Accurel MP 1000 as a support for the immobilization of lipase from Burkholderia cepacia : Application to the kinetic resolution of myo -inositol derivatives

Development and Evaluation of a Low-Cost Triglyceride Quantification Enzymatic Biosensor Using an Arduino-Based Microfluidic System

Overweight and obesity promote diabetes and heart disease onset. Triglycerides are key biomarkers for cardiovascular disease, strokes, and other health issues. Scientists have devised methods and instruments for the detection of these molecules in liquid samples. In this study, an enzymatic biosensor was developed using an Arduino-based microfluidic platform, wherein a lipolytic enzyme was immobilized on an ethylene-vinyl acetate polymer through physical adsorption. This low-cost optical biosensor employed a spectrophotometric transducer and was assessed in liquid samples to indirectly detect triglycerides and fatty acids using p-nitrophenol as an indicator. The average triglyceride level detected in the conducted experiments was 47.727 mg/dL. The biosensor exhibited a percentage of recovery of 81.12% and a variation coefficient of 0.791%. Furthermore, the biosensor demonstrated the ability to detect triglyceride levels without the need for sample dilution, ranging from 7.6741 mg/dL to 58.835 mg/dL. This study successfully developed an efficient and affordable enzymatic biosensor prototype for triglyceride and fatty acid detection. The lipolytic enzyme immobilization on the polymer substrate provided a stable and reproducible detection system, rendering this biosensor an exciting option for the detection of these molecules.

Carbohydrate microcapsules tailored and grafted for covalent immobilization of glucose isomerase for pharmaceutical and food industries

Carrageenan is one of the most common carbohydrates utilised in the entrapment industry to immobilise cells and enzymes. However, it lacks functionality. Carrageenan has been grafted to produce fructose by covalently immobilising glucose isomerase (GI). Fructose is one of the most widely used sweeteners in beverages, food production, and the pharmaceutical business. Up to 91.1 U g^-1 gel beads are immobilised by the grafted beads. Immobilized GI has a V_max of 13.8 times that of the free enzyme. pH of immobilized GI was improved from 6.5-7 to 6-7.5 that means more stability in wide pH range. Also, optimum temperature was improved and become 65-75 °C while it was at 70 °C for free enzyme. The immovability and tolerance of the gel beads immobilised with GI over 15 consecutive cycles were demonstrated in a reusability test, with 88 percent of the enzyme's original activity retained, compared to 60 percent by other authors. These findings are encouraging for high-fructose corn syrup producers.

The Application of Two-Phase Catalytic System in Enantioselective Separation of Racemic (R,S)-1-Phenylethanol

Kinetic resolution is one of the methods which allows obtaining enantiomerically pure compounds. In the study presented herein, enantioselective biotransformations of (R,S)-1-phenylethanol were performed with the use of various catalytic systems containing ionic liquids and n-heptane or toluene as a reaction medium, vinyl acetate or isopropenyl acetate as an acetylating agent, and lipases from Burkholderia cepacia or Candida rugosa. The conducted studies proved that the use of Burkholderia cepacia lipase, vinyl acetate, and n-heptane with [EMIM][BF4] allows obtaining enantiomerically pure 1-phenylethyl acetate, with the enantiomeric excess of products eep = 98.9%, conversion c = 40.1%, and high value of enantioselectivity E > 200. Additionally, the use of ionic liquids allowed us to reuse enzyme in 5 reaction cycles, ensuring the high operational stability of the protein.

An overview on the conversion of glycerol to value-added industrial products via chemical and biochemical routes

Glycerol is a common by-product of industrial biodiesel syntheses. Due to its properties, availability, and versatility, residual glycerol can be used as a raw material in the production of high value-added industrial inputs and outputs. In particular, products like hydrogen, propylene glycol, acrolein, epichlorohydrin, dioxalane and dioxane, glycerol carbonate, n-butanol, citric acid, ethanol, butanol, propionic acid, (mono-, di-, and triacylglycerols), cynamoil esters, glycerol acetate, benzoic acid, and other applications. In this context, the present study presents a critical evaluation of the innovative technologies based on the use of residual glycerol in different industries, including the pharmaceutical, textile, food, cosmetic, and energy sectors. Chemical and biochemical catalysts in the transformation of residual glycerol are explored, along with the factors to be considered regarding the choice of catalyst route used in the conversion process, aiming at improving the production of these industrial products.

