Search

Substrate accessibility by an enzyme is the rate-limiting step in cellulose digestion. The newly schematized humic acid (HA)-assisted alkali pretreatment was done to delignify and upgrade the bagasse's characteristics for the pragmatic accessibility of the enzyme. The proposed pretreatment resulted in ~90–100% lignin recovery with distinctive properties. After delignification, the upgraded biomass harnessed as solid support to immobilize the enzyme, ultimately reducing the cost and step for designing physical support for immobilization. HA, an active ligand, with its enriched functional moieties such as carboxyl, carbonyl, hydroxyl, and amide group, bind prior to the substrate (i.e., delignified bagasse) that immobilizes enzyme and hydrolyses cellulose portion. The interaction mechanisms of pretreated bagasse with enzyme were demonstrated through molecular docking using Auto Dock software and UV (Ultraviolet) Spectrophotometric analysis. The pretreatment efficiency was analyzed as a case study in a large-scale reactor by subjecting pretreated bagasse to batch enzymatic hydrolysis with a low enzyme-loading rate of 14 FPU/g of cellulose. Cellulose conversion of 88% (i.e., 20.92 g/L of glucose) was achieved in 48 h, respectively. Subsequently, the flat-sheet cross-flow ultrafiltration (UF) membrane-based continuous recycling unit was operated at a flux of 22.5 L/m2hr toward the purification of glucose (i.e., 15.75 g/L of glucose). The performance of PES10-UF membrane module chaperoning with hydrolysis reactor for the designed hydrolysis scheme was examined in light of critical flux, pure water permeability, and irreversible fouling studies. The flow rate of 300 LPH (L/hr) and the transmembrane membrane pressure (TMP) of 1.5 bar showed high antifouling performance. [ABSTRACT FROM AUTHOR]

Existing antifouling coatings for marine environments rely on the toxicity of copper and small-molecule additives to prevent organism growth. These come with a myriad of environmental and health-related risks, as these additives inevitably leach into seawater. Enzyme-based antifouling polymers have tremendous potential as part of an environmentally innocuous antifouling strategy, but have not yet been commercially realized. Biofouling begins with small molecules and polymers that initiate settlement for larger organisms. Using an enzymatic coating to rapidly hydrolyze these compounds could reduce the surface concentration of these attractive polymers and prevent organism growth. Here, antifouling xylanase and lysing complex enzymes were covalently tethered to surfaces using isoindolinone groups and click chemistry. We found that xylanase and lysing complex continue to hydrolyze xylosidic bonds in hemicellulose polysaccharides after covalent tethering, and the coating maintained activities of > 80% and > 50%, respectively, after 2 months while submerged in artificial seawater, demonstrating this material's potential as an eco-friendly antifouling coating. [ABSTRACT FROM AUTHOR]

l‐Theanine (l‐Th) was synthesized by simply mixing the reactants (l‐glutamine and ethylamine in water) at 25 °C and Bacillus subtilis γ‐glutamyl transferase (BsGGT) covalently immobilized on glyoxyl‐agarose according to a methodology previously reported by our research group; neither buffers, nor other additives were needed. Ratio of l‐glutamine (donor) to ethylamine (acceptor), pH, enzymatic units (IU), and reaction time were optimized (molar ratio of donor/acceptor=1 : 8, pH 11.6, 1 IU mL−1, 6 h), furnishing l‐Th in 93 % isolated yield (485 mg, 32.3 g L−1) and high purity (99 %), after a simple filtration of the immobilized biocatalyst, distillation of the volatiles (unreacted ethylamine) and direct lyophilization. Immobilized BsGGT was re‐used (four reaction cycles) with 100 % activity retention. This enzymatic synthesis represents a straightforward, fast, high‐yielding, and easily scalable approach to l‐Th preparation, besides having a favorable green chemistry metrics. [ABSTRACT FROM AUTHOR]

The creation of a networked protocell system with collective behaviors is one of the key developmental directions in the step-by-step development process of the life-inspired materials. In this regard, the emergent characteristics ofproteinosomes aggregations were demonstrated, including accelerated settling velocity, population surviving et al. And inspired by the characteristic of resistance to the negative pressure phagocytosis of micropipette, the method of enhancing utilization rate of enzyme was developed based on the kind of "hand in hand" architecture of proteinosomes aggregations. [Display omitted] Compared with the individuals, the collective behavior of biotic communities could show certain superior characteristics. Inspired by this idea and based on the conjugation between phenylboronic acid-grafted mesoporous silica nanoparticles and the polysaccharide functionalized membrane of proteinosomes, a type of proteinosomes-based aggregations was constructed. We demonstrated the emergent characteristics of proteinosomes aggregations including accelerated settling velocity and population surviving by sacrificing outside members for the inside. Moreover, this kind of "hand in hand" architecture provided the proteinosomes aggregations with the characteristic of resistance to the negative pressure phagocytosis of micropipette, as well as enhancing utilization rate of the encapsulated enzymes. Overall, it is anticipated that the construction and application of proteinosomes aggregations could contribute to advance the functionality of life-like assembled biomaterial in another way. [ABSTRACT FROM AUTHOR]

For the development of efficient and green industrial processes, the combination of biocatalysis and flow chemistry holds great promises. Flow chemical utilization of biocatalysts, essentially made possible by the immobilization (or retention) of enzymes in flow reactors, has attracted increased academic attention during recent years. In the present review we present an overview of immobilization strategies suitable for flow chemistry, particularly focusing on recently developed carrier‐free immobilization methods, highlighting advances in the field and presenting future trends. [ABSTRACT FROM AUTHOR]

A method is developed for carrier‐free immobilization of multi‐enzyme complexes with more than four enzymes by utilization of polypeptide interactions (SpyCatcher‐SpyTag and dockerin‐cohesin) and enzyme component self‐oligomerization. Two pairs of scaffoldins with different arrangements of SpyCatcher‐SpyTag and cohesins are prepared to recruit the four dockerin‐containing cascade enzymes (i. e. alpha‐glucan phosphorylase, phosphoglucomutase, inositol 1‐phosphate synthase, and inositol 1‐phosphatase) that can convert starch into inositol, forming multi‐enzyme complexes. These self‐assembled enzyme complexes show higher initial reaction rates than the four‐enzyme cocktail. Moreover, water‐insoluble self‐assembled multi‐enzyme complexes are observed, being the carrier‐free immobilized multi‐enzyme complex aggregates. These immobilized enzyme complexes can be recycled easily by simple centrifuging followed by resuspension for another round of reaction. Not only can these immobilized enzyme complexes be obtained by mixing the purified enzyme components, but also by the mixing of crude cell extracts. Therefore, the strategy for the carrier‐free immobilization of enzyme complex sheds light on improving the catalytic capability of in vitro synthetic enzymatic biosystems. [ABSTRACT FROM AUTHOR]

