Recent advances in β-galactosidase and fructosyltransferase immobilization technology

An activatable fluorescence probe for rapid detection and in situ imaging of β-galactosidase activity in cabbage roots under heavy metal stress

β-Galactosidase (β-gal), an enzyme related to cell wall degradation, plays an important role in regulating cell wall metabolism and reconstruction. However, activatable fluorescence probes for the detection and imaging of β-gal fluctuations in plants have been less exploited. Herein, we report an activatable fluorescent probe based on intramolecular charge transfer (ICT), benzothiazole coumarin-bearing β-galactoside (BC-βgal), to achieve distinct in situ imaging of β-gal in plant cells. It exhibits high sensitivity and selectivity to β-gal with a fast response (8 min). BC-βgal can be used to efficiently detect the alternations of intracellular β-gal levels in cabbage root cells with considerable imaging integrity and imaging contrast. Significantly, BC-βgal can assess β-gal activity in cabbage roots under heavy metal stress (Cd2+, Cu2+, and Pb2+), revealing that β-gal activity is negatively correlated with the severity of heavy metal stress. Our work thus facilitates the study of β-gal biological mechanisms.

Tailored chitosan integration in diatomaceous earth particles as a scaffold for fructosyltransferase immobilization in fructo-oligosaccharide production

BACKGROUND

Fructo-oligosaccharide (FOS) belongs to the group of short inulin-type fructans and is one of the most important non-digestible bifid-oligosaccharides capable of biotransforming sucrose using fructosyltransferase (FTase). However, there are no immobilized FTase products that can be successfully used industrially. In this study, diatomite was subjected to extrusion, sintering and granulation to form diatomaceous earth particles that were further modified via chitosan aminomethylation for modification. FTase derived from Aspergillus oryzae was successfully immobilized on the modified support via covalent binding.

RESULTS

The immobilized enzyme activity was 503 IU g-1 at an enzyme concentration of 0.6 mg mL-1, immobilization pH of 7.0 and contact time of 3 h. Additionally, the immobilization yield was 56.91%. Notably, the immobilized enzyme was more stable under acidic conditions. Moreover, the half-life of the immobilized enzyme was 20.80 and 10.96 times as long as that of the free enzyme at 45 and 60 °C, respectively. The results show good reusability, as evidenced by the 84.77% retention of original enzyme activity after eight cycles. Additionally, the column transit time of the substrate was 35.56 min when the immobilized enzyme was applied in a packed-bed reactor. Furthermore, a consistently high FOS production yield of 60.68% was achieved and maintained over the 15-day monitoring period.

CONCLUSIONS

Our results suggest that immobilized FTase is a viable candidate for continuous FOS production on an industrial scale. © 2024 Society of Chemical Industry.

Application of cold-adapted microbial agents in soil contaminate remediation: biodegradation mechanisms, case studies, and safety assessments

The microbial agent technology has made significant progress in remediating nitro-aromatic compounds (NACs), such as p-nitrophenol, 2,4-dinitrophenol, and 2,4,6-Trinitrotoluene, in farmland soil over the past decade. However, there are still gaps in our understanding of the bioavailability and degradation mechanisms of these compounds in low-temperature environments. In this review, we provide a comprehensive summary of the strategies employed by cold-adapted microorganisms and elucidate the degradation pathways of NACs pollutants. To further analyze their metabolic mechanisms, we propose using mass balance to improve our understanding of biochemical processes and refine the degradation pathways through stoichiometry analysis. Additionally, we suggest employing 13C-metabolic flux analysis to track enzyme activity and intermediate products during bio-degradation processes with the aim of accelerating the remediation of nitro-aromatic compounds, particularly in cold regions. Through a comprehensive analysis of pollutant metabolic activities and a commitment to the 'One Health' approach, with an emphasis on selecting non-pathogenic strains, the environmental management strategies for soil remediation could be positioned to develop and implement safe and effective measure.