Enzymes in the time of COVID-19: An overview about the effects in the human body, enzyme market, and perspectives for new drugs

The rising pandemic caused by a coronavirus, resulted in a scientific quest to discover some effective treatments against its etiologic agent, the severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2). This research represented a significant scientific landmark and resulted in many medical advances. However, efforts to understand the viral mechanism of action and how the human body machinery is subverted during the infection are still ongoing. Herein, we contributed to this field with this compilation of the roles of both viral and human enzymes in the context of SARS‐CoV‐2 infection. In this sense, this overview reports that proteases are vital for the infection to take place: from SARS‐CoV‐2 perspective, the main protease (M^pro) and papain‐like protease (PL^pro) are highlighted; from the human body, angiotensin‐converting enzyme‐2, transmembrane serine protease‐2, and cathepsins (CatB/L) are pointed out. In addition, the influence of the virus on other enzymes is reported as the JAK/STAT pathway and the levels of lipase, enzymes from the cholesterol metabolism pathway, amylase, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and glyceraldehyde 3‐phosphate dehydrogenase are also be disturbed in SARS‐CoV‐2 infection. Finally, this paper discusses the importance of detailed enzymatic studies for future treatments against SARS‐CoV‐2, and how some issues related to the syndrome treatment can create opportunities in the biotechnological market of enzymes and the development of new drugs.

Application of a constrained mixture design for lipase production by Penicillium roqueforti ATCC 10110 under solid-state fermentation and using agro-industrial wastes as substrate

Solid state fermentation (SSF) simulates the natural conditions fungal growth, where the amount of water in the reaction medium must be restricted, thus limiting the use of liquid substrate. An analytical strategy to deal with this limitation is the design of blending with constraints. Thus, the objective of the work was to optimize two constrained waste mixtures for the production of lipase by Penicillium roqueforti ATCC 10110 under SSF, using different substrates that combine solid and liquid waste. For this, the best fermentation time was determined through a fermentative profile, afterwards a restricted-mix design with lower and upper limits of the components of mixture I (cocoa residue, solid palm oil residue and liquid palm oil residue) and II (cocoa residue, mango residue and palm oil residue liquid palm) was applied. By means of Pareto and contour graphs, the maximum production points of lipase in mixtures I (6.67 ± 0.34 U g^-1) and II (6.87 ± 0.35 U g^-1) were obtained. The restricted mixture design proved to be a promising tool in the production of lipase by P. roqueforti ATCC 10110 under SSF since the use of restrictions is useful when intending to combine solid and liquid residues in fermentation processes.

Candida rugosa lipase immobilized on hydrophobic support Accurel MP 1000 in the synthesis of emollient esters

OBJECTIVES

To immobilize Candida rugosa lipase in Accurel MP 1000 (CRL-AMP) by physical adsorption in organic medium and apply in the synthesis of wax esters dodecanoyl octadecanoate 1 and hexadecanoyl octadecanoate 2 in a heptane medium, as well as evaluating the stability and recyclability of CRL-AMP in six reaction cycles.

RESULTS

The specific activity (A_sp) for CRL-AMP was 200 ± 20 U mg^-1. Its catalytic activity was 1300 ± 100 U g^-1. CRL-AMP was used in the synthesis of esters in heptane medium with a 1:1 acid:alcohol molar ratio at 45 °C and 200 rpm. In synthesis 1, conversion was 62.5 ± 3.9% in 30 min at 10% m v^-1 and 56.9 ± 2.8% in 54 min at 5% m v^-1; while in synthesis 2, conversion was 79.0 ± 3.9% in 24 min at 10% m v^-1, and 46.0 ± 2.4% in 54 min at 5% m v^-1. Reuse tests after six consecutive cycles of reaction showed that the biocatalyst retained approximately 50% of its original activity for both reaction systems.

CONCLUSIONS

CRL-AMP showed a high potential in the production of wax esters, since it started from low enzymatic load and high specific activities and conversions were obtained, in addition to allowing an increase in stability and recyclability of the prepared biocatalyst.

