Mesocellular Silica Foam as Immobilization Carrier for Production of Statin Precursors.

The employment of 2-deoxyribose-5-phosphate aldolase (DERA) stands as a prevalent biocatalytic route for synthesizing statin side chains. The main problem with this pathway is the low stability of the enzyme. In this study, mesocellular silica foam (MCF) with different pore sizes was used as a carrier for the covalent immobilization of DERA. Different functionalizing and activating agents were tested and kinetic modeling was subsequently performed. The use of succinic anhydride as an activating agent resulted in an enzyme hyperactivation of approx. 140%, and the stability almost doubled compared to that of the free enzyme. It was also shown that the pore size of MCF has a decisive influence on the stability of the DERA enzyme.

Mango Peels as an Industrial By-Product: A Sustainable Source of Compounds with Antioxidant, Enzymatic, and Antimicrobial Activity.

Plant waste materials are important sources of bioactive compounds with remarkable health-promoting benefits. In particular, industrial by-products such as mango peels are sustainable sources of bioactive substances, with antioxidant, enzymatic, and antimicrobial activity. Appropriate processing is essential to obtain highly bioactive compounds for further use in generating value-added products for the food industry. The objective of the study was to investigate and compare the biological activity of compounds from fresh and dried mango peels obtained by different conventional methods and unconventional extraction methods using supercritical fluids (SFE). The highest total phenolic content (25.0 mg GAE/g DW) and the total content of eight phenolic compounds (829.92 µg/g DW) determined by LC-MS/MS were detected in dried mango peel extract obtained by the Soxhlet process (SE). SFE gave the highest content of proanthocyanidins (0.4 mg PAC/g DW). The ethanolic ultrasonic process (UAE) provided the highest antioxidant activity of the product (82.4%) using DPPH radical scavenging activity and total protein content (2.95 mg protein/g DW). Overall, the dried mango peels were richer in bioactive compounds (caffeic acid, chlorogenic acid, gallic acid, catechin, and hesperidin/neohesperidin), indicating successful preservation during air drying. Furthermore, outstanding polyphenol oxidase, superoxide dismutase (SOD), and lipase activities were detected in mango peel extracts. This is the first study in which remarkable antibacterial activities against the growth of Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) were evaluated by determining the microbial growth inhibition rate after 12 and 24 h incubation periods for mango peel extracts obtained by different methods. Ethanolic SE and UAE extracts from dried mango peels resulted in the lowest minimum inhibitory concentrations (MIC90) for all bacterial species tested. Mango peels are remarkable waste products that could contribute to the sustainable development of exceptional products with high-added value for various applications, especially as dietary supplements.

Enzymatic, Antioxidant, and Antimicrobial Activities of Bioactive Compounds from Avocado (Persea americana L.) Seeds.

The aim of this research was to identify and quantify biologically active compounds from avocado (Persea americana L.) seeds (AS) utilizing different techniques with the use of ultrasound (US), ethanol (EtOH), and supercritical carbon dioxide (scCO2) for possible applications in (bio)medicine, pharmaceutical, cosmetic, or other relevant industries. Initially, a study of the process efficiency (η) was carried out, which revealed yields in the range of 2.96-12.11 wt%. The sample obtained using scCO2 was found to be the richest in total phenols (TPC) and total proteins (PC), while the sample obtained with the use of EtOH resulted in the highest content of proanthocyanidins (PAC). Phytochemical screening of AS samples, quantified by the HPLC method, indicated the presence of 14 specific phenolic compounds. In addition, the activity of the selected enzymes (cellulase, lipase, peroxidase, polyphenol oxidase, protease, transglutaminase, and superoxide dismutase) was quantified for the first time in the samples from AS. Using DPPH radical scavenging activity, the highest antioxidant potential (67.49%) was detected in the sample obtained with EtOH. The antimicrobial activity was studied using disc diffusion method against 15 microorganisms. Additionally, for the first time, the antimicrobial effectiveness of AS extract was quantified by determination of microbial growth-inhibition rates (MGIRs) at different concentrations of AS extract against three strains of Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and Pseudomonas fluorescens) bacteria, three strains of Gram-positive (Bacillus cereus, Staphylococcus aureus, and Streptococcus pyogenes) bacteria, and fungi (Candida albicans). MGIRs and minimal inhibitory concentration (MIC90) values were determined after 8 and 24 h of incubation, thus enabling the screening of antimicrobial efficacy for possible further applications of AS extracts as antimicrobial agents in (bio)medicine, pharmaceutical, cosmetic, or other industries. For example, the lowest MIC90 value was determined for B. cereus after 8 h of incubation in the case of UE and SFE extracts (70 µg/mL), indicating an outstanding result and the potential of AS extracts, as the MIC values for B. cereus have not been investigated so far.

