Manures may contain considerable amounts of organophosphates (org-P) that must be enzymatically converted to inorganic phosphate (i.e., PO4-P) to be plant available. Although adding enzymes into ...manures can facilitate mineralization of org-P to PO4-P, enzymes that are not immobilized are easily lost through leaching, degradation, or denaturation. In this study, the immobilization of enzymes onto nine different biochar surfaces was explored. Phytase, which mineralizes a main class of org-P, was used as the model enzyme. Immobilization methods included covalent grafting accomplished by the carbodiimide crosslinker method and physical sorption. The results showed that physisorption was as effective as grafting for loading phytase to the biochars. Phytase loading after mixing 0.1 g biochar and 2 mg phytase correlated positively with biochar C:H ratio (an indicator of aromatic content) suggesting the importance of the hydrophobic effect. An increase in pH led to a decrease in phytase loading consistent with repulsion between negatively charged sites on phytase and the increasing negative charge on biochar. Less than 4% of the immobilized phytase leached after sequential extractions over seven days using manure dissolve organic matter solutions. However, the activity of immobilized phytase decreased markedly compared to the free state phytase. The specific activity of immobilized phytase was two orders of magnitude lower than that of free phytase at pH 5 and 7. Nevertheless, results showed that deactivation of phytase by biochars were reversible once the phytase was detached from the surfaces. Compared to the biochars, clay minerals (montmorillonite, kaolinite and hematite) tended to have greater loading rates and higher phytase activity. Composting manures with coamendments of biochar and minerals may enhance both short- and long-term P mineralization potential.
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•Phytase is effectively bound by physisorption with no need for covalent grafting.•Phytase loading rate is largely influenced by pH and biochar aromatic content.•Phytase binding was irreversible even in high concentrations of manure extract.•Binding to biochars reduces phytase activity more so than clay mineral tested.
The Cover Feature shows the carrier‐free immobilization of self‐assembled multi‐enzyme complexes formed on the basis of polypeptide interactions and enzyme oligomerization. Such supermolecular and ...water‐insoluble enzyme complexes feature a high reaction rate and good recycling capability for the biological multi‐enzyme biocatalytic conversion of starch into inositol. The proposed strategy for the carrier‐free immobilization of the enzyme complex sheds light on improving the catalytic efficiency of in vitro synthetic enzymatic biosystems. More information can be found in the Research Article by M. Liu et al.
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•The demand for environmentally-friendly catalysts blooms hugely these years.•The scope of hybrid nanoflowers is narrowed, the synthesis procedures and species of EHNFs are introduced ...specifically.•The mechanisms and influencing factors of activity improvements for employed enzymes are interpreted.•The recent representative multi-functional applications for EHNFs, not confined to biocatalysis, are demonstrated.
Enzyme-based hybrid nanoflowers (EHNFs) provide a way to immobilize the enzymes without harsh conditions and mass transfer limitations, as well as promote the performances of the enzymes. This kind of immobilization attracted a considerable interest in further developing the application of enzymatic reactions. Therefore, the comprehensive understanding of the preparation, micro-structure, and catalytic behavior of EHNFs is critical for their better application. In this review, a wide variety of EHNFs in terms of synthesis, categories, morphologies and their applications in biocatalytic, biomedical, environment and bioenergy are introduced. Additionally, we discuss the future trends and perspectives of EHNFs in order to offer rational suggestions for the future researches and developments of these promising biocatalysts.
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•Organic nanosupports are highly biocompatible.•Organic nanosupports mainly increase Km an Vmax of immobilized enzymes.•Organic nanosupports mainly increase ΔH and ΔS values of ...immobilized enzymes.•Organic nanosupports mainly decrese ΔG value of immobilized enzymes.•Organic hybrid nano-support materials will be used extensively for enzyme immobilization.
A variety of organic nanomaterials and organic polymers are used for enzyme immobilization to increase enzymes stability and reusability. In this study, the effects of the immobilization of enzymes on organic and organic-inorganic hybrid nano-supports are compared. Immobilization of enzymes on organic support nanomaterials was reported to significantly improve thermal, pH and storage stability, acting also as a protection against metal ions inhibitory effects. In particular, the effects of enzyme immobilization on reusability, physical, kinetic and thermodynamic parameters were considered. Due to their biocompatibility with low health risks, organic support nanomaterials represent a good choice for the immobilization of enzymes. Organic nanomaterials, and especially organic-inorganic hybrids, can significantly improve the kinetic and thermodynamic parameters of immobilized enzymes compared to macroscopic supports. Moreover, organic nanomaterials are more environment friendly for medical applications, such as prodrug carriers and biosensors. Overall, organic hybrid nanomaterials are receiving increasing attention as novel nano-supports for enzyme immobilization and will be used extensively.