Revisiting Jatropha curcas Monomeric Esterase: A Dienelactone Hydrolase Compatible with the Electrostatic Catapult Model

Jatropha curcas contains seeds with a high oil content, suitable for biodiesel production. After oil extraction, the remaining mass can be a rich source of enzymes. However, data from the literature describing physicochemical characteristics for a monomeric esterase from the J. curcas seed did not fit the electrostatic catapult model for esterases/lipases. We decided to reevaluate this J. curcas esterase and extend its characterization to check this apparent discrepancy and gain insights into the enzyme's potential as a biocatalyst. After anion exchange chromatography and two-dimensional gel electrophoresis, we identified the enzyme as belonging to the dienelactone hydrolase family, characterized by a cysteine as the nucleophile in the catalytic triad. The enzyme displayed a basic optimum hydrolysis pH of 9.0 and an acidic pI range, in contrast to literature data, making it well in line with the electrostatic catapult model. Furthermore, the enzyme showed low hydrolysis activity in an organic solvent-containing medium (isopropanol, acetonitrile, and ethanol), which reverted when recovering in an aqueous reaction mixture. This enzyme can be a valuable tool for hydrolysis reactions of short-chain esters, useful for pharmaceutical intermediates synthesis, due to both its high hydrolytic rate in basic pH and its stability in an organic solvent.

Novel biotechnological formulations of cysteine proteases, immobilized on chitosan. Structure, stability and activity

Bromelain, papain, and ficin are studied the most for meat tenderization, but have limited application due to their short lifetime. The aim of this work is to identify the adsorption mechanisms of these cysteine proteases on chitosan to improve the enzymes' stability. It is known that immobilization can lead to a significant loss of enzyme activity, which we observed during the sorption of bromelain (protease activity compared to soluble enzyme is 49% for medium and 64% for high molecular weight chitosan), papain (34 and 28% respectively) and ficin (69 and 70% respectively). Immobilization on the chitosan matrix leads to a partial destruction of protein helical structure (from 5 to 19%). Using computer modelling, we have shown that the sorption of cysteine proteases on chitosan is carried out by molecule regions located on the border of domains L and R, including active cites of the enzymes, which explains the decrease in their catalytic activity upon immobilization. The immobilization on chitosan does not shift the optimal range of pH (7.5) and temperature values (60 °C for bromelain and papain, 37-60 °C for ficin), but significantly increases the stability of biocatalysts (from 5.8 times for bromelain to 7.6 times for papain).

Enhanced Performance of Immobilized Rhizopus oryzae Lipase on Coated Porous Polypropylene Support with Additives

The immobilization of Rhizopus oryzae lipase (RoL) by hydrophobic adsorption on polypropylene supports with additives was investigated. Additives such as hen egg albumin, sodium caseinate and CAVAMAX® W6 were used to coat the support during immobilization where the immobilized RoL on coated support was compared to those of noncoated support. Following the immobilization, the catalytic activity of immobilized RoL was characterized based on different temperatures and pH. The immobilized RoL without additives showed optimal lipase activity at an optimum temperature of 50 °C and pH 6. However, RoL lipase that was immobilized on support treated with CAVAMAX® W6 had better performance in terms of hydrolytic activity and stability as compared to other additives. In addition, by having a support treated with hen egg albumin, the immobilized RoL was capable of yielding higher ester during esterification reactions.

Efficient secretion expression of phospholipase D in Bacillus subtilis and its application in synthesis of phosphatidylserine by enzyme immobilization

Transphosphatidylation catalyzed by phospholipase D has gained increasing attention for producing phosphatidylserine (PS), which can be used in functional food and medicine. In this study, we investigated the effects of six signal peptides on the secretion of PLD (PLD_sa) from Streptomyces antibioticus TCCC 21059 in the food-grade GRAS bacterium Bacillus subtilis. It indicated that the optimal signal peptide DacB with an Ala-X-Ala sequence motif at the C-terminus showed the highest secretory expression ability, resulting in increased production of 2.84 U/mL PLD_sa. Then PLD_sa was immobilized on the epoxy-based carriers, and one of these carriers allowed PLD_sa loading of up to 2.7 mg/g. The immobilized PLD_sa was more stable over a wide range of pH value (4.5-7.5) and temperature (16 °C-60 °C) than free PLD_sa. Subsequently, the synthesis of PS from soybean phosphatidylcholine (PC) was carried out in purely aqueous solution using immobilized PLD_sa, leading to a high yield of 65%. The immobilized PLD_sa catalyst maintained a relative PS production of 60% after 5 recycles. Notably, the use of toxic solvent was completely eliminated in the whole process, which would be more profitable for the application of PS.

