lipase immobilization. However, the reduced ζ-potential of the particles was unfavorable for the lipase immobilization by electrostatic adsorption. As a compromise, the maximum immobilized lipase activity was obtained at a chitosan:zein mass ratio of 1:2 (CZPs1:2-lipase). In addition, the PEC stabilized by CZPs-lipase had a significantly (P < 0.05) smaller particle size than that stabilized by chitosan-lipase particles. Consequently, after 120 min of reaction, the hydrolysis rate of p-nitrophenol palmitate in the PEC stabilized by CZPs1:2-lipase was 1.66 and 3.67 times that of the free lipase emulsion and the free lipase biphasic catalytic system, respectively. Meanwhile, after 180 min of reaction, the hydrolysis rate of corn oil and soybean oil in the PEC reached 75.68 ± 1.85 % and 96.27 ± 2.26 %, respectively, significantly (P < 0.05) higher than that in the free lipase emulsion. After five cycles, the relative hydrolysis rate remained at approximately 85 %. This efficient and PEC has considerable potential for applications in the food industry.

Novel Immobilized Enzyme System Using Hydrophobic Dendritic Mesoporous Silica Nanospheres for Efficient Flavor Ester Production

Enzymatic synthesis of flavor esters is widely used in the food and flavor industries, but challenges remain in improving the catalytic efficiency and stability of biocatalysts. This study evaluates the performance of a novel biocatalyst, CALB@DMSN-C8, formed by immobilizing Candida antarctica lipase B (CALB) on hydrophobic dendritic mesoporous silica nanospheres (DMSN-C8), for synthesizing flavor esters. The CALB@DMSN-C8 catalyst achieves a caproic acid conversion rate of 98.5 ± 0.5% in just 30 min and demonstrates outstanding thermal stability, retaining a high conversion efficiency over 20 reuse cycles. To our knowledge, this study represents the most efficient synthesis of flavor esters, including ethyl valerate, ethyl caproate, ethyl heptanoate, and ethyl caprylate, compared to studies in the existing literature. Analysis of aroma characteristics and molecular docking simulations revealed the typical flavor profiles and synthesis mechanisms of various mellow esters. This study develops an innovative strategy by using self-made immobilized lipases to catalyze the production of flavor esters with potential applications in food and cosmetics.

Study of the biochemical and kinetic properties of Candida antarctica lipase immobilized on magnetized poly(styrene-co-ethylene glycol dimethacrylate) and the development of a mathematical model for emollient ester synthesis

The present study aimed to develop a biocatalyst through the immobilization of Candida antarctica lipase B (CALB) via physical adsorption onto magnetized poly(styrene-co-ethylene glycol dimethacrylate) (STY-EGDMA-M). Biochemical property characterization, apparent kinetic parameter determination, and thermal stability assessment were conducted using a methodology developed based on the hydrolysis of the ester methyl butyrate. The results demonstrated that immobilization expanded the enzyme's optimal pH range, with the best performance observed at pH 7.5 and 8, reaching approximately 730 U g⁻1. Additionally, increasing the temperature to 55°C led to an enhancement in the biocatalyst's hydrolytic activity, achieving a maximum of 916.24 U g⁻1. Kinetic parameter analysis yielded values of 321.38 ± 6.31 mM for Km and 4322.46± 75.73 U g⁻1 for Vmax. Thermal stability tests were conducted at 55°C, revealing that 83% of the biocatalyst's initial activity was retained after 24 h of exposure. Furthermore, the biocatalyst's performance in the synthesis of emollient esters (butyl oleate, 2-ethylhexyl oleate, and octyl oleate) via solvent-free esterification was evaluated. The synthesis of emollient esters demonstrated conversions exceeding 55% for octyl oleate and 2-ethylhexyl oleate at 50 and 55°C, whereas the maximum conversion for butyl oleate was 42% at 55°C. Among the bioprocesses evaluated, the synthesis of octyl oleate was selected for kinetic modeling using the ping-pong bi-bi mechanism, with five different parameter arrangements constructed. The model with the lowest corrected Akaike information criterion (AICC = 129.649) was selected. The findings obtained in this work open new avenues for biotechnological applications, reinforcing the relevance of the biocatalyst as a promising tool for industrial processes and scientific research. Additionally, this study provides an alternative methodology for the biochemical characterization of immobilized lipases and employs mathematical modeling to enhance the kinetic understanding of enzymatic reactions conducted at different temperatures.