Cell‐free enzymatic catalysis (CFEC) is an emerging biotechnology that enable the biological transformations in complex natural networks to be imitated. This biomimetic approach allows industrial ...products such as biofuels and biochemical to be manufactured in a green manner. Nevertheless, the main challenge in CFEC is the poor stability, which restricts the effectiveness and lifetime of enzymes in sophisticated applications. Immobilization of the enzymes within solid carriers is considered an efficient strategy for addressing these obstacles. Specifically, putting an “armor‐like” porous metal–organic framework (MOF) exoskeleton tightly around the enzymes not only shields the enzymes against external stimulus, but also allows the selective transport of guests through the accessible porous network. Herein we present the concept of this biotechnology of MOF‐entrapped enzymes and its cutting‐edge applications.
Armorous advances: Embedding enzymes within metal–organic framework (MOF) exoskeletons improves the stability and life‐time of enzymes. This Minireview shows the progress made with MOFs‐embedded enzymes. It focuses on new embedding strategies for constructing enzyme@MOF biocomposites and the factors that influence the change in enzymatic activity. In addition, applications of enzyme@MOFs in fields such as biocatalysis, sensing, and nanocatalysis therapeutics, are presented.
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•Understanding of the enzyme immobilization is required to optimize the processes.•Immobilization parameters and courses become critical to understand the process.•Changes in enzyme ...properties during immobilization can complicate the calculations.•Likely artifacts and problems to make these calculations are discussed.•Some advices to improve the understanding of immobilization processes are given.
Biocatalytic processes continue to find increasing application in industry. Therefore enzyme immobilization has also become of increasing importance as a means of allowing enzyme containment within reactors operating in continuous mode or else separation of enzyme after use in (fed-)batch reactors, as well as potential recycle. Whilst much has been reported in the scientific literature about enzyme immobilization methods, in many cases the protocol leads to losses in enzyme activity. In this review we outline the reasons for loss of activity during immobilization and highlight suitable diagnostic tests to elucidate the precise cause and thereby methods to restore activity. The need for standardized reporting of immobilization methods is also emphasized as a means of benchmarking alternative approaches.
Immobilized enzymes have received incredible interests in industry, pharmaceuticals, chemistry and biochemistry sectors due to their various advantages such as ease of separation, multiple ...reusability, non-toxicity, biocompatibility, high activity and resistant to environmental changes. This review in between various immobilized enzymes focuses on lipase as one of the most practical enzyme and chitosan as a preferred biosupport for lipase immobilization and provides a broad range of studies of recent decade. We highlight several aspects of lipase immobilization on the surface of chitosan support containing various types of lipase and immobilization techniques from physical adsorption to covalent bonding and cross-linking with their benefits and drawbacks. The recent advances and future perspectives that can improve the present problems with lipase and chitosan such as high-price of lipase and low mechanical resistance of chitosan are also discussed. According to the literature, optimization of immobilization methods, combination of these methods with other techniques, physical and chemical modifications of chitosan, co-immobilization and protein engineering can be useful as a solution to overcome the mentioned limitations.
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•Electrospun Fe(III)-PU/AOPAN/β-CD blend nanofiber membrane was prepared.•The membrane was studied as innovative carrier/support for immobilization of laccase.•The membrane’s ...immobilization amount of laccase reached a high value of 186.34mg/g.•The immobilized laccase showed high catalytic activity and temperature/pH resistance.•Thermal/storage stability and reusability of the immobilized laccase were improved.