Sustainable Biodegradable Biopolymer-Based Nanoparticles for Healthcare Applications.

Biopolymeric nanoparticles are gaining importance as nanocarriers for various biomedical applications, enabling long-term and controlled release at the target site. Since they are promising delivery systems for various therapeutic agents and offer advantageous properties such as biodegradability, biocompatibility, non-toxicity, and stability compared to various toxic metal nanoparticles, we decided to provide an overview on this topic. Therefore, the review focuses on the use of biopolymeric nanoparticles of animal, plant, algal, fungal, and bacterial origin as a sustainable material for potential use as drug delivery systems. A particular focus is on the encapsulation of many different therapeutic agents categorized as bioactive compounds, drugs, antibiotics, and other antimicrobial agents, extracts, and essential oils into protein- and polysaccharide-based nanocarriers. These show promising benefits for human health, especially for successful antimicrobial and anticancer activity. The review article, divided into protein-based and polysaccharide-based biopolymeric nanoparticles and further according to the origin of the biopolymer, enables the reader to select the appropriate biopolymeric nanoparticles more easily for the incorporation of the desired component. The latest research results from the last five years in the field of the successful production of biopolymeric nanoparticles loaded with various therapeutic agents for healthcare applications are included in this review.

Synergistic Effect of Supercritical and Ultrasound-Assisted Ginger (Zingiber officinale Roscoe) Extracts.

Proper processing of natural material is crucial to obtain an extract with high content of biologically active components. Dried, grinded ginger roots were extracted by ultrasonic method and supercritical extraction with CO2. The aim of the study was to determine if a mixture of the two types of extracts attained by different methods and solvents exhibits better bioavailability than each extract itself. Therefore, both extracts were analytically evaluated and then mixed in a ratio of 1:1. The supercritical extract (SCG extract) and the mixed extract (mixG extract) had high antioxidant activity (78% and 73%) and total phenols (827 mg/g ext. and 1455 mg/g ext.), which is also consistent with the levels of gingerol (303 mg/g ext. and 271 g/g ext.) and shogaol (111 mg/g ext. and 100 g/g ext.) in the extracts. In comparison to both pure extracts higher levels of total phenols were found in the extract mixG. This could be the reason for the significant inhibition of melanoma cells and antimicrobial potential (against Staphylococcus aureus, Escherichia coli, and Candida albicans). The combination of the extracts resulted in a significant increase in the inhibition of selected microbial and melanoma cells WM-266-4 compared to the control. Cell viability decreased below 60% when mixG extract was applied. Antimicrobial activity has been confirmed.

Supercritical Fluid and Conventional Extractions of High Value-Added Compounds from Pomegranate Peels Waste: Production, Quantification and Antimicrobial Activity of Bioactive Constituents.

This study is focused on different extractions (Cold Maceration (CM), Ultrasonic Extraction (UE), Soxhlet Extraction (SE) and Supercritical Fluid Extraction (SFE)) of bioactive compounds from pomegranate (Punica Granatum L.) fruit peels using methanol, ethanol, and acetone as solvents in conventional extractions and changing operating pressure (10, 15, 20, 25 MPa) in SFE, respectively. The extraction yields, total phenols (TP) and proanthocyanidins (PAC) contents, and antioxidant activity of different extracts are revealed. TP and PAC recovered by extracts ranged from 24.22 to 42.92 mg gallic acid equivalents (GAE)/g and 2.01 to 5.82 mg PAC/g, respectively. The antioxidant activity of extracts ranged from 84.70% to 94.35%. The phenolic compound identification and quantification in selective extracts was done using the LC-MS/MS method. The contents of different flavonoids and phenolic acids have been determined. SFE extract, obtained at 20 MPa, contained the highest content (11,561.84 µg/g) of analyzed total polyphenols, with predominant ellagic acid (7492.53 µg/g). For the first time, Microbial Growth Inhibition Rates (MGIRs) were determined at five different concentrations of pomegranate SFE extract against seven microorganisms. Minimal Inhibitory Concentration (MIC90) was determined as 2.7 mg/mL of SFE pomegranate peel extract in the case of five different Gram-negative and Gram-positive bacteria.

Exosomes Engineering and Their Roles as Therapy Delivery Tools, Therapeutic Targets, and Biomarkers.