One pot clarification and debittering of grapefruit juice using co-immobilized enzymes@chitosanMNPs

In the present work, enzymes pectinase and naringinase were simultaneously co-immobilized on an eco-friendly chitosan coated magnetic nanoparticles (chitosanMNPs) by cross-linking using chitosan as a macro-molecular cross-linker. The maximum activity recovery of both enzymes in the co-immobilized form was obtained at chitosanMNPs to enzymes ratio of 1:3, 3% cross-linker concentration and 150 min cross-linking time. The synthesized MNPs before and after co-immobilization were characterized using different techniques. The prepared biocatalyst was found spherical with an average size below 200 nm and showed supermagnetic property with saturation magnetization of 38.28 emu/g. The optimum pH and temperature of both enzymes in co-immobilized form was found at 5.5 and 65 °C. The prepared biocatalyst exhibited an improved thermal stability with 1.8-fold increase in the half-life. The secondary structural analysis revealed that, prepared co-immobilized biocatalyst undergone changes in the conformational and structural rigidity due to macro-molecular cross-linker. The co-immobilized biocatalysts were evaluated for one pot clarification and debittering of grapefruit juice and found ~52% reduction in turbidity and ~85% reduction in the naringin content. The co-immobilized enzymes were recycled up to 7^th cycle and can be easily stored at room temperature for 30 days retaining up to 64% and 86% residual activities respectively.

Immobilisation of Candida rugosa lipase on a highly hydrophobic support: A stable immobilised lipase suitable for non-aqueous synthesis

Lipase from Candida rugosa (CrL) was immobilised on highly hydrophobic, octadecyl methacrylate resin (Lifetech™ ECR8806M) via interfacial adsorption. The aim was to produce a stable biocatalyst suitable for use in a range of lipid-modifying reactions. Immobilisation was carried out in 10 mM phosphate buffer (pH 6.0) over 24 h at 21 °C. High protein binding of 58.7 ± 4.9 mg/g dry support accounted for ∼53 % of the applied protein. The activity recovery against tributyrin was 74.0 ± 1.1 %. The specific activity of immobilised CrL against tributyrin was considerably higher than that of Novozym® 435, at 1.79 ± 0.05 and 1.08 ± 0.04 U/mg bound protein, respectively. Incubation with high concentrations (10 % w/v) of both Triton X-100 and SDS resulted in only a small reduction in immobilised lipase activity. Solvent-free synthesis of glycerides by the FFA-saturated immobilised CrL was successful over 6 reaction cycles, with no apparent loss of activity.

Advances in Recombinant Lipases: Production, Engineering, Immobilization and Application in the Pharmaceutical Industry

Lipases are one of the most used enzymes in the pharmaceutical industry due to their efficiency in organic syntheses, mainly in the production of enantiopure drugs. From an industrial viewpoint, the selection of an efficient expression system and host for recombinant lipase production is highly important. The most used hosts are Escherichia coli and Komagataella phaffii (previously known as Pichia pastoris) and less often reported Bacillus and Aspergillus strains. The use of efficient expression systems to overproduce homologous or heterologous lipases often require the use of strong promoters and the co-expression of chaperones. Protein engineering techniques, including rational design and directed evolution, are the most reported strategies for improving lipase characteristics. Additionally, lipases can be immobilized in different supports that enable improved properties and enzyme reuse. Here, we review approaches for strain and protein engineering, immobilization and the application of lipases in the pharmaceutical industry.

Effect of shaking speed on immobilization of cephalosporin C acylase: Correlation between protein distribution and properties of the immobilized enzymes

During enzyme immobilization, enzyme activity and protein distribution are affected by various factors such as enzyme load, temperature, and pH. In general, two types of protein distribution patterns (heterogeneous or homogeneous) are observed inside a porous carrier, owing to differences in preparation parameters. During the immobilization of a fusion protein (CCApH) of cephalosporin C acylase (CCA) and pHluorin (a pH-sensitive mutant of green fluorescent protein), different shaking speeds induced obvious differences in protein distribution on an epoxy carrier, LX-1000EPC. Enzyme immobilization with a homogeneous distribution pattern was observed at a low shaking speed (120 rpm) with an operational stability of 10 batches at 37°C. The operational stability of an immobilisate with heterogeneous protein distribution prepared at a high shaking speed (200 rpm) was six batches. Given the pH-sensitive characteristics of pHluorin in the fusion protein, the intraparticle pH of CCApH immobilisates during catalysis was monitored using confocal laser scanning microscopy. The microenvironmental pH of the immobilisate with heterogeneous protein distribution sharply decreased by about 2 units; this decrease in the pH may be detrimental to the life-span of immobilized CCA. Thus, this work demonstrates the good operational stability of pH-sensitive proton-forming immobilized enzymes with homogeneous protein distribution.

