Nanotechnology is an area that has been growing over the years, being possible nowadays to find numerous materials constructed at nanoscale. In addition, many applications have been attributed to ...these "new" materials. In this review is presented a brief overview of nanoparticles used for the immobilization of enzymes. Considering the extensive universe of immobilization in nanoparticles, some were chosen to be exposed here, such as chitosan, graphene, silica, polymers, magnetic, nanoflowers, among others. Advantages, disadvantages and limitations of nanoimmobilization also be discussed. Some applications of nanoimmobilized enzymes are presented, like as biodiesel, flavor synthesis ester and biosensors. The purpose of this paper is to provide an overview of what is being studied in relation to nanoparticles for enzymes immobilization, and some discussions about them, aimed at assisting researchers in future studies and reviews.
Advantages, drawbacks and trends in nanomaterials for enzyme immobilization.
•The improvement of food bioprocess, from the safety point of view, was proposed.•Chitosan particles were prepared and crosslinked with genipin and β-galactosidase.•Chitosan–genipin particles were ...more resistant than chitosan–glutaraldehyde particles.•Effective lactose conversion and synthesis of GOS using a non-toxic biocatalyst.
In order to develop safer processes for the food industry, we prepared a chitosan support with the naturally occurring crosslinking reagent, genipin, for enzyme. As application model, it was tested for the immobilization of β-d-galactosidase from Aspergillus oryzae. Chitosan particles were obtained by precipitation followed by adsorption of the enzyme and crosslinking with genipin. The particles were characterized by Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The immobilization of the enzyme by crosslinking with genipin provided biocatalysts with satisfactory activity retention and thermal stability, comparable with the ones obtained with the traditional methodology of immobilization using glutaraldehyde. β-d-Galactosidase–chitosan–genipin particles were applied to galactooligosaccharides synthesis, evaluating the initial lactose concentration, pH and temperature, and yields of 30% were achieved. Moreover, excellent operational stability was obtained, since the immobilized enzyme maintained 100% of its initial activity after 25 batches of lactose hydrolysis. Thus, the food grade chitosan–genipin particles seem to be a good alternative for application in food process.
•Nanoparticles have the ideal characteristics for immobilizing enzymes.•Potential nanomaterials as supports will be presented.•Nanoscience highlighted as one of the most important research and ...development frontiers in modern science.•Nanoparticles offer many advantages due to size and physical properties.•Immobilization on nanoparticles shows important advantages.
Nanostructures are very attractive for enzymatic immobilization processes, since they possess ideal characteristics to equilibrate principal factors which determine biocatalysts efficiency, including specific surface area, mass transfer resistance and effective enzyme loading. A lot of materials are used at nano-size in processes of immobilization, like silica, chitosan, gold, diamond, metals, including graphene and zirconium. The functionalization of these supports is thoroughly studied. The focus of this review is to present the current status and some trends in enzymatic nanoimmobilization. Some applications of nanoimmobilized enzymes are explained in this review as well, considering biodiesel production, esters synthesis and biosensors.
The effect of the support size on the properties of enzyme immobilization was investigated by using chitosan macroparticles and nanoparticles. They were prepared by precipitation and ionotropic ...gelation, respectively, and were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), transmission electron microscopy (TEM), light scattering analysis (LSA), and N2 adsorption–desorption isotherms. β-Galactosidase was used as a model enzyme. It was found that the different sizes and porosities of the particles modify the enzymatic load, activity, and thermal stability of the immobilized biocatalysts. The highest activity was shown by the enzyme immobilized on nanoparticles when 204.2 mg protein·(g dry support)−1 were attached. On the other hand, the same biocatalysts presented lower thermal stability than macroparticles. β-Galactosidase immobilized on chitosan macro and nanoparticles exhibited excellent operational stability at 37 °C, because it was still able to hydrolyze 83.2 and 75.93% of lactose, respectively, after 50 cycles of reuse.
► High thermal stability in presence of concentrated lactose. ► GOS synthesized with high productivities. ► Effective lactose conversion in a 15 days steady-state operation.
β-d-Galactosidase from ...Kluyveromyces lactis was immobilized on glutaraldehyde-activated chitosan and used in a packed-bed reactor for the continuous hydrolysis of lactose and the synthesis of galactooligosaccharides (GOS). The biocatalyst was tested for its optima pH and temperature, thermal stability in the presence of substrate and products, and operational stability. Immobilization increased the range of operational pH and temperature, and the enzyme thermal stability was sharply increased in the presence of lactose. Almost complete lactose hydrolysis was achieved for both milk whey and lactose solution at 37°C at flow rates up to 2.6mLmin−1. Maximal GOS concentration of 26gL−1 was obtained at a flow rate of 3.1mLmin−1, with a productivity of 186gL−1h−1. Steady-state operation for 15 days showed the reactor stability concerning lactose hydrolysis.