Advancements in lipase immobilization: Enhancing enzyme efficiency with nanomaterials for industrial applications

One of the most widely utilized enzymes, lipase is crucial to many biotechnological and industrial processes, including those in the biodiesel, food, paper, and oleochemical sectors, as well as in applications related to medicine. However, its use is highly costly and challenging due to its instability and aqueous solubility. Immobilization is a commonly employed way to enhance lipase activity, and it has proven to be a successful approach. In comparison to free lipase, immobilized lipase on nanomaterials (NMs) as demonstrated superior properties, including greater pH and temperature stability, a longer stable duration, and the ability to be recycled. However, under specific circumstances, protein loading is comparatively decreased and lipase immobilization on NMs might also occasionally result in activity loss. The processes of immobilization, the kind of NM's being employed, and the physicochemical characteristics of the NMs (such as particle size, aggregation behaviour, NM dimension, and kind of coupling/modifying agents being used) all affect the overall performance of immobilized lipase on NM's. In recent years, innovative nanostructured forms such nanoflowers, carbon nanotubes, nanofibers, and metal-organic frameworks (MOFs) have been researched for numerous applications along with classic nanomaterials like nano silicon, magnetic nanoparticles, and nanometal particles. To use immobilized lipase on/in nanomaterials for large-scale industrial applications, a few issues still need to be resolved. This study addresses the current advancements and the impact of NMs on lipase immobilization and activity based on the unique characteristics of lipase and NM's.

Recent Advances in Enzymatic Biofuel Cells to Power Up Wearable and Implantable Biosensors

Enzymatic biofuel cells (EBFCs) have emerged as a transformative solution in the quest for sustainable energy, offering a biocatalyst-driven alternative for powering wearable and implantable self-powered biosensors. These systems harness renewable enzyme activity under mild conditions, positioning them as ideal candidates for next-generation biosensing applications. Despite their promise, their practical deployment is limited by challenges such as low power density, restricted operational lifespan, and miniaturization complexities. This review provides an in-depth exploration of the evolving landscape of EBFC technology, beginning with fundamental principles and the latest developments in electron transfer mechanisms. A critical assessment of enzyme immobilization techniques, including physical adsorption, covalent binding, entrapment, and cross-linking, underscores the importance of optimizing enzyme stability and catalytic activity for enhanced bioelectrode performance. Additionally, we examine advanced bioelectrode materials, focusing on the role of nanostructures such as carbon-based nanomaterials, noble metals, conducting polymers, and metal-organic frameworks in improving electron transfer and boosting biosensor efficiency. Also, this review includes case studies of EBFCs in wearable self-powered biosensors, with particular attention to the real-time monitoring of neurotransmitters, glucose, lactate, and ethanol through sweat analysis, as well as their integration into implantable devices for continuous healthcare monitoring. Moreover, a dedicated discussion on challenges and trends highlights key limitations, including durability, power management, and scalability, while presenting innovative approaches to address these barriers. By addressing both technical and biological constraints, EBFCs hold the potential to revolutionize biomedical diagnostics and environmental monitoring, paving the way for highly efficient, autonomous biosensing platforms.

Biocatalytic synthesis of L-ascorbyl palmitate using oleic acid imprinted Aspergillus niger lipase immobilized on resin

In order to improve the esterification efficiency of the enzymatic synthesis of l-ascorbic acid palmitate, the substrate analogue imprinting of the Aspergillus niger lipase-catalyzed esterification process was studied. Oleic acid was selected as the imprinting molecule, oleic acid imprinting immobilized lipase was prepared at pH 8.0, 0.1 g oleic acid, 1.5 mL of 95 % ethanol, and 0.1 g Tween-20. Through solubilization and supersaturation of Vitamin C, the reaction concentration of Vitamin C reached 5.00 % (m/v) in dioxane with 93.99 % esterification rate and 110.72 g/L of product concentration. Moreover, the Vitamin C reaction concentration can reach 8.00 % by using staged substrate feeding, and the esterification rate and product concentration of esterification after 28 h was 156.34 g/L and 82.96 %. Besides, the imprinting-induced conformational changes in enzyme proteins was characterized by fluorescence and infrared spectroscopy. This method provides a pathway for enzymatic production of l-ascorbic acid palmitate.