The Immobilization of Lipases on Porous Support by Adsorption and Hydrophobic Interaction Method

Four major enzymes commonly used in the market are lipases, proteases, amylases, and cellulases. For instance, in both academic and industrial levels, microbial lipases have been well studied for industrial and biotechnological applications compared to others. Immobilization is done to minimize the cost. The improvement of enzyme properties enables the reusability of enzymes and facilitates enzymes used in a continuous process. Immobilized enzymes are enzymes physically confined in a particularly defined region with retention to their catalytic activities. Immobilized enzymes can be used repeatedly compared to free enzymes, which are unable to catalyze reactions continuously in the system. Immobilization also provides a higher pH value and thermal stability for enzymes toward synthesis. The main parameter influencing the immobilization is the support used to immobilize the enzyme. The support should have a large surface area, high rigidity, suitable shape and particle size, reusability, and resistance to microbial attachment, which will enhance the stability of the enzyme. The diffusion of the substrate in the carrier is more favorable on hydrophobic supports instead of hydrophilic supports. The methods used for enzyme immobilization also play a crucial role in immobilization performance. The combination of immobilization methods will increase the binding force between enzymes and the support, thus reducing the leakage of the enzymes from the support. The adsorption of lipase on a hydrophobic support causes the interfacial activation of lipase during immobilization. The adsorption method also causes less or no change in enzyme conformation, especially on the active site of the enzyme. Thus, this method is the most used in the immobilization process for industrial applications.

Immobilization of laccase on Sepharose-linked antibody support for decolourization of phenol red

Laccases which are considered as "green tools" in biotechnology have potential to degrade toxic contaminants/synthetic dyes present in industrial effluents. The loss in activity and stability of laccases are key challenges faced in their potential industrial applications. Here, laccase from Trametes versicolor (polypore mushroom) was immobilized on Sepharose-linked antibody support to carry out the decolourization of phenol red. This support was prepared by covalent linking of anti-laccase antibodies to CNBr activated Sepharose at pH 8.5, and then laccase was immobilized on this affinity support at pH 5.0. The amount of laccase immobilized was approximately 33 mg per gram of the affinity support, giving an immobilization yield of 83.4%. The immobilized enzyme displayed an activity of 3.88 U with an effectiveness factor (η) of 0.90. Immobilization of laccase led to significant enhancement in thermal and storage stability. The immobilized enzyme retained 44% of its activity after 10 cycles of continuous use. The decolourization of phenol red dye obtained by immobilized and soluble laccase after 6 h of incubation at 50 °C was 80 and 56%, respectively. Thus, immobilization of laccase on Sepharose-linked antibody support leads to remarkable improvement in its various properties, making it more versatile for industrial applications.

Amano Lipase PS from Burkholderia cepacia- Evaluation of the Effect of Substrates and Reaction Media on the Catalytic Activity

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Lipases in the native or immobilized form have commonly been used as catalysts in the chemical and pharmaceutical industry. One of the widely available enzyme catalysts on the market is lipase from Burkholderia cepacia (BCLs), previously called Pseudomonas cepacia (PCLs). This enzyme is applied, among others, in the stereoselective acylation of molecules to achieve chiral pure enantiomers of drugs or their building blocks. In this study, Amano lipase PS (APS-BCL), which is a commercial lipase from Burkholderia cepacia (BC) was tested. The lipolytic activity of APS-BCL by hydrolysis of vegetable oils and enantioselective activity of APS-BCL by the kinetic resolution of (R,S)-1-phenylethanol with using isopropenyl acetate as an acyl donor were evaluated. An effect of reaction media with different logP values (t-butyl methyl ether, dichloromethane, diisopropyl ether, toluene, cyclohexane, n-hexane, isooctane and n-heptane) on the enantioselective activity of lipase was also studied. The high value of the enantiomeric ratio (E =308.5) with the utilization of isopropenyl acetate was achieved. Whereas, the best reaction medium turned out to be diisopropyl ether, C =47.9%, eep =98%, ees =90%, after 24 h of incubation. Moreover, the influence of ω6/ω9 polyunsaturated fatty acids (PUFAs) ratio in commercial (peanut, camelina, rape, pumpkin seed, walnut, sesame, avocado, rice, corn, black cumin, hemp, safflower, grape seed) oils was investigated for the lipase activity. For the first time, the cut-off limit of ω6/ω9 ratio was proposed. The ratio equal to or higher than 2.3 allows achieving higher lipolytic activity.