In this study, a novel conductive polymer comprising biosensor based on poly‐2,2′‐(9,9‐dioctyl‐9 h‐fluorene‐2,7‐diyl)bistiophene (Poly(BT)) and acetylcholinesterase (AChE) was reported for the determination of paraoxon. This practical biosensor allowed to catalyze electrochemical oxidation of acetylthiocholine (+0.6 V vs. Ag reference). The detection range for acetylcholine chloride (AThCl) with Poly(BT)/AChE was found to be 0.025–4 mM. In pesticide analysis, wide linear ranges from 0.5 to 1 μg/L and 1 to 14 μg/L, and a low detection limit of 0.033 μg/L were estimated. Under optimum operating conditions, the developed biosensor was used for pesticide detection in milk and tap water samples, effectively. [ABSTRACT FROM AUTHOR]

The use of agricultural residue as a substrate and implementation of nanomaterials for cellulase immobilization can improve the efficiency at higher temperature and will lead to reduce the cost of cellulose-assisted biofuel production. The immobilization utilizing cellulase with amino, chitosan, or polymeric functionalities enhanced stability, activity, reusability, inhibition reduction, purification, and selectivity during enzymatic hydrolysis. Covalent interaction between the substrate and the cellulose marks in greater enzymatic immobilization, which pilots to higher biofuel production. Among the various techniques available for immobilization of cellulase on activated and functionalized magnetic nanoparticles, glutaraldehyde-based covalent binding are the most efficient process for cellulase immobilization. This review provides an overview of different cellulase immobilization strategies, factors, and its kinetics for enhanced biofuel production. The expanding need for low-cost immobilized cellulase, as well as its diverse applications in a variety of industries, is propelling research in this field. [ABSTRACT FROM AUTHOR]

Candida rugosa lipase was immobilized on graphene oxides magnetized with NiFe 2 O 4 nanoparticles (NiFe 2 O 4 -GO) and used for the transesterification of algal lipids. The VSM, FE-SEM, EDS, and FTIR analyses were done to investigate the features of nanoparticles, graphene oxide, and synthesized magnetic nanobiocatalyst. These tests confirmed the successful immobilization of Candida rugosa lipase on the base. Immobilization was caused via interfacial activation on hydrophobic supports. The lipase immobilization process was studied using different enzyme concentrations (30–160 µg/ml) at different incubation times (1–5 h). It was found that 100 µg/ml enzyme concentration (3.3 mg supports/ml solution) for 2 h incubation time were the best conditions which led to the immobilization efficiency of 78%. The results revealed that in comparison to the free enzyme, the immobilized enzyme is more thermal and pH resistant; it could retain 70% of its initial activity at 60 °C and lose only 20% at pH 9. Immobilized lipase retained 47% of its initial activity after 6 cycles of hydrolysis at 37 °C and pH 7, demonstrating its reusability and resistance. Biodiesel production efficiency was obtained 80% and 68% when using free and immobilized lipase as biocatalysts, respectively. [Display omitted] • Micro algae lipid was used to produce biodiesel using immobilized lipase. • Immobilized lipase on GO-NiFe 2 O 4 can retain its 70% activity at high pH. • Immobilized lipase can retain almost 50% of its activity after 6 cycles of use. • Biodiesel efficiency for immobilized lipase and free were 68% and 80% respectively. [ABSTRACT FROM AUTHOR]

Immobilization of enzymes is one of the protein engineering methods used to improve their thermal and long-term stabilities. Immobilized pectinase has become an essential biocatalyst for optimization in the food processing industry. Herein, nanostructured magnetic nanoparticles were prepared in situ for use as supports to immobilize pectinase. The structural, morphological, optical and magnetic features and the chemical compositions of the nanoparticles were characterized. Nanoparticle agglomeration and low porosity were observed due to the synthetic conditions. These nanoparticles exhibited superparamagnetic behavior, which is desirable for biotechnological applications. The maximum retention rate for the enzyme was observed at pH 4.5 with a value of 1179.3 U/mgNP (units per milligram of nanoparticle), which was equivalent to a 65.6% efficiency. The free and immobilized pectinase were affected by the pH and temperature. The long-term instability caused 40% and 32% decreases in the specific activities of the free and immobilized pectinase, respectively. The effects of immobilization were analyzed with kinetic and thermodynamic studies. These results indicated a significant affinity for the substrate, a decreased reaction rate, and improved thermal stability of the immobilized pectinase. The reusability of the immobilized pectinase was preserved effectively during cycling, with only a 21.2% decrease in activity observed from the first to the last use. Therefore, alternative magnetic nanoparticles are presented for immobilizing and maintaining the thermostability of pectinase.

Abstract The combination of enzymes and chemically responsive smart materials presents considerable opportunities in anti‐fouling, sensing or medicine. Among stimuli‐responsive polymers, liquid crystal elastomers (LCEs) have emerged as a leading actuator platform due to their inherent programmability, realizing large shape transformations upon exposure to stimuli. Herein, three different hydrolytic enzymes are immobilized into acid‐responsive LCEs, which impart the LCEs with sensitivity to three distinctive classes of biomolecules: lipids, carbohydrates, and peptides. Dye‐doped biocatalytic LCEs readily switch their color and shape upon exposure to the appropriate substrate. Twisted nematic patterning and direct ink writing are used to showcase the versatility of shape changes the enzyme‐containing LCEs may undergo. Multiplexed responsiveness is also demonstrated using a connected array of 3D printed disks, each containing a different enzyme, highlighting the excellent chemical selectivity of the LCEs. This work presents a novel platform of versatile bioresponsive color‐switchable actuators that may have application in a wide range of fields.

Biomimetic engineering presents an insightful strategy to access fascinating biocomposites integrating biological, chemical, and material functions. Herein, a new self‐propelled hydrogen‐bonded enzymatic framework through a biomimetic bottom‐up strategy is reported. The metal‐free, mesoporous, and photoactive hydrogen‐bonded organic framework (HOF) exoskeleton is in situ grown around catalase (CAT), an enzyme well known for its ability for the biocatalytic O2 generation. This HOF biomimetic method affords the ultrahigh encapsulation efficiency of CAT, yet well preserves the high crystallinity and periodically arranged mesochannels of HOF. The resultant hydrogen‐bonded enzymatic framework enables the self‐propelled motion with the help of a biocatalytic O2 bubble. Given the exquisite architecture, the HOF shell can serve as the dynamical sorbent for pollutant removal. More than that, it is showcased that the intrinsic photoactivity of HOF can be improved by the self‐propelled motion.