The aim of this study is to develop high-performance carrier/support for immobilization of enzyme (e.g., laccase). The hypothesis is that electrospun blend nanofiber membrane consisting of polyurethane (PU), amidoxime polyarcylonitrile (AOPAN), and β-cyclodextrin (β-CD) would possess the desired morphological, mechanical, and chemical properties for the coordination/chelation of Fe(III) ions and the subsequent immobilization of laccase molecules. To test this hypothesis, the Fe(III)-PU/AOPAN/β-CD nanofiber membrane has been prepared and characterized first; thereafter, the membrane’s performance as laccase immobilization carrier/support has been investigated. The results indicate that the prepared nanofiber membrane can efficiently immobilize laccase, and it also possesses excellent morphological/mechanical properties and regeneration capability. In specific, the membrane’s immobilization amount of laccase reaches a high value of 186.34mg/g; moreover, the immobilized laccase exhibits reasonably high catalytic activity and significantly improved resistance against the variations of temperature and pH value than the free laccase. Additionally, thermal stability, storage stability, and reusability of the immobilized laccase are substantially improved; and the membrane carrier/support can also be regenerated/reused for several times. Therefore, the developed electrospun PU/AOPAN/β-CD blend nanofiber membrane is a high-performance carrier/support for efficient and reusable immobilization of laccase.
In recent years, lignocellulosic wastes have gathered much attention due to increasing economic, social, environmental apprehensions, global climate change and depleted fossil fuel reserves. The ...unsuitable management of lignocellulosic materials and related organic wastes poses serious environmental burden and causes pollution. On the other hand, lignocellulosic wastes hold significant economic potential and can be employed as promising catalytic supports because of impressing traits such as surface area, porous structure, and occurrence of many chemical moieties (i.e., carboxyl, amino, thiol, hydroxyl, and phosphate groups). In the current literature, scarce information is available on this important and highly valuable aspect of lignocellulosic wastes as smart carriers for immobilization. Thus, to fulfill this literature gap, herein, an effort has been made to signify the value generation aspects of lignocellulosic wastes. Literature assessment spotlighted that all these waste materials display high potential for immobilizing enzyme because of their low cost, bio-renewable, and sustainable nature. Enzyme immobilization has gained recognition as a highly useful technology to improve enzyme properties such as catalytic stability, performance, and repeatability. The application of carrier-supported biocatalysts has been a theme of considerable research, for the past three decades, in the bio-catalysis field. Nonetheless, the type of support matrix plays a key role in the immobilization process due to its influential impact on the physicochemical characteristics of the as-synthesized biocatalytic system. In the past, an array of various organic, inorganic, and composite materials has been used as carriers to formulate efficient and stable biocatalysts. This review is envisioned to provide recent progress and development on the use of different agricultural wastes (such as coconut fiber, sugarcane bagasse, corn and rice wastes, and Brewers' spent grain) as support materials for enzyme immobilization. In summary, the effective utilization of lignocellulosic wastes to develop multi-functional biocatalysts is not only economical but also reduce environmental problems of unsuitable management of organic wastes and drive up the application of biocatalytic technology in the industry.
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•Increasing socio-economic, and environmental apprehensions stresses on valorizing lignocellulosic wastes.•Various lignocellulosic wastes as promising immobilization supports are discussed.•Research gaps – beyond our notice are discussed from the future considerations' viewpoint.
•Enzymatic endowments of immobilized carbonic anhydrase.•Current approaches and supports of carbonic anhydrase immobilization.•Studies of CO2 capture technologies ameliorated by immobilized carbonic ...anhydrase.•Advantages, issues, and limitations of enzymatic CO2 capture processes.•Industrial implementation of enzymatic CO2 capture.
Currently, amine-based solutions are considered as benchmark absorbents for CO2 capture. However, there are severe environmental concerns as well as high energy consumption. A viable option is CO2 capture utilising water as absorbent, via a biomimetic approach by the enzyme carbonic anhydrase (CA), with high selectivity, upmost performance, and environmental friendliness. However, the employment of the free form of CA in industrial applications is not rational due to the considerable amounts of enzyme required, instability and non-reusability. The immobilization of CA has attained significant interest, appearing as a promising approach to solve the problems associated with free CA. In this context, different immobilization strategies and supports have been developed to ameliorate the activity, stability, and reusability of CA enzyme, lowering the cost and increasing the process efficiency in large-scale applications. CO2 capture has been studied using immobilized CA in various technologies such as absorption columns, selective membranes, and membrane contactors. In this state-of-the-art review, the scientific literature regarding the immobilization of CA and carbon capture technologies using immobilized CA are analyzed, highlighting the benefits, issues, and limitations of processes. Moreover, modelling approaches describing the absorption of CO2 in packed-bed and membrane bioreactors with immobilized CA are presented, as well as the impact of operating parameters on bioreactors performance. The techno-economic analyses carried out on enzymatic capture processes are reviewed as well, to assess their feasibility in an industrial context. Finally, concluding remarks are made with a recommended perspective on open challenges and research priorities.
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