Principles of lipid-enzyme interactions in the limbus region of the catalytic site of Candida antarctica Lipase B

Lipases (E.C. 3.1.1.3) are ubiquitous hydrolases for the carboxyl ester bond of water-insoluble substrates such as triacylglycerols and phospholipids. Candida antarctica Lipase B (CALB) acts in aqueous as well as in low-water media, thus being of considerable biochemical significance with high interest also for its industrial applications. The hydrolysis reaction follows a two-step mechanism, or 'interfacial activation', with adsorption of the enzyme to a heterogeneous interface and subsequent enhancement of the lipolytic activity. Once positioned within the catalytic triad, substrates are then hydrolysed, and products released. However, the intermediate steps of substrate transfer from the lipidic-aqueous phase to the enzyme surface and then down to the catalytic site are still unclear. By inhibiting CALB with ethyl phosphonate and incubating with glyceryl tributyrate (2,3-di(butanoyloxy)propyl butanoate), the crystal structure of the lipid-enzyme complex, at 1.55 Å resolution, shows the tributyrin in the limbus region of active site. The substrate is found 10 Å above the catalytic Ser, with the glycerol backbone pre-aligned for further processing by key interactions via an extended water network with α-helix10 and α-helix5. The findings offer new elements to elucidate the mechanism of substrate recognition, transfer and catalysis of Candida antarctica Lipase B (CALB) and lipases in general.

Hydrophilic Glyceryl Ferulates Preparation Catalyzed by Free Lipase B from Candida antartica

Ferulic acid (FA), 4-hydroxyl-3-methoxy-2-benzylacrylic acid, has antioxidant, anticancer and ultraviolet absorption activities. However, the low hydrophilicity of FA has limited its application. Glyceryl ferulate (FG), which is an all-natural hydrophilic derivative of FA, can be used as an antioxidant and UV filter in food and cosmetic formulations. However, the applications of FG in these fields are limited due to its low content in nature. In this work, free liquid lipase was firstly used as a catalyst for FG preparation. Several different free liquid lipases (Candida antartica lipase-B, Candida antartica lipase-A, Thermomyces lanuginosus (Lipozyme TL 100L)) were screened and compared. The effects of the transesterification parameters (time, temperature, enzyme load and substrate ratio) were optimized and evaluated by response surface methodology. A reaction thermodynamic investigation was also performed. The results showed that, among the tested free lipases, the maximum FG yield (84.8±1.5%) was achieved using free Candida antartica lipase-B. Under the optimized conditions (an atmospheric system, an enzyme load of 11.1% and a 20:1 molar ratio of glycerol to EF at 70°C for 39.5 h), the FG yield and EF conversion were 84.8±1.5% and 95.7±1.2%, respectively. The activation energies of FG formation and EF conversion were 56.4 and 58.0kJ/mol, respectively.

Enzyme immobilized in BioMOFs: Facile synthesis and improved catalytic performance

Biological metal-organic frameworks (BioMOFs), an emerging sub-class of MOFs, are prepared from metals and biological ligands (bioligands). Benefit from the low toxicity and good biocompatibility of bioligands, BioMOFs can be used in biomedicine and biocatalysis. In this work, a novel approach was developed for fabricating BioMOFs materials (Co-Cys BioMOFs) from cobalt salt and cystine, meanwhile nitrile hydratase (NHase) was in-situ encapsulated during the synthesis process. The obtained NHase-BioMOFs biocomposits named NHase@Co-Cys was characterized by SEM, TEM, XPS, etc. The preparation parameters and stabilities of NHase@Co-Cys were investigated. The maximum encapsulation yield and specific activity of NHase@Co-Cys were 92.71% and 139.04 U/g_{immobilized NHase}, respectively. The thermal stability of NHase@Co-Cys was improved by approximately 5-fold at 55 °C. The activity of NHase after immobilization was retained nearly 60% after incubating at pH 4.0 and 10.0 for 7 h. The NHase@Co-Cys showed similar catalytic capacity compared with free NHase in producing nicotinamide. After 7 h of reaction catalyzed by free NHase (14.51 U) and NHase@Co-Cys (12.76 U), the yield of nicotinamide was 90.94% and 86.36%, respectively. The activity of NHase@Co-Cys remained 83.85% of the original activity after recycling for 10 times. These results suggested that the NHase@Co-Cys is an effective approach to enhance the enzymatic properties and demonstrated a broad application prospect in industrial production.