Abstract Compartmentalization is a ubiquitous feature of life, with a membrane interface that regulates molecular transport and exhibits bioactivities. An artificial enzyme‐integrated membrane cascade system can mimic such interactive properties across different length scales for in vitro application. Here, it is shown that a reticulated nanoporous framework membrane with nano‐caged enzymes presents the first modular macroscale platform for the compartmentalized biocatalytic system interfaced with an external medium. Catalase (CAT)‐integrated polyurea membrane scaffold is prepared by a simple pressurization procedure for a model cyclic cascade of glucose oxidase/catalase (GOx/CAT). The bicontinuous nanoporous membrane readily constructs a compartmentalized system interfacing the glucose/GOx solution and the external environment and mediates glucose oxidation by a cascade reaction under anaerobic or aerobic conditions. Furthermore, the membrane compartment exhibits multiple bioactive capabilities and barrier properties, including hydrogen peroxide detoxification, in situ oxygen generation, and protease exclusion. This work suggests a new strategy toward a robust modular biocatalytic membranous interface to mediate biochemical reaction cascades occurring in a compartment interfaced to an external environment, promising for potential applications in biohybrid devices embedded with tissues and cells.

In the present study, we aimed to develop a fast, non-toxic ultrasonic-assisted technique for the preparation of graphene oxide (GO) and GO that were accessorized with Fe3O4 (GO-Fe3O4) for enzyme immobilization. The structural properties of nanosheets were determined by FTIR, XRD, and SEM. Immobilized enzymes on the GO-Fe3O4 and GO were counted. Enzyme activity, reusability, and improvements in enzyme stability were studied. According to the results, the immobilization efficiency was 256.86 mg ficin/GO (g), and 253.63 mg ficin/GO-Fe3O4 (g). Furthermore, immobilized ficin was affected in terms of stability by variations in pH and temperature. The immobilized ficin on the GO-Fe3O4 could be easily recycled from the reaction medium by applying external magnetic separation, involving 10 cycles for 120 days. Over this period and with this number of cycles, the immobilized enzyme on the GO-Fe3O4 retained 74% of its original activity, whereas the immobilized enzyme on the GO was recycled from the reaction medium after centrifuging, thereby retaining 70% of its original activity. Thus, GO and GO-Fe3O4 nanosheets were obtained efficiently from the ultrasonic-assisted technique and can be regarded as excellent nanocarriers for enzyme immobilization.

In recent years, simulations have been used to great advantage to understand the structural and dynamic aspects of distinct enzyme immobilization strategies, as experimental techniques have limitations in establishing their impact at the molecular level. In this review, we discuss how molecular dynamic simulations have been employed to characterize the surface phenomenon in the enzyme immobilization procedure, in an attempt to decipher its impact on the enzyme features, such as activity and stability. In particular, computational studies on the immobilization of enzymes using i) nanoparticles, ii) self-assembled monolayers, iii) graphene and carbon nanotubes, and iv) other surfaces are covered. Importantly, this thorough literature survey reveals that, while simulations have been primarily performed to rationalize the molecular aspects of the immobilization event, their use to predict adequate protocols that can control its impact on the enzyme properties is, up to date, mostly missing.

Microfluidic devices have attracted much attention in the current day owing to the unique advantages they provide. However, their application for industrial use is limited due to manufacturing limitations and high cost. Moreover, the scaling-up process of the microreactor has proven to be difficult. Three-dimensional (3D) printing technology is a promising solution for the above obstacles due to its ability to fabricate complex structures quickly and at a relatively low cost. Hence, combining the advantages of the microscale with 3D printing technology could enhance the applicability of microfluidic devices in the industrial sector. In the present work, a 3D-printed single-channel immobilized enzyme microreactor with a volume capacity of 30 μL was designed and created in one step via the fused deposition modeling (FDM) printing technique, using polylactic acid (PLA) as the printing material. The microreactor underwent surface modification with chitosan, and β-glucosidase from Thermotoga maritima was covalently immobilized. The immobilized biocatalyst retained almost 100% of its initial activity after incubation at different temperatures, while it could be effectively reused for up to 10 successful reaction cycles. Moreover, a multi-channel parallel microreactor incorporating 36 channels was developed, resulting in a significant increase in enzymatic productivity.

The escalating demand for processed foods has led to the widespread industrial use of glucose isomerase (GI) for high-fructose corn syrup (HFCS) production. This reliance on GIs necessitates continual Co2+ supplementation to sustain high catalytic activity across multiple reaction cycles. In this study, Serratia marcescens GI (SmGI) was immobilized onto surfaces of the metal-organic framework (MOF) material MOF (Co)-525 to generate MOF (Co)-525-GI for use in catalyzing glucose isomerization to generate fructose. Examination of MOF (Co)-525-GI structural features using scanning electron microscopy-energy dispersive spectroscopy, Fourier-transform infrared spectroscopy, and ultraviolet spectroscopy revealed no structural changes after SmGI immobilization and the addition of Co2+. Notably, MOF (Co)-525-GI exhibited optimal catalytic activity at pH 7.5 and 70 °C, with a maximum reaction rate (Vmax) of 37.24 ± 1.91 μM/min and Km value of 46.25 ± 3.03 mM observed. Remarkably, immobilized SmGI exhibited sustained high catalytic activity over multiple cycles without continuous Co2+ infusion, retaining its molecular structure and 96.38% of its initial activity after six reaction cycles. These results underscore the potential of MOF (Co)-525-GI to serve as a safer and more efficient immobilized enzyme technology compared to traditional GI-based food-processing technologies.

Metal–organic framework materials (MOFs) and their derivatives are considered ideal immobilization carrier materials because of their large specific surface area, high porosity and excellent structural designability. Among them, ZIF-8 has great potential for immobilization of enzymes due to mild synthesis conditions, and good biocompatibility. However, conventional ZIF-8 crystals have poor separation and recovery efficiency due to their small pore size and poor acid stability, greatly limiting their application in enzyme immobilization and further application. Although the carbonization of ZIF-8 by pyrolysis has been shown to be one of the approaches that can enhance its chemical stability, this still does not effectively solve the problem of the difficulty of recycling. Herein, we developed a strategy of pre-carbonization immersion (immersion in aqueous FeSO4 solution before carbonization) to synthesize ordered macroporous ZIF-8-derived carbon materials with stable ferromagnetism (denoted as CZ-x-M-y, where x denotes the carbonization temperature and y denotes the concentration of the impregnated FeSO4 solution) and used them to immobilize lipases for biodiesel production. XRD analysis showed that the magnetic properties in the materials came from Fe3C species. We found that the magnetic carbon materials obtained by carbonization at 600 °C showed the best immobilization effect, where CZ-600-M-0.3 (using 0.3 mol·L−1 FeSO4 aqueous solution to soak ZIF-8 and carbonized at 600 °C) had the highest enzyme loading of 183.04 mg·g−1, which was 49.7% higher than that of the non-magnetic CZ-600. In addition, CZ-600-M-0.5 maintained the highest enzyme activity, which was 81.9% of the initial activity, after five batches of reuse. The stable magnetic support materials reported in this study have promising potential for the industrial application of immobilized lipase.