Improved catalytic stability of immobilized Candida antarctica lipase B on macroporous resin with organic polymer coating for biodiesel production

Lipase is one of the most widely studied and applied biocatalysts. Due to the high enzyme leakage rate of the immobilization method of physical adsorption, we propose a new lipase immobilization method, based on the combination of macroporous resin adsorption and organic polymer coating. The immobilized Candida antarctica lipase B (CALB@resin-CAB) was prepared by combining the macroporous resin adsorption with cellulose acetate butyrate coating, and its structure was characterized by various analytic methods. Immobilized lipase was applied for biodiesel production using acidified palm oil as the starting material, the conversion rate achieved as high as 98.5% in two steps. Furthermore, the immobilized lipase displayed satisfactory stability and reusability in biodiesel production. When the aforementioned reaction was carried out in a continuous flow packed bed system, the yield of biodiesel was 94.8% and space-time yield was 2.88 g/(mL∙h). The immobilized lipase CALB@resin-CAB showed high catalytic activity and stability, which has good potential for industrial application in the field of oil processing.

Evaluation of cross-linkers in the design of immobilized multi isomerase cascade for the preparation of rare sugars

The cascade of sugar isomerases is one of the most practical methods for producing rare sugars, and enzyme immobilization endows it with high economic efficiency, operational convenience and reusability. However, the most employed cross-linker glutaraldehyde (GA) has the disadvantages of enzyme deactivation and limitation of substrate binding. Herein, three compounds, glyoxal, GA, and 2,5-furandicarboxaldehyde (DFF) were evaluated within a previously developed cascade comprising ribose-5-phosphate isomerase and D-tagatose-3-epimerase to prepare D-ribulose form D-xylose. Analyses of surface morphology, element and chemical bond revealed that all compounds effectively cross-linked the isomerases. High concentration of the cross-linkers was generally beneficial for binding protein and preventing enzyme leak during reusing cycles. Glyoxal performed the highest immobilization rate, though it hadn't been employed as a cross-linker for enzyme immobilization. DFF mediated cross-linking revealed the highest activity recovery, substrate conversion and residual activity after reusing cycles, suggesting better biocompatibility than glyoxal and GA. After 8 rounds of recycling, the residual activity of enzyme immobilized by DFF was 61.4 %, ∼30 % higher than that of GA. This study proved a potential alternative cross-linker DFF for the immobilization of enzyme cascade with high activity recovery and reusability, which could promote the efficient production of high value-added products from biomass monosaccharides.

Improved lipase performance by covalent immobilization of Candida antarctica lipase B on amino acid modified microcrystalline cellulose as green renewable support

Development of immobilized lipase with excellent catalytic performance and low cost is the major challenge for large-scale industrial applications. In this study, green renewable microcrystalline cellulose (MCC) that was hydrophobically modified with D-alanine (Ala) or L-lysine (Lys) was used for immobilizing Candida antarctica lipase B (CALB). The improved catalytic properties were investigated by experimental and computational methods. CALB immobilized on MCC-Ala with higher hydrophobicity showed better catalytic activity than CALB@MCC-Lys because the increased flexibility of the lid region of CALB@MCC-Ala favored the formation of open conformation. Additionally, the low root mean square deviation and the high β-sheet and α-helix contents of CALB@MCC-Ala indicated that the structure became more stable, leading to a significantly enhanced stability (54.80% and 90.90% relative activity at 70 °C and pH 9.0, respectively) and good reusability (48.92% activity after 5 cycles). This study provides a promising avenue to develop immobilized lipase with high catalytic properties for industry applications.

Immobilized lipase for sustainable hydrolysis of acidified oil to produce fatty acid

Acidified oil is obtained from by-product of crops oil refining industry, which is considered as a low-cost material for fatty acid production. Hydrolysis of acidified oil by lipase catalysis for producing fatty acid is a sustainable and efficient bioprocess that is an alternative of continuous countercurrent hydrolysis. In this study, lipase from Candida rugosa (CRL) was immobilized on magnetic Fe₃O₄@SiO₂ via covalent binding strategy for highly efficient hydrolysis of acidified soybean oil. FTIR, XRD, SEM and VSM were used to characterize the immobilized lipase (Fe₃O₄@SiO₂-CRL). The enzyme properties of the Fe₃O₄@SiO₂-CRL were determined. Fe₃O₄@SiO₂-CRL was used to catalyze the hydrolysis of acidified soybean oil to produce fatty acids. Catalytic reaction conditions were studied, including amount of catalyst, reaction time, and water/oil ratio. The results of optimization indicated that the hydrolysis rate reached 98% under 10 wt.% (oil) of catalyst, 3:1 (v/v) of water/oil ratio, and 313 K after 12 h. After 5 cycles, the hydrolysis activity of Fe₃O₄@SiO₂-CRL remained 55%. Preparation of fatty acids from high-acid-value by-products through biosystem shows great industrial potential.