β-Galactosidase: a traditional enzyme given multiple roles through protein engineering

β-Galactosidases are crucial carbohydrate-active enzymes that naturally catalyze the hydrolysis of galactoside bonds in oligo- and disaccharides. These enzymes are commonly used to degrade lactose and produce low-lactose and lactose-free dairy products that are beneficial for lactose-intolerant people. β-galactosidases exhibit transgalactosylation activity, and they have been employed in the synthesis of galactose-containing compounds such as galactooligosaccharides. However, most β-galactosidases have intrinsic limitations, such as low transglycosylation efficiency, significant product inhibition effects, weak thermal stability, and a narrow substrate spectrum, which greatly hinder their applications. Enzyme engineering offers a solution for optimizing their catalytic performance. The study of the enzyme's structure paves the way toward explaining catalytic mechanisms and increasing the efficiency of enzyme engineering. In this review, the structure features of β-galactosidases from different glycosyl hydrolase families and the catalytic mechanisms are summarized in detail to offer guidance for protein engineering. The properties and applications of β-galactosidases are discussed. Additionally, the latest progress in β-galactosidase engineering and the strategies employed are highlighted. Based on the combined analysis of structure information and catalytic mechanisms, the ultimate goal of this review is to furnish a thorough direction for β-galactosidases engineering and promote their application in the food and dairy industries.

Characterization of an isolated lactase enzyme produced by Bacillus licheniformis ALSZ2 as a potential pharmaceutical supplement for lactose intolerance

Introduction

Lactose intolerance is a widespread problem that affects people of many different races all over the world. The following pharmacological supplements can improve the lives of those who suffer from this issue.

Methods

This work focused on lactase producer isolation and statistical design (Plackett-Burman, and BOX-Behnken) to maximize the effectiveness of environmental factors. A lactase-producing bacterium was chosen from a discovery of 100 strains in soil that had previously been polluted with dairy products. Plackett-Burman investigated fifteen variables.

Results

The most critical variables that lead to increased lactase synthesis are glucose, peptone, and magnesium sulfate (MgSO4). The ideal process conditions for the creation of lactase yield among the stated variables were then determined using a BOX-Benken design. To establish a polynomial quadratic relationship between the three variables and lactase activity, the Box-Behnken design level was used. The EXCEL-solver nonlinear optimization technique was used to predict the best form for lactase production. The ideal temperature and pH levels have been determined, both before and after the lactase purification process, to achieve the highest performance of isolated lactase.

Conclusion

According to this study, Bacillus licheniformis is a perfect supply of the lactase enzyme (β -Galactosidase), It can be used as a product to assist people who have health issues due to lactose intolerance.

Advances in Low-Lactose/Lactose-Free Dairy Products and Their Production

With increasing health awareness worldwide, lactose intolerance has become a major concern of consumers, creating new market opportunities for low-lactose/lactose-free dairy foods. In recent years, through innovating processes and technologies, dairy manufacturers have significantly improved the variety, and functional and sensory qualities of low-lactose and lactose-free dairy products. Based on this, this paper first covers the pathology and epidemiology of lactose intolerance and market trends. Then, we focus on current advantages and disadvantages of different lactose hydrolysis technologies and improvements in these technologies to enhance nutritional value, and functional, sensory, and quality properties of lactose-free dairy products. We found that more and more cutting-edge technologies are being applied to the production of lactose-free dairy products, and that these technologies greatly improve the quality and production efficiency of lactose-free dairy products. Hopefully, our review can provide a theoretical basis for the marketing expansion and consumption guidance for low-lactose/lactose-free dairy products.

Application of Emerging Techniques in Reduction of the Sugar Content of Fruit Juice: Current Challenges and Future Perspectives

In light of the growing interest in products with reduced sugar content, there is a need to consider reducing the natural sugar concentration in juices while preserving the initial concentration of nutritional compounds. This paper reviewed the current state of knowledge related to mixing juices, membrane processes, and enzymatic processes in producing fruit juices with reduced concentrations of sugars. The limitations and challenges of these methods are also reviewed, including the losses of nutritional ingredients in membrane processes and the emergence of side products in enzymatic processes. As the existing methods have limitations, the review also identifies areas that require further improvements and technological innovations.