Ionic additives affect the structure, activity and stability of lipases, which allow for solving common application challenges, such as preventing the formation of protein aggregates or strengthening enzyme–support binding, preventing their desorption in organic media. This work aimed to design a biocatalyst, based on lipase improved by the addition of ionic additives, applicable in the production of ethyl esters of fatty acids (EE). Industrial enzymes from Thermomyces lanuginosus (TLL), Rhizomucor miehei (RML), Candida antárctica B (CALB) and Lecitase®, immobilized in commercial supports like Lewatit®, Purolite® and Q-Sepharose®, were tested. The best combination was achieved by immobilizing lipase TLL onto Q-Sepharose® as it surpassed, in terms of %EE (70.1%), the commercial biocatalyst Novozyme® 435 (52.7%) and was similar to that of Lipozyme TL IM (71.3%). Hence, the impact of ionic additives like polymers and surfactants on both free and immobilized TLL on Q-Sepharose® was assessed. It was observed that, when immobilized, in the presence of sodium dodecyl sulfate (SDS), the TLL derivative exhibited a significantly higher activity, with a 93-fold increase (1.02 IU), compared to the free enzyme under identical conditions (0.011 IU). In fatty acids ethyl esters synthesis, Q-SDS-TLL novel derivatives achieved results similar to commercial biocatalysts using up to ~82 times less enzyme (1 mg/g). This creates an opportunity to develop biocatalysts with reduced enzyme consumption, a factor often associated with higher production costs. Such advancements would ease their integration into the biodiesel industry, fostering a greener production approach compared to conventional methods.

The present work is a review of the research on using hydrogels based on natural biodegradable polymers, starch, and gelatin for enzyme immobilization. This review addresses the main properties of starch and gelatin that make them promising materials in biotechnology for producing enzyme preparations stable during use and storage and insensitive to chemical and physical impacts. The authors summarize their achievements in developing the preparations of enzymes immobilized in starch and gelatin gels and assess their activity, stability, and sensitivity for use as biorecognition elements of enzyme inhibition-based biosensors.

Electrophoretic deposition is a powerful tool for depositing materials onto a substrate by using an electric field; its application in biotechnological areas, namely, electrophoretic protein deposition (EPD), is the most promising for, e.g., fabricating novel amperometric biosensors. Unfortunately, EPD suffers from several drawbacks due to coupled parasite electrochemical processes damaging the deposit; moreover, the nature of the deposition process, the deposit, and its stability are still controversial and unknown. The present research presents a deep investigation of the EPD processes conducted by using several electroanalytical techniques and an electrochemical quartz crystal microbalance (EQCM); notably, EPD was used here as a novel tool for performing an electrophoretically assisted, classical enzyme immobilization technique like co-crosslinking, thus permitting the immobilization of the desired protein in situ, i.e., exclusively onto the deposition electrode. An electrochemical study permitted the acquisition of useful insights about electrophoresis processes as well as solvent discharge and gas evolution at the deposition electrode; further, the use of appropriate current or potential pulse sequences, as investigated and improved in this study, together with fine-tuned chemical conditions, allowed the optimization of this novel EPD approach. Moreover, an EQCM study gave useful insights into the kinetics of the process, permitting a quantitative estimate of the deposit.

This article provides a method to upgrade epoxy-functionalized carriers for covalent enzyme immobilization to selective carriers suitable for covalent immobilization of metal affinity-tagged enzymes without the need of preliminary enzyme purification. Affinity function doping of the epoxy-functionalized surface introduces an advanced possibility to avoid the costly and time-consuming downstream processes required for efficient immobilization on non-selective epoxy carriers. Our approach is based on the partial functionalization of surface epoxides via a proper diamine-derived linker and an ethylenediaminetetraacetic dianhydride-based chelator charged with cobalt ions. The solid macroporous carriers, doped with metal affinity functions, have both coordinative binding ability (rapid anchoring the metal affinity-tagged enzymes to the surface) and subsequent covalent bond-forming ability (preferred binding of the tagged enzyme to the surface after proper washing by the residual epoxide functions), enabling a single operation for the enrichment and immobilization of a recombinant phenylalanine ammonia-lyase from parsley fused to a polyhistidine affinity tag. The immobilized PcPAL was applied in the ammonia elimination of racemic phenylalanine, 4-chlorophenylalanine, and 4-bromophenylalanine to produce the corresponding d-phenylalanines, in addition to the formation of (E)-cinnamates, as well as in ammonia addition reactions to (E)-cinnamates, yielding the corresponding enantiopure l-phenylalanines.

In this paper, the immobilization of lipase from Candida rugosa on hydrophilic Na-montmorillonite (MT) and hydrophobic modified montmorillonite (MTS) is investigated. Hydrophobic MTS was prepared by changing the nature of hydrophilic MT with cetrimonium bromide surfactant. The enzymatic activity of lipase immobilized on Na-montmorillonite (LMT) and lipase immobilized on modified montmorillonite (LMTS) was investigated in the production of biodiesel from waste cooking oil. The support modification and enzyme immobilization were evaluated by BET, XRD, and SEM techniques. The effects of temperature, time, water content, and the molar ratio of methanol to oil on biodiesel yield were also investigated. The results showed that the activity of LMTS was much better than LMT. Under optimal conditions, the biodiesel yield produced by LMTS was about 86.4%. LMTS showed good storage stability, and after 30 days of storage at 4 ℃, the biodiesel yield was about 64.2%, while the biodiesel yield of free lipase (FL) was about 57.1%. In addition, LMTS had good reusability compared to LMT, and the biodiesel yield after 10 cycles was about 51.6%.

Abstract Over the past decades, there has been an escalating rise in the need for chemicals and catalytic materials to keep up with global demands. Addressing those issues by conventional methods often becomes inefficient, with myriad operational risks. Process intensification methods through procedural and equipment‐based modifications have been considered greener, have higher heat and mass transfer rates, and operate with lower costs. In this review, research using ultrasonic reactors and microreactors, along with developments through an integrated external energy source, for synthesizing acrylic microspheres is covered extensively. Acrylic microspheres have garnered much interest for their biocompatibility, affinity toward functionalization, and wide range of applications. Core–shell, composite, functional‐group modified, and porous acrylic microspheres are used for enzyme immobilization and as catalyst carriers. The use of acrylic support has provided huge improvements in catalytic activity, reusability, recyclability, and overall stability. Finally, various other process intensification methods and alternate support materials are covered to help enhance future developments in the field of catalysis.