Statistical optimization of cultural medium composition of thermoalkalophilic lipase produced by a chemically induced mutant strain of Bacillus atrophaeus FSHM2

Extremophilic microbial derived lipases have been widely applied in different biotechnological processes due to their resistance to harsh conditions such as high salt concentration, elevated temperature, and extreme acidic or alkaline pH. The present study was designed to overproduce the halophilic, thermoalkalophilic lipase of Bacillus atrophaeus FSHM2 through chemically induced random mutagenesis and optimization of cultural medium components assisted by statistical experimental design. At first, improvement of lipase production ability of B. atrophaeus FSHM2 was performed through exposure of the wild bacterial strain to ethidium bromide for 5-90 min to obtain a suitable mutant of lipase producer (designated as EB-5, 4301.1 U/l). Afterwards, Plackett-Burman experimental design augmented to D-optimal design was employed to optimize medium components (olive oil, maltose, glucose, sucrose, tryptone, urea, (NH₄)₂SO₄, NaCl, CaCl₂, and ZnSO₄) for lipase production by the EB-5 mutant. A maximum lipase production of 14,824.3 U/l was predicted in the optimum medium containing 5% of olive oil, 0.5% of glucose, 0.5% of sucrose, 2% of maltose, 2.5 g/l of yeast extract, 1.75 g/l of urea, 1.75 g/l of (NH₄)₂SO₄, 2.5 g/l of tryptone, 2 g/l of NaCl, 1 g/l of CaCl₂, and 1 g/l of ZnSO₄. A mean value of 14,773 ± 576.9 U/l of lipase was acquired from real experiments.

Improvement of lipase activity by synergistic immobilization on polyurethane and its application for large-scale synthesizing vitamin A palmitate

We have developed an improved and effective method to immobilize lipase on hydrophobic polyurethane foam (PUF) with different modifications. PUF was treated with hydrochloric acid to increase the active sites and then the active carboxyl groups and amino groups were exposed. Enzyme activity of lipase immobilized on PUF-HCL (8000 U/g) was 50% higher than that of lipase immobilized on PUF (5300 U/g). There is an increase in the activity of the immobilized lipase on AA/PEI-modified support (115,000 U/g), a 2.17-fold increase compared to lipase immobilized on the native support was observed. The activity of immobilized lipases was dependent on the PEI molecular weight, with best results from enzyme immobilized on PUF-HCL-AA/PEI (MW 70,000 Da, 12,800 U/g)), which was 2.41 times higher compared to that of the same enzyme immobilized on PUF. These results suggest that the activity of immobilized lipase is influenced by the support surface properties, and a moderate support surface micro-environment is crucial for improving enzyme activity. Finally, the immobilized lipase was used for the production of vitamin A palmitate. The immobilized lipase can be reused for up to 18 times with a conversion rate above 90% for 12 h in a 3 L bioreactor. Research highlights An efficient immobilization protocol on polyurethane foam was developed Polyethyleneimine and acetic acid were used to regulate the micro-environment concurrently The activity of lipase immobilized on PUF-HCL-AA/PEI was improved by 2.41 times Immobilized lipase exhibited excellent operational stability for vitamin A palmitate synthesis.

Reactor Selection for Effective Continuous Biocatalytic Production of Pharmaceuticals

Enzyme catalyzed reactions are rapidly becoming an invaluable tool for the synthesis of many active pharmaceutical ingredients. These reactions are commonly performed in batch, but continuous biocatalysis is gaining interest in industry because it would allow seamless integration of chemical and enzymatic reaction steps. However, because this is an emerging field, little attention has been paid towards the suitability of different reactor types for continuous biocatalytic reactions. Two types of continuous flow reactor are possible: continuous stirred tank and continuous plug-flow. These reactor types differ in a number of ways, but in this contribution, we focus on residence time distribution and how enzyme kinetics are affected by the unique mass balance of each reactor. For the first time, we present a tool to facilitate reactor selection for continuous biocatalytic production of pharmaceuticals. From this analysis, it was found that plug-flow reactors should generally be the system of choice. However, there are particular cases where they may need to be coupled with a continuous stirred tank reactor or replaced entirely by a series of continuous stirred tank reactors, which can approximate plug-flow behavior. This systematic approach should accelerate the implementation of biocatalysis for continuous pharmaceutical production.

Novozym 435: the “perfect” lipase immobilized biocatalyst?

Novozym 435 (N435) is a commercially available immobilized lipase produced by Novozymes with its advantages and drawbacks.