Co-Immobilization of Lactase and Glucose Isomerase on the Novel g-C3N4/CF Composite Carrier for Lactulose Production

The g-C₃N₄/CF composite carrier was prepared by ultrasound-assisted maceration and high-temperature calcination. The enzyme immobilization using the g-C₃N₄/CF as the novel carrier to immobilize lactase and glucose isomerase was enhanced for lactulose production. The carbon fiber (CF) was mixed with melamine powder in the mass ratio of 1:8. The g-C₃N₄/CF composite carrier was obtained by calcination at 550 °C for 3 h. After the analysis of characteristics, the g-C₃N₄/CF was successfully composited with the carbon nitride and CF, displaying the improvement of co-immobilization efficiency with the positive effects on the stability of the enzyme. The immobilization efficiency of the co-immobilized enzyme was 37% by the novel carrier of g-C₃N₄/CF, with the enzyme activity of 13.89 U g^-1 at 60 °C. The relative activities of co-immobilized enzymes maintained much more steadily at the wider pH and higher temperature than those of the free dual enzymes, respectively. In the multi-batches of lactulose production, the relative conversion rates in enzymes co-immobilized by the composite carrier were higher than that of the free enzymes during the first four batches, as well as maintaining about a 90% relative conversation rate after the sixth batch. This study provides a novel method for the application of g-C₃N₄/CF in the field of immobilizing enzymes for the production of lactulose.

Coimmobilized enzymes as versatile biocatalytic tools for biomass valorization and remediation of environmental contaminants - A review

Due to stringent regulatory norms, waste processing faces confrontations and challenges in adapting technology for effective management through a convenient and economical system. At the global level, attempts are underway to achieve a green and sustainable treatment for the valorization of lignocellulosic biomass as well as organic contaminants in wastewater. Enzymatic treatment in the environmental aspect thrived on being the promising rapid strategy that appeased the aforementioned predicament. On that account, coimmobilization of various enzymes on single support enhances the catalytic activity ensuing operational stability with industrial applications. This review pivoted towards the coimmobilization of enzymes on diverse supports and their applications in biomass conversion to industrial value-added products and removal of contaminants in wastewater. The limelight of this study chronicles the unique breakthroughs in biotechnology for the production of reusable biocatalysts, which inculcating various enzymes towards the scope of environment application.

Bioconversion of Lactose into Glucose–Galactose Syrup by Two-Stage Enzymatic Hydrolysis

Fermentation technology enables the better use of resources and the conversion of dairy waste into valuable food products. The aim of this study is to evaluate the conversion rate of glucose into fructose by immobilised glucose isomerase (GI) in sweet and acid whey permeates for glucose–galactose syrup production. The experiments demonstrated that the highest concentration of glucose and galacto-oligosaccharides (GOSs) in sweet and acid whey permeates was reached by GODO-YNL2 β-galactosidase, 32 ± 2% and 28 ± 1%, respectively. After glucose isomerisation, the highest fructose yield was 23 ± 0.3% and 13 ± 0.4% in sweet and acid whey permeates, where Ha-Lactase 5200 β-galactosidase was used for lactose hydrolysis in sweet and acid whey permeates. Finally, the results of this study highlight the potential for two-stage enzymatic hydrolysis to increase the sweetness of glucose–galactose syrup made from sweet and acid whey permeates.

Immobilization of β-Galactosidase by Encapsulation of Enzyme-Conjugated Polymer Nanoparticles Inside Hydrogel Microparticles

Increasing the shelf life of enzymes and making them reusable is a prominent topic in biotechnology. The encapsulation inside hydrogel microparticles (HMPs) can enhance the enzyme's stability by preserving its native conformation and facilitating continuous biocatalytic processes and enzyme recovery. In this study, we present a method to immobilize β-galactosidase by, first, conjugating the enzyme onto the surface of polymer nanoparticles, and then encapsulating these enzyme-conjugated nanoparticles (ENPs) inside HMPs using microfluidic device paired with UV-LEDs. Polymer nanoparticles act as anchors for enzyme molecules, potentially preventing their leaching through the hydrogel network especially during swelling. The affinity binding (through streptavidin-biotin interaction) was used as an immobilization technique of β-galactosidase on the surface of polymer nanoparticles. The hydrogel microparticles of roughly 400 μm in size (swollen state) containing unbound enzyme and ENPs were produced. The effects of encapsulation and storage in different conditions were evaluated. It was discovered that the encapsulation in acrylamide (AcAm) microparticles caused an almost complete loss of enzymatic activity. Encapsulation in poly(ethylene glycol) (PEG)-diacrylate microparticles, on the other hand, showed a residual activity of 15-25%, presumably due to a protective effect of PEG during polymerization. One of the major factors that affected the enzyme activity was presence of photoinitiator exposed to UV-irradiation. Storage studies were carried out at room temperature, in the fridge and in the freezer throughout 1, 7 and 28 days. The polymer nanoparticles showcased excellent immobilization properties and preserved the activity of the conjugated enzyme at room temperature (115% residual activity after 28 days), while a slight decrease was observed for the unbound enzyme (94% after 28 days). Similar trends were observed for encapsulated ENPs and unbound enzyme. Nevertheless, storage at -26°C resulted in an almost complete loss of enzymatic activity for all samples.