The application of phenylalanine ammonia lyases (PALs) for the amination of a variety of cinnamic acids has been shown to be a cost-efficient method to produce a variety of phenylalanine analogues. Nonetheless, as many other biocatalytic tools, the process intensification, especially due to the high equivalents of ammonia needed, and the cost-efficiency of the catalyst production and use have been key points to further prove their usefulness. Here, we investigated the use of previously characterized PALs (AvPAL and PbPAL) for the amination of a series of substituted cinnamic acids. To enhance the process scalability and the reusability of the catalyst, we investigated the use of covalent immobilization onto commercially available supports, creating a heterogeneous catalyst with good recovered activity (50%) and excellent stability. The immobilized enzyme was also incorporated in continuous flow for the synthesis of 3-methoxy-phenyl alanine and 4-nitro-phenylalanine, which allowed for shorter reaction times (20 min of contact time) and excellent conversions (88% ± 4% and 89% ± 5%) respectively, which could be maintained over extended period of time, up to 24 h. This work exemplifies the advantages that the combination of enzyme catalysis with flow technologies can have not only in the reaction kinetics, but also in the productivity, catalyst reusability and downstream processing.

The modification of membranes with polyelectrolytes via the Layer-by-Layer (LBL) method has become state of the art in recent years. It is used to fabricate nanofiltration hollow fiber membranes or to immobilize biomolecules on a membrane surface. However, it still remains a time consuming process. In contrast, this work explores a single-step membrane modification with coating solutions containing both polyanions and polycations. High salt concentration in the coating solution suppresses the complexation of the polyelectrolytes prior to the coating. Then, the controlled reduction of the salt concentration during the coating triggers the formation of a polyelectrolyte complex layer on the membrane. Three coating methods are proposed: (1) In interfacial complexation (IC), the polyelectrolyte solution coats the membrane and is subsequently precipitated by flushing with water. (2) Diffusive desalination (DDS) uses the concentration difference between the coating solution in the lumen and a water stream in the shell side to remove salt ions continuously. (3) In polyelectrolyte concentration (PC), the polyelectrolyte solution is coated at a constant flux. Here, the membrane retains the polyelectrolyte while ions permeate through. First, we evaluate the coating methods regarding their ability to produce nanofiltration membranes, which varies depending on the coating method used. With PC, membranes with up to 79% MgCl2 rejection and a permeability of 30 LMH/bar are obtained. Moreover, in-situ functionalization of the membranes is investigated by the addition of enzymes. Here, with DDS enzymes are immobilized, mostly achieved through adsorption via electrostatic interactions.

Flow biocatalysis is a key enabling technology that is increasingly being applied to a wide array of reactions with the aim of achieving process intensification, better control of biotransformations, and minimization of waste stream. In this mini-review, selected applications of flow biocatalysis to the preparation of food ingredients, APIs and fat- and oil-derived commodity chemicals, covering the period 2020-2022, are described.

An immobilized lipase with metal‐organic frameworks (MOFs) was first used for the kinetic resolution of mandelic acid enantiomers by transesterification reaction using vinyl acetate as acyl donor in organic medium. Notably, the biocompatibility of the carrier and catalytic performance of lipase could be significantly improved via modification of NH2‐Ni‐MOF with polyvinylpyrrolidone. After extensively screening the enzymatic process, the optimal enantioselective resolution conditions and excellent outcomes were obtained for the enzyme‐catalyzed transesterification reaction. In addition, the recovered immobilized lipase displayed outstanding reusability after immobilization. [ABSTRACT FROM AUTHOR]

In recent decades, enzyme-based biocatalytic systems have garnered increasing interest in industrial and applied research for catalysis and organic chemistry. Many enzymatic reactions have been applied to sustainable and environmentally friendly production processes, particularly in the pharmaceutical, fine chemicals, and flavor/fragrance industries. However, only a fraction of the enzymes available has been stepped up towards industrial-scale manufacturing due to low enzyme stability and challenging separation, recovery, and reusability. In this context, immobilization and co-immobilization in robust support materials have emerged as valuable strategies to overcome these inadequacies by facilitating repeated or continuous batch operations and downstream processes. To further reduce separations, it can be advantageous to use multiple enzymes at once in one pot. Enzyme co-immobilization enables biocatalytic synergism and reusability, boosting process efficiency and cost-effectiveness. Several studies on multi-enzyme immobilization and co-localization propose kinetic advantages of the enhanced turnover number for multiple enzymes. This review spotlights recent progress in developing versatile biocatalytic cascade systems by multi-enzyme co-immobilization on environmentally friendly biopolymers and nanostructured materials and their application scope in the chemical and biotechnological industries. After a succinct overview of carrier-based and carrier-free immobilization/co-immobilizations, co-immobilization of enzymes on a range of biopolymer and nanomaterials-based supports is thoroughly compiled with contemporary and state-of-the-art examples. This study provides a new horizon in developing effective and innovative multi-enzymatic systems with new possibilities to fully harness the adventure of biocatalytic systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • The recent advances in the immobilization of enzymes based on hierarchical NFs was reviewed. • The application of enzymes-inorganic hNFs was summarized. • The information on metrics regarding catalytic performance of the enzymes-inorganic hNFs was comprehensive discussed. In general, enzyme immobilization technologies were applied for seeking to create reusable enzymes with improved enzyme properties for industrial applications. However, to traditional immobilization technologies, such as adsorption, covalent binding, cross-linking, and entrapment, the reusability and stability are improved, the activity is often obviously reduced compared with the free enzyme. To resolve this challenge, the recently appeared hierarchical Nanoflowers (NFs) technology opened a new door for enzyme immobilization, which possesses the inherent merits such as enhanced loading capacity and high specific surface area. Recent researches have clearly stated that it is an inexpensive and environmentally benign technology for enzyme immobilization. In this review, we focus on the recent advances in the immobilization of enzymes with the environmentally benign hierarchical NFs, as well as their application. [ABSTRACT FROM AUTHOR]

Biocatalytic syntheses often require unfavorable conditions, which can adversely affect enzyme stability. Consequently, improving the stability of biocatalysts is needed, and this is often achieved by immobilization. In this study, we aimed to compare the stability of soluble and immobilized transaminases from different species. A cysteine in a consensus sequence was converted to a single aldehyde by the formylglycine-generating enzyme for directed single-point attachment to amine beads. This immobilization was compared to cross-linked enzyme aggregates (CLEAs) and multipoint attachments to glutaraldehyde-functionalized amine- and epoxy-beads. Subsequently, the reactivity and stability (i.e., thermal, storage, and solvent stability) of all soluble and immobilized transaminases were analyzed and compared under different conditions. The effect of immobilization was highly dependent on the type of enzyme, the immobilization strategy, and the application itself, with no superior immobilization technique identified. Immobilization of HAGA-beads often resulted in the highest activities of up to 62 U/g beads, and amine beads were best for the hexameric transaminase from Luminiphilus syltensis. Furthermore, the immobilization of transaminases enabled its reusability for at least 10 cycles, while maintaining full or high activity. Upscaled kinetic resolutions (partially performed in a SpinChemTM reactor) resulted in a high conversion, maintained enantioselectivity, and high product yields, demonstrating their applicability. [ABSTRACT FROM AUTHOR]