Efficient Physisorption of Candida Antarctica Lipase B on Polypropylene Beads and Application for Polyester Synthesis

In the present work, Candida antarctica lipase B (CaLB) was adsorbed onto polypropylene beads using different reaction conditions, in order to investigate their influence on the immobilization process and the enzyme activity of the preparations in polymerization reactions. In general, lower salt concentrations were more favorable for the binding of enzyme to the carrier. Polymerisation of dimethyl adipate (DMA) and 1,4-butanediol (BDO) was investigated in thin-film systems at 70 °C and at both atmosphere pressure (1000 mbar) and 70 mbar. Conversion rates and molecular masses of the reaction products were compared with reactions catalyzed by CaLB in its commercially available form, known as Novozym 435 (CaLB immobilized on macroporous acrylic resin). The best results according to molecular weight and monomer conversion after 24 h reaction time were obtained with CaLB immobilized in 0.1 M Na2HPO4\NaH2PO4 buffer at pH 8, producing polyesters with 4 kDa at conversion rates of 96% under low pressure conditions. The stability of this preparation was studied in a simulated continuous polymerization process at 70 °C, 70 mbar for 4 h reaction time. The data of this continuous polymerizations show that the preparation produces lower molecular weights at lower conversion rates, but is comparable to the commercial enzyme concerning stability for 10 cycles. However, after 24 h reaction time, using our optimum preparation, higher molecular weight polyesters (4 kDa versus 3.1 kDa) were obtained when compared to Novozym 435.

An Organic Solvent-Tolerant Lipase with Both Hydrolytic and Synthetic Activities from the Oleaginous Fungus Mortierella echinosphaera

Lipase enzymes of the oleaginous fungal group Mortierella are rarely studied. However, considering that most commercial lipases are derived from filamentous fungal sources, their investigation can contribute to the cost-effective development of new biotechnological processes. Here, an extracellular lipase with a molecular mass of 30 kDa was isolated from Mortierella echinosphaera CBS 575.75 and characterized. The purified lipase exhibited an optimal p-nitrophenyl palmitate (pNPP)-hydrolyzing activity at 25 °C and pH 6.6-7.0 and proved to be highly stable at temperatures up to 40 °C and under broad pH conditions. The enzyme was active under low temperatures, retaining 32.5% of its activity at 10 °C, and was significantly stable in polar and non-polar organic solvents. The Km, Vmax, and kcat for pNPP were 0.336 mM, 30.4 μM/min, and 45.7 1/min for pNPP and 0.333 mM, 36.9 μM/min, and 55.6 1/min for pNP-decanoate, respectively. The pNPP hydrolysis was inhibited by Hg2+, N-bromosuccinimide, and sodium dodecyl sulfate, while ethylenediaminetetraacetic acid and metal ions, such as Ca2+, Mg2+, Na⁺, and K⁺ enhanced the activity. The purified lipase had non-regioselective activity and wide substrate specificity, showing a clear preference for medium-chained p-nitrophenyl esters. Besides its good transesterification activity, the enzyme appeared as a suitable biocatalyst to operate selective esterification reactions to long-chained alkyl esters. Adsorption to Accurel MP1000 improved the storage stability of the enzyme at 5 °C. The immobilized lipase displayed tolerance to a non-aqueous environment and was reusable for up to five cycles without significant loss in its synthetic and hydrolytic activities. These findings confirm the applicability of both the free and the immobilized enzyme preparations in future research.

Quick separation and enzymatic performance improvement of lipase by ionic liquid-modified Fe3O4 carrier immobilization

To promote the activity and stability of immobilized porcine pancreatic lipase (PPL), novel carrier was combined with special immobilization method. Enzymatic activity was enhanced after immobilized onto ionic liquid modified magnetic Fe₃O₄ by electrostatic adsorption. Activity of immobilized enzyme (PPL-IM/BF₄-Fe₃O₄@CA) reached 596 U/g PPL. Through the combination of electrostatic adsorption and embedding immobilization methods, we improve binding force between the carrier and enzyme, and further enhance the efficiency and stability of immobilized enzyme. The activity of PPL-IM/BF₄-Fe₃O₄@CA after repeated third use was 78%. After storage at room temperature for 5 days, the residual activity was 89%. Enzymatic properties and catalytic kinetics of immobilized enzymes were studied, and the effect mechanism of ionic liquid modified Fe₃O₄ on PPL was revealed. The effect of ionic liquid on the carrier structure was investigated by characterization of XRD, FT-IR, SEM and TG. The mechanism and enzymatic properties of immobilized PPL via electrostatic adsorption and embedding were analyzed. A novel and efficient immobilized PPL was developed.