Immobilized phytases: an overview of different strategies, support material, and their applications in improving food and feed nutrition

Phytases are the most widely used food and feed enzymes, which aid in nutritional improvement by reducing anti-nutritional factor. Despite the benefits, enzymes usage in the industry is restricted by several factors such as their short life-span and poor reusability, which result in high costs for large-scale utilization at commercial scale. Furthermore, under pelleting conditions such as high temperatures, pH, and other factors, the enzyme becomes inactive due to lesser stability. Immobilization of phytases has been suggested as a way to overcome these limitations with improved performance. Matrices used to immobilize phytases include inorganic (Hydroxypatite, zeolite, and silica), organic (Polyacrylamide, epoxy resins, alginate, chitosan, and starch agar), soluble matrix (Polyvinyl alcohol), and nanomaterials including nanoparticles, nanofibers, nanotubes. Several surface analysis methods, including thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and FTIR analysis, have been used to characterize immobilized phytase. Immobilized phytases have been used in a broad range of biotechnological applications such as animal feed, biodegradation of food phytates, preparations of myo-inositol phosphates, and sulfoxidation by vanadate-substituted peroxidase. This article provides information on different matrices used for phytase immobilization from the last two decades, including the process of immobilization and support material, surface analysis techniques, and multifarious biotechnological applications of the immobilized phytases.

Potential and Scale-Up of Pore-Through-Flow Membrane Reactors for the Production of Prebiotic Galacto-Oligosaccharides with Immobilized β-Galactosidase

The production of prebiotics like galacto-oligosaccharides (GOS) on industrial scale is becoming more important due to increased demand. GOS are synthesized in batch reactors from bovine lactose using the cost intensive enzyme β-galactosidase (β-gal). Thus, the development of sustainable and more efficient production strategies, like enzyme immobilization in membrane reactors are a promising option. Activated methacrylatic monoliths were characterized as support for covalent immobilized β-gal to produce GOS. The macroporous monoliths act as immobilized pore-through-flow membrane reactors (PTFR) and reduce the influence of mass-transfer limitations by a dominating convective pore flow. Monolithic designs in the form of disks (0.34 mL) and for scale-up cylindric columns (1, 8 and 80 mL) in three different reactor operation configurations (semi-continuous, continuous and continuous with recirculation) were studied experimentally and compared to the free enzyme system. Kinetic data, immobilization efficiency, space-time-yield and long-term stability were determined for the immobilized enzyme. Furthermore, simulation studies were conducted to identify optimal operation conditions for further scale-up. Thus, the GOS yield could be increased by up to 60% in the immobilized PTFRs in semi-continuous operation compared to the free enzyme system. The enzyme activity and long-time stability was studied for more than nine months of intensive use.

In situ purification and enrichment of fructo-oligosaccharides by fermentative treatment with Bacillus coagulans and selective catalysis using immobilized fructosyltransferase

Fructo-oligosaccharides (FOS) are prebiotic sugar substitutes that can be produced from sucrose using fructosyltransferases (FTases). However, the economic value of this process is limited by inefficient product purification and enzyme reusability. In this study, enzyme-free FOS preparations were produced by immobilizing the FTase on resin carriers. This also increased the catalytic selectivity of the enzyme. However, the crude FOS preparations still contained high concentrations of monosaccharide byproducts and residual disaccharides that must be removed because they lack prebiotic activity. A hybrid process was developed in which fed-batch fermentation was combined with the probiotic bacterium Bacillus coagulans (which selectively utilizes monosaccharides) and the simultaneous conversion of residual sucrose using the FTase to increase FOS purity. This process depleted the monosaccharides and increased the concentration of FOS to 130-170 g·L^-1. The residual sucrose was converted to FOS by the immobilized FTase, increasing the overall purity of FOS to 92.1%.