Glycoside hydrolases (GHs) exhibit high activity and stability under harsh conditions, such as high temperatures and extreme pHs, given their wide use in industrial biotechnology. However, strategies for improving the acidophilic and alkalophilic adaptations of GHs are poorly summarized due to the complexity of the mechanisms of these adaptations. This review not only highlights the adaptation mechanisms of acidophilic and alkalophilic GHs under extreme pH conditions, but also summarizes the recent advances in engineering the pH performances of GHs with a focus on four strategies of protein engineering, enzyme immobilization, chemical modification, and medium engineering (additives). The examples described here summarize the methods used in modulating the pH performances of GHs and indicate that methods integrated in different protein engineering techniques or methods are efficient to generate industrial biocatalysts with the desired pH performance and other adapted enzyme properties. [ABSTRACT FROM AUTHOR]

Enzyme immobilization can improve the catalytic activity and stability against temperature, pH, and various environmental conditions. In this study, carboxyl-functionalized chitosan-coated magnetic nanoparticle was synthesized and used as a support for the immobilization of laccase. The synthesized nanoparticle was characterized by transmission electron microscopy and FT-IR spectroscopy. In order to investigate the stability of the enzyme to pH changes, the activities of free and immobilized enzymes were measured at different pH values ranging from 2.0 to 8.0. The thermal stability and storage stability of the enzymes were also studied. Kinetic parameters and reusability were evaluated for both free and immobilized enzymes. The results showed that the magnetic nanoparticles and carboxyl-functionalized chitosan-coated magnetic nanoparticles are spherical with dispersed size distribution and zeta-potential of − 33.4 and + 1.95 mV, respectively. Based on our observations, the maximum activity of the enzyme was shifted toward higher temperatures after the immobilization. Furthermore, the immobilized laccase retained 80% of its initial activity after 120 days, while free enzyme maintained only 50% of its initial activity during the same period. The values of Michealis-Menten constant and maximum velocity for immobilized laccase were 0.113 mM and 1.27 µM min−1, respectively, whereas the values for free enzyme were 0.093 mM and 1.79 µM min−1, respectively. Both free and immobilized laccase exhibited optimum activities at pH 3.0 and decreasing trends were found at pH values more than 5 but immobilized laccase preserved its high activity at a wide range of pH compared with that of free laccase. In particular, it can be used at higher temperatures and broader pH with improved storage stability and reusability, demonstrating the superior potential of bioremediation utilizing this immobilization method. [ABSTRACT FROM AUTHOR]

Immobilization depicts a propitious route to optimize the catalytic performances, efficient recovery, minimizing autocatalysis, and also augment the stabilities of enzymes, particularly in unnatural environments. In this opinion, supramolecules and multimolecular frameworks have captivated immense attention to achieve profound controllable interactions between enzyme molecules and well‐defined natural or synthetic architectures to yield protein bioconjugates with high accessibility for substrate binding and enhanced enantioselectivities. This scholastic review emphasizes the possibilities of associating multimolecular complexes with biological entities via several types of interactions, namely covalent interactions, host–guest complexation, π−π ${\rm{\pi }}-{\rm{\pi }}$ interactions, intra/inter hydrogen bondings, electrostatic interactions, and so forth offers remarkable applications for the modulations of enzymes. The potential synergies between artificial supramolecular structures and biological systems are the primary concern of this pedagogical review. The majority of the research primarily focused on the dynamic biomolecule‐responsive supramolecular assemblages and multimolecular architectures as ideal platforms for the recognition and modulation of proteins and cells. Embracing sustainable green demeanors of enzyme immobilizations in a quest to reinforce site‐selectivity, catalytic efficiency, and structural integrality of enzymes are the contemporary requirements of the biotechnological sectors that instigate the development of novel biocatalytic systems. [ABSTRACT FROM AUTHOR]

Immobilizing enzymes within metal-organic frameworks (MOFs) enables enzymes to against extreme environments. However, these MOF shells are just like armors, protective but heavy, which shield the enzymes from threats while locking them in the cage. The exploitation of immobilization strategy and intrinsic property of MOFs themselves is of great significance. Here, we proposed a functional protein trap strategy for efficient enzyme encapsulation. The ferrocenedicarboxylic acid (Fc) was used to induce the formation of defect-rich Co-based MOFs (CoBDC-Fc). As result, the engineered protein trap can not only improve the enzyme loading but also accelerate catalytic efficiency. Specifically, the atomically dispersed Fc sites serve as cocatalysts/cofactors and even change the conformation of enzymes in the construed microenvironment. Furthermore, the obtained CoBDC-Fc/enzyme exhibits excellent recyclability and tolerance to inhospitable conditions. Benefited by these, the CoBDC-Fc/enzyme/antigen composites were further prepared for cascade enzyme-linked immunosorbent assay of prostate-specific antigen with satisfactory sensitivity. [ABSTRACT FROM AUTHOR]

Acetylcholinesterase (AChE; EC 3.1.1.7) is a group of enzymes that catalyzes the hydrolysis of the neurotransmitter acetylcholine (ACh) into choline and acetate. AChE inhibition is commonly utilized as a biomarker for pesticides. In membrane based AChE biosensors the enzyme immobilization onto an electrode surface is of prime importance. In previous studies, conducting polymers-based supports have been used for the immobilization of AChE. In this study, a novel immobilization platform was developed. The simultaneous polymerization of pyrrole and functional thiol/ene monomers was performed to prepare conductive thermosets. AchE was covalently immobilized onto the membranes through the epoxy functional groups. After the immobilization process, the optimal temperature increased to 50 °C, displaying a better thermal stability and the optimum pH was elevated to 8.5. The activity of the immobilized enzyme was tested in the presence of several metals, and it was found that Cu2+ ions caused a noticable inhibition. After 10 cycles, the immobilized enzyme retained 51% of its original activity. In accordance with our results; the durability and the stability of the immobilized enzyme were improved. In future studies, the method applied here can be used in the design of an AchE biosensor. [ABSTRACT FROM AUTHOR]

The urgent demand for alternative energy sources has been sparked by the tremendous burden on fossil fuels and the resulting acute energy crisis and climate change issues. Lignocellulosic biomass is a copious renewable and alternative bioresource for the generation of energy fuels and biochemicals in biorefineries. Different pretreatment strategies have been established to overcome biomass recalcitrance and face technological challenges, such as high energy consumption and operational costs and environmental hazards, among many. Biological pretreatment using microbial enzymes is an environmentally benign and low-cost method that holds promising features in the effective pretreatment of lignocellulosic biomass. Due to their versatility and eco-friendliness, cellulases, hemicellulases, and ligninolytic enzymes have been recognized as "green biocatalysts" with a myriad of industrial applications. The current review provides a detailed description of different types of lignocellulolytic enzymes, their mode of action, and their prospective applications in the valorization of lignocellulosic biomass. Solid state fermentation holds great promise in the microbial production of lignocellulolytic enzymes owing to its energy efficient, environment friendly, and higher product yielding features utilizing the lignocellulosic feedstocks. The recent trends in the application of enzyme immobilization strategies for improved enzymatic catalysis have been discussed. The major bottlenecks in the bioprocessing of lignocellulosic biomass using microbial enzymes and future prospects have also been summarized. [ABSTRACT FROM AUTHOR]