Nanobiocatalysts were produced via immobilization of CalB lipase on polyurethane (PU) based nanoparticles and their application on the synthesis of important industrial products was evaluated. ...Nanoparticles of polyurethane functionalized with poly(ethylene glycol) (PU-PEG) were synthetized through miniemulsion polymerization and the addition of crosslinking agents were evaluated. The nanoparticles were employed as support for CalB and the kinetic parameters were reported. The performance of new biocatalysts was evaluated on the hydrolysis reaction of p-NPB and on the enantioselective hydrolysis of (R,S)-mandelic acid. The esterification reaction was evaluated on the production of ethyl esters of Omega-3. The effect of poly(ethylene glycol) molar mass (400, 4000 or 6000 Da)on the biocatalyst activity was also analyzed. The PU-PEG6000-CalB showed the highest value of the kinetic parameters, highlighting the high reaction rate. The addition of trehalose as crosslinking agent improved the thermal stability of the biocatalysts. PU-PEG400-CalB was the most active nanobiocatalyst, exhibiting a ethyl esters production of 43.72 and 16.83 mM.U -1 using EPA and DHA, respectively. The nanobiocatalyst was also applied in enantiomeric resolution of mandelic acid, showing promising enantiomeric ratios. The results obtained in this work present alternative and sustainable routes for the synthesis of important compounds used on food and pharmaceutical industries.
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•High recovered activity (100%) for CalB on PU-PEGylated particles.•The use of PEI and trehalose improved the thermal stability of the biocatalyst.•Kinect parameters show better performance for PU-PEG6000-CalB.•CalB-PU-PEG was used efficiently in synthesis of ethyl esters of Omega3 fatty acids.•For enantioselective reactions, an ee of 95 was obtained.
Duckweed has been proposed as a potential raw material to produce renewable biofuels, signified by: its high productivity and low competition with agriculture; its high proportion of carbohydrate ...(cellulose and starch); a low lignin content, which avoids the likely recalcitrance of cellulose to saccharification. This study has investigated the effect of hydrothermal pre-treatment on structural and chemical changes in Brazilian duckweed (L. punctata) biomass as well as its conversion to bioethanol, focusing on the hydrolysis and fermentation of the cellulose fraction. The biomass was hydrothermally pre-treated over a range of severities (1.9–4.8) and then subjected to simultaneous saccharification and fermentation. The best pre-treatment condition was at a severity factor of 3.9; this condition produced the highest ethanol yield (89 wt% of the theoretical potential yield). This represents a 63 wt% increase compared to untreated biomass. Hydrothermal pre-treatment has been shown to be a suitable technology for increasing ethanol yields from L. punctata biomass towards the theoretical maximum.
•Hydrothermal pre-treatments of Brazilian duckweed were investigated.•The pre-treatment facilitates the solubilisation of cellulose and starch.•Hydrothermal pre-treatment enhanced ethanol yield to 63% over untreated biomass.
Apple pomace is the processing waste generated after apple juice manufacturing and represents up to 30% of the original fruit. This solid residue consists of a complex mixture of peel, core, seed, ...calyx, stem, and soft tissue. This residual material is a poor animal feed supplement because of its extremely low protein content and high amount of sugar. The application of agroindustrial by-products in bioprocesses offers a wide range of alternative substrates, thus helping solve pollution problems related to their disposal. Attempts have been made to use apple pomace to generate several value-added products, such as enzymes, single cell protein, aroma compounds, ethanol, organic acids, polysaccharides, and mushrooms. This article reviews recent developments regarding processes and products that employed apple pomace as a substrate for biotechnological applications.
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•TLL lipase can be efficiently immobilized on PU-PEG particles.•PU-PEG particles coated increase the stability of the enzyme.•The coating with PEI improved the production of ethyl ...esters.•High productions of ethyl esters of Omega-3 fatty acids were obtained.
The adsorption of Thermomyces lanuginosus lipase (TLL) on PEGylated polyurethane particles as support permitted the development of several strategies to improve the properties of this commercial low-cost enzyme. The supports were synthesized by miniemulsion technique using isophoronediisocyanate (IPDI) and poly(ε-caprolactone) diol (PCL530) as monomers. The aqueous phase was composed of distilled water, surfactant sodium dodecyl sulfate (SDS), and poly(ethylene glycol) with different molar mass (PEG 400, 4000 or 6000). Polyethyleneimine (PEI) and trehalose were used to coat the PU-PEG polyurethane particles in order to increase the stability. In general, the coating with PEI (20%) allowed a greater stability of the derivatives. (100% of relative activity at 50°C during 8h). TLL immobilized on PEGylated polyurethane particles was efficiently used in the production of ethyl esters from fish oil compared to the free TLL (data not shown). The values of ethyl esters production of EPA and DHA were dependent on the support used for immobilization, which proved to be a determining factor in the activity. The highest selectivity obtained value was 45.8 for the PU-PEG4000-PEI20 derivative.
The named “green chemistry” has been receiving increasing prominence due to its environmentally friendly characteristics. The use of enzymes as catalysts in processes of synthesis to replace the ...traditional use of chemical catalysts present as main advantage the fact of following the principles of the green chemistry. However, processes of enzymatic nature generally provide lower yields when compared to the conventional chemical processes. Therefore, in the last years, the ultrasound has been extensively used in enzymatic processes, such as the production of esters with desirable characteristics for the pharmaceutical, cosmetics, and food industry, for the hydrolysis and glycerolysis of vegetable oils, production of biodiesel, etc. Several works found in the open literature suggest that the energy released by the ultrasound during the cavitation phenomena can be used to enhance mass transfer (substrate/enzyme), hence increasing the rate of products formation, and also contributing to enhance the enzyme catalytic activity. Furthermore, the ultrasound is considered a “green” technology due to its high efficiency, low instrumental requirement and significant reduction of the processing time in comparison to other techniques. The main goal of this review was to summarize studies available to date regarding the application of ultrasound in enzyme-catalyzed esterification, hydrolysis, glycerolysis and transesterification reactions.
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