Development of a Hybrid Bioinorganic Nanobiocatalyst: Remarkable Impact of the Immobilization Conditions on Activity and Stability of β-Galactosidase

Hybrid bioinorganic biocatalysts have received much attention due to their simple synthesis, high efficiency, and structural features that favor enzyme activity and stability. The present work introduces a biomineralization strategy for the formation of hybrid nanocrystals from β-galactosidase. The effects of the immobilization conditions were studied, identifying the important effect of metal ions and pH on the immobilization yield and the recovered activity. For a deeper understanding of the biomineralization process, an in silico study was carried out to identify the ion binding sites at the different conditions. The selected β-galactosidase nanocrystals showed high specific activity (35,000 IU/g biocatalyst) and remarkable thermal stability with a half-life 11 times higher than the soluble enzyme. The nanobiocatalyst was successfully tested for the synthesis of galacto-oligosaccharides, achieving an outstanding performance, showing no signs of diffusional limitations. Thus, a new, simple, biocompatible and inexpensive nanobiocatalyst was produced with high enzyme recovery (82%), exhibiting high specific activity and high stability, with promising industrial applications.

Purified lactases versus whole-cell lactases-the winner takes it all

Lactose-free dairy products are in great demand worldwide due to the high prevalence of lactose intolerance. To make lactose-free dairy products, commercially available β-galactosidase enzymes, also termed lactases, are used to break down lactose to its constituent monosaccharides, glucose and galactose. In this mini-review, the characteristics of lactase enzymes, their origin, and ways of use are discussed in light of their potential for hydrolyzing lactose. We also discuss whole-cell lactase catalysts, which appear to have great potential in terms of cost reduction and convenience, and which are more natural alternatives to purified enzymes. Lactic acid bacteria (LAB) already used in food fermentations seem to be optimal candidates for whole-cell lactases. However, they have not been industrially exploited yet due to technical hurdles. For whole-cell lactases to be efficient, the lactase enzymes inside the cells must be made available for lactose hydrolysis, and thus, cells need to be permeabilized or disrupted prior to use. Here we review state-of-the-art approaches for disrupting or permeabilizing microorganisms. Lastly, based on recent scientific achievements, we propose a novel, resource-efficient, and low-cost scenario for achieving lactose hydrolysis at a dairy plant using a LAB whole-cell lactase.Key points• Lactases (β-galactosidase) are essential for producing lactose-free dairy products• Novel permeabilization techniques facilitate the use of LAB lactases• Whole-cell lactase catalysts have great potential for reducing costs and resources Graphical abstract.

Immobilization of β-galactosidase by halloysite-adsorption and entrapment in a cellulose nanocrystals matrix

BACKGROUND

Immobilization allows easy recovery and reuse of enzymes in industrial processes. In addition, it may enhance enzyme stability, allowing prolonged use. A simple and novel method of immobilizing β-galactosidase is reported. Effects of immobilization on the enzyme characteristics are explained. β-Galactosidase is well established in dairy processing and has emerging applications in novel syntheses.

METHODS

β-Galactosidase was immobilized by physical adsorption on halloysite, an aluminosilicate nanomaterial. Optimal conditions for adsorption were identified. The optimally prepared halloysite-adsorbed enzyme was then entrapped in a porous matrix of nanocrystals of sulfated bacterial cellulose, to further enhance stability.

RESULTS

Under optimal conditions, 89.5% of the available protein was adsorbed per mg of halloysite. The most active and stable final immobilized biocatalyst had 1 part by mass of the enzyme-supporting halloysite particles mixed with 2 parts of cellulose nanocrystals. Immobilization raised the optimal pH of the catalyst to 7.5 (from 6.0 for the native enzyme) and temperature to 55 °C (40 °C for the native enzyme). During storage at 25 °C, the immobilized enzyme retained 75.8% of initial activity after 60 days compared to 29.2% retained by the free enzyme.

CONCLUSION

The immobilization method developed in this work enhanced enzyme stability during catalysis and storage. Up to 12 cycles of repeated use of the catalyst became feasible.

GENERAL SIGNIFICANCE

The simple and rapid immobilization strategy of this work is broadly applicable to enzymes used in diverse bioconversions.

Magnetic graphene oxide nanocomposites as an effective support for lactase immobilization with improved stability and enhanced photothermal enzymatic activity

Magnetic graphene oxide-immobilized lactase with high loading capacity, improved stabilities, and photothermal enhancement of activity has been reported.