DNA-based biomimetic enzymes have attracted extensive attention due to their unique structure and stability compared to natural enzymes. Meanwhile, the specific sequences of DNA itself also have a catalytic effect. Herein, we first designed three guanine-rich DNA sequences numbered c−Myc3c, PG4TC, and TTT to construct g−quadruplex/hemin DNAzymes. Then, the g−quadruplex/hemin DNAzymes with the best activity were selected by a comprehensive examination of activity, degradation rate, and affinity. Subsequently, the stability and reusability of UiO66−DNAzymes were investigated using UiO66 as the carrier to immobilize DNAzymes. The results showed that UiO66−DNAzymes had excellent reusability and stability. Finally, UiO66−DNAzymes were successfully used for glucose detection by cascading with glucose oxidase (GOx) with a detection limit of 0.62 μM. The constructed glucose sensor had a good specificity, which is of great significance for developing a novel, accurate, fast, and economical glucose detection sensor. [ABSTRACT FROM AUTHOR]

Immobilization of lipase AK from Pseudomonas fluorescens onto a microsphere support constructed by the metal organic framework (MOF) of NH 2 -Co-MOF was investigated. The loading capacity of 256.9 mg/g (MOF) with an immobilization yield of 72.3% was achieved. The further investigation demonstrated that AK@NH 2 -Co-MOF was an efficient catalyst in enantiospecific transesterification of 1-(4-bromophenyl) ethanol (BPE) with vinyl acetate, where the expressed activity of (4.028 ± 0.21)× 10−2 mmol/(min·mg AK@NH 2 -Co-MOF) was 8 times higher than the free lipase. Under the optimum conditions, BPE enantiomers were resolved by AK@NH 2 -Co-MOF with conversion of 50.42%, enantiomeric excess > 99% for remaining substrate (ee s) and enantiomeric excess > 99 % for product (ee p). AK@NH 2 -Co-MOF is recyclable and 51.62 % of the initial conversion was retained after 5 cycles of reuse. NH 2 -Co-MOF is promising for enzyme immobilization and the prepared AK@NH 2 -Co-MOF exhibited great potential for efficient biosynthesis of optically pure BPE. [Display omitted] • Covalent linkage of Pseudomonas fluorescens lipase to metal organic framework support. • Sought after products obtained in more than 99 % optical purity. • Enhanced activity as compared to the commercial lipase preparation. • Immobilized lipase reaches optimal parameters in half the time than free lipase. • Biocatalyst retains 52 % of initial conversion after 5 cycles of reuse. [ABSTRACT FROM AUTHOR]

Lipase immobilization has been widely studied because it allows for enzyme reuse and provides more assertive control over the catalytic process. This study aimed to evaluate the effect of bead size on the performance of entrapped lipase. Eversa® Transform 2.0 was immobilized on calcium alginate beads by jet cutting and dripping. Beads produced by jet cutting were small (D[34] = 803.36 ± 16.9 µn) and had a relatively narrow size distribution (span of 0.79). Beads obtained by extrusion dripping measured 2459.98 ± 15.6 pm and had a span of 0.45. Infrared spectroscopy and microscopic analysis confirmed the presence of lipase in both types of beads. Lipase showed high hydrolytic activity in its free form (15,000 U g-1. Immobilization in calcium alginate was effective but decreased recovered enzyme activity. The porosity of loaded beads varied with size. The high surface area (5.46 vs 3.13 m² g-1) and porosity (76.33% vs 21.65%) of beads produced by jet cutting, as compared with those produced by dripping, favored enzyme activity (3000 vs 1500 U g-1 protein). The results indicate that facilitated mass transfer is an important factor in the development of immobilized enzymes. [ABSTRACT FROM AUTHOR]

Phenol, a pollutant frequently found in chemical industries effluents, is highly toxic even in low concentrations. This study reports a green, simple, and rapid method for qualitative phenol biosensing using horseradish peroxidase (HRP) hybrid nanoflowers made with copper (Cu2+-hNF) or calcium (Ca2+-hNF) ions. The enzyme was immobilized through protein-inorganic self-assembly into hybrid structures and subsequently supported onto a polyvinylidene fluoride (PVDF) membrane. SEM, EDS, FTIR, and XRD techniques sustained the effective enzyme encapsulation into hybrid structures. The protein concentration in the structures was 0.25 mg.mL−1 for both ions. The best temperature and pH were 60 °C and 7.4, respectively, for both hybrids and the free enzyme, suggesting that the immobilization did not affect the optimal conditions of the free HRP. Thermal stability from 25 to 70 °C and pH stability from 4.0 to 9.0 of the hybrids were also determined. Finally, using copper and calcium hybrids, both biosensors produced onto a PVDF membrane could detect phenol in concentrations ranging from 0.72 to 24.00 µmol.mL−1 in 1 min. In contrast, control biosensors produced with free enzyme have not presented a visible color change in the same conditions. The findings suggest a promising application of the developed biosensors in functional phenol detection. [ABSTRACT FROM AUTHOR]

This review provides a general overview of different biosensors, mostly concentrating on electrochemical analytical devices, while briefly explaining general approaches to various kinds of biosensors, their construction and performance. A discussion on how all required components of biosensors are brought together to perform analytical work is offered. Different signal-transducing mechanisms are discussed, particularly addressing the immobilization of biomolecular components in the vicinity of a transducer interface and their functional integration with electronic devices. The review is mostly addressing general concepts of the biosensing processes rather than specific modern achievements in the area. [ABSTRACT FROM AUTHOR]

All the disciplines of science, especially biotechnology, have given continuous attention to the area of enzyme immobilization. However, the structural support made by material science intervention determines the performance of immobilized enzymes. Studies have proven that nanostructured supports can maintain better catalytic performance and improve immobilization efficiency. The recent trends in the application of nanofibers using natural polymers for enzyme immobilization have been addressed in this review article. A comprehensive survey about the immobilization strategies and their characteristics are highlighted. The natural polymers, e.g., chitin, chitosan, silk fibroin, gelatin, cellulose, and their blends with other synthetic polymers capable of immobilizing enzymes in their 1D nanofibrous form, are discussed. The multiple applications of enzymes immobilized on nanofibers in biocatalysis, biosensors, biofuels, antifouling, regenerative medicine, biomolecule degradation, etc.; some of these are discussed in this review article. [ABSTRACT FROM AUTHOR]

Enzyme immobilization is a powerful strategy for enzyme stabilization and recyclability. Materials covered with multipoint molecules are very attractive for this goal, since the number of active moieties to attach the enzyme increases with respect to monofunctional linkers. This work evaluates different dendrimers supported on silica to immobilize a protease enzyme, Alcalase. Five different dendrimers were employed: two carbosilane (CBS) dendrimers of different generations (SiO2-G0Si-NH2 and SiO2-G1Si-NH2), a CBS dendrimer with a polyphenoxo core (SiO2-G1O3-NH2), and two commercial polyamidoamine (PAMAM) dendrimers of different generations (SiO2-G0PAMAM-NH2 and SiO2-G1PAMAM-NH2). The results were compared with a silica support modified with a monofunctional molecule (2-aminoethanethiol). The effect of the dendrimer generation, the immobilization conditions (immobilization time, Alcalase/SiO2 ratio, and presence of Ca2+ ions), and the digestion conditions (temperature, time, amount of support, and stirring speed) on Alcalase activity has been evaluated. Enzyme immobilization and its activity were highly affected by the kind of dendrimer and its generation, observing the most favorable behavior with SiO2-G0PAMAM-NH2. The enzyme immobilized on this support was used in two consecutive digestions and, unlike CBS supports, it did not retain peptides released in the digestion. [ABSTRACT FROM AUTHOR]

Hydrogen gas, a carbon-free energy carrier, can be produced via fossil fuel reforming, coal gasification, water electrolysis, photocatalysis, or biological process. Biohydrogen production from lignocellulosic biomass (LCB) in this regard, appears as an environmental benign, sustainable, non-food competing second generation fuel. LCB serves as the largest potential carbon source for sustainable biohydrogen production with an enormous global annual capacity of more than one trillion tons. Enzymes in this case, are widely used to hydrolyse the LCB into fermentable sugars, and subsequent hydrogen production is carried out by dark fermentation. However, the untapped non-food competing LCB is currently impeded by several critical bottlenecks including sensitivity of cells and enzymes to numerous denaturing conditions, recyclability, and high cost of enzyme. Low productivity of hydrolysis and hydrogen production in this regard, lead to a larger bioreactor and capital expenditures (CAPEX) requirement, which in turn, making this approach to be less competitive in commercial application. These bottlenecks can be overcome by immobilization technique, which enables the recyclability, improves stability and productivity of the enzyme and cells. Current review accommodates for the important outlook and critical insights into the immobilization techniques, providing important guidelines for the operation of immobilization techniques to elevate commercial competitiveness of biohydrogen production from LCB in the future. The effect of geometry, surface charges, and wettability of different type of carriers for cell immobilization to enhance biohydrogen production are discussed. The critical aspects of the immobilization parameters, such as temperature, pH, and duration which could significantly affect the properties of immobilized enzymes are thoroughly examined in this review. Suggestions and future directions of this field are provided to assist the development of an efficient, economic, and sustainable hydrogen production process. • Lignocellulose is a potential feedstock for dark fermentative biohydrogen production. • Cell and enzyme immobilization techniques aid in LCB conversion to improve biohydrogen yield. • The synergism between the cells and carriers affect the immobilization efficiency. • Enzyme immobilization enhances the stability and reusability of enzyme to produce simple sugars. [ABSTRACT FROM AUTHOR]

The worldwide increase in metropolitan cities and rise in industrialization have resulted in the assimilation of hazardous pollutants into the ecosystems. Different physical, chemical and biological techniques have been employed to remove these toxins from water bodies. Several bioprocess applications using microbes and their enzymes are utilized to achieve the goal. Biocatalysts, such as laccases, are employed explicitly to deplete a variety of organic pollutants. However, the degradation of contaminants using biocatalysts has many disadvantages concerning the stability and activity of the enzyme. Hence, they are immobilized on different supports to improve the enzyme kinetics and recyclability. Furthermore, standard wastewater treatment methods are not effective in eliminating all the contaminants. As a result, membrane separation technologies have emerged to overcome the limitations of traditional wastewater treatment methods. Moreover, enzymes immobilized onto these membranes have generated new avenues in wastewater purification technology. This review provides the latest information on laccases from diverse sources, their molecular framework and their mode of action. This report also gives information about various immobilization techniques and the application of membrane bioreactors to eliminate and biotransform hazardous contaminants. In a nutshell, laccases appear to be the most promising biocatalysts for green and cost-efficient wastewater treatment technologies. [ABSTRACT FROM AUTHOR]

Filamentous microorganisms are used as molecular factories in industrial biotechnology. In 2007, a new approach to improve productivity in submerged cultivation was introduced: microparticle‐enhanced cultivation (MPEC). Since then, numerous studies have investigated the influence of microparticles on the cultivation. Most studies considered MPEC a morphology engineering approach, in which altered morphology results in increased productivity. But sometimes similar morphological changes lead to decreased productivity, suggesting that this hypothesis is not a sufficient explanation for the effects of microparticles. Effects of surface chemistry on particles were paid little attention, as particles were often considered chemically‐inert and bioinert. However, metal oxide particles strongly interact with their environment. This review links morphological, physical, and chemical properties of microparticles with effects on culture broth, filamentous morphology, and molecular biology. More precisely, surface chemistry effects of metal oxide particles lead to ion leaching, adsorption of enzymes, and generation of reactive oxygen species. Therefore, microparticles interfere with gene regulation, metabolism, and activity of enzymes. To enhance the understanding of microparticle‐based morphology engineering, further interactions between particles and cells are elaborated. The presented description of phenomena occurring in MPEC eases the targeted choice of microparticles, and thus, contributes to improving the productivity of microbial cultivation technology. [ABSTRACT FROM AUTHOR]

As a new environmentally friendly and sustainable green solvent, deep eutectic solvent (DES) was considered to be the most suitable alternative solvent for ionic liquids, with wide application. In this study, we reported a novel method of the synthesis of Fe3O4 nanoparticles (Nano-Fe3O4) in the natural deep eutectic solvent (NADES) of betaine/urea. Compared with traditional synthetic methods, this method of synthesising magnetic nanoparticles with the NADES as solvent possesses the superiority of mild reaction conditions, no need for nitrogen protection and short time-consuming. The yield of Nano-Fe3O4 synthesised in the NADES was as high as 94.9%. The synthesised Nano-Fe3O4 were coated with silicon and used to immobilise β-glucosidase extracted from Agrocybe aegerit. The results showed that the immobilisation efficiency of the β-glucosidase was 87.5% and the immobilisation yield was 86.2%. The optimum reaction conditions of the immobilised β-glucosidase were 55 °C and pH 6.0. In addition, the thermostability, pH stability and storage stability of the β-glucosidase were greatly improved after its immobilisation on the Nano-Fe3O4. After reused for 10 cycles, the residual activity of the immobilised β-glucosidase was still more than 72.4%. From multiple perspectives, the synthesised Nano-Fe3O4 in the NADES seems to be an excellent carrier for enzyme immobilisation. [ABSTRACT FROM AUTHOR]