Exosomes are becoming increasingly important therapeutic biomaterials for use in a variety of therapeutic applications due to their unique characteristics, especially due to the ineffectiveness and cytotoxicity of some existing therapies and synthetic therapeutic nanocarriers. They are highly promising as carriers of drugs, genes, and other therapeutic agents that can be incorporated into their interior or onto their surface through various modification techniques to improve their targeting abilities. In addition, they are biocompatible, safe, and stable. The review focuses on different types of exosomes and methods of their preparation, including the incorporation of different kinds of cargo, especially for drug delivery purposes. In particular, their importance and effectiveness as delivery vehicles of various therapeutic agents for a variety of therapeutic applications, including different diseases and disorders such as cancer treatment, cardiovascular and neurodegenerative diseases, are emphasized. Administration routes of exosomes into the body are also included. A novelty in the article is the emphasis on global companies that are already successfully developing and testing such therapeutic biomaterials, with a focus on the most influential ones. Moreover, a comparison of the advantages and disadvantages of the various methods of exosome production is summarized for the first time.

A Comprehensive Study of the Antibacterial Activity of Bioactive Juice and Extracts from Pomegranate (Punica granatum L.) Peels and Seeds.

Due to the growing awareness of Punica granatum fruit's health-promoting properties, the pomegranate is increasingly used for food purposes. This results in the formation of biological waste products such as peels. A biowaste circular bioeconomy strategy holds great prospective for a sustainable economy. Therefore, a sustainable and environmentally friendly way of disposing of waste (e.g., use of biowaste to obtain high-value components (e.g., punicalagins, enzymes)) is crucial for the protection of the environment and human health. In the presented study, the content of total phenols and proanthocyanidins in ten samples of Punica granatum fruit (juice, aqueous (H2O) and ethanolic (EtOH) extracts of peels and seeds) was determined. Peel extracts were found to be the richest in the content of secondary metabolites and showed extremely high antioxidant potential (approximately 90% inhibition: DPPH radical scavenging activity). To the best of our knowledge, this is the first comparative study to determine the enzymatic activity of α-amylase, lipase, peroxidase, protease, and transglutaminase in different P. granatum samples. Furthermore, the antibacterial efficacy of all P. granatum samples was qualitatively determined against three strains of Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and Pseudomonas fluorescens) and three strains of Gram-positive (Bacillus cereus, Staphylococcus aureus, and Streptococcus pyogenes) bacteria, susceptible to gaining antibiotic resistance. Moreover, the most promising peel extracts were quantified for antibacterial efficacy against tested bacteria at five different concentrations. All samples slowed down and inhibited the growth of all tested bacteria. MIC90 values (2.7 or 0.3 mg/mL) were determined in 18 out of 24 experiments (four samples, six bacteria tested). There is no research in the reviewed literature that is current with such detailed and comprehensive determination of P. granatum peel extracts antibacterial activity. The results of the research showed great potential for the use of P. granatum in the field of antibacterial activity in biomedicine applications and in the cosmetic, food, and pharmaceutical industries.

Enzymatic and Antimicrobial Activity of Biologically Active Samples from Aloe arborescens and Aloe barbadensis.

Recently, the use of Aloe species has become very widespread. These are extensively used as a nutraceutical in a variety of health care products and food supplements. In addition, the occurrence of the quickly adaptable microorganisms, particularly bacteria, which can develop resistance to antibiotics, is a major problem for public health, and therefore, it is necessary to search for new antimicrobials. In our study, the content of total phenols, proanthocyanidins, and proteins in fresh and lyophilized samples of A. arborescens and A. barbadensis and their ethanol extracts was investigated. Furthermore, enzymatic and antioxidant activity of samples were studied. Since antimicrobial activity of fresh samples was determined in our latest research, a more detailed study of antimicrobial effectiveness of A. arborescens and A. barbadensis (lyophilized, extracts) was performed. Ethanol extracts in particular contain higher concentrations of bioactive substances and show the topmost antioxidant activity. The novelty of the study refers to the observation of industrially important enzyme activities such as α-amylase, cellulase, lipase, peroxidase, protease, and transglutaminase in the samples as well as the microbial growth inhibition rates determination (MGIR) at different concentrations of added aloe samples. All samples inhibited the growth of all tested microbial cells. MIC90 for A. arborescens and A. barbadensis were also determined in case of B. cereus, P. aeruginosa, P. fluorescens, and S. aureus. The results of our study tend to give credence to the popular use of both aloes in medicine and in the cosmetic, food, and pharmaceutical industries.

(Bio)nanotechnology in Food Science-Food Packaging.

Background: Bionanotechnology, as a tool for incorporation of biological molecules into nanoartifacts, is gaining more and more importance in the field of food packaging. It offers an advanced expectation of food packaging that can ensure longer shelf life of products and safer packaging with improved food quality and traceability. Scope and approach: This review recent focuses on advances in food nanopackaging, including bio-based, improved, active, and smart packaging. Special emphasis is placed on bio-based packaging, including biodegradable packaging and biocompatible packaging, which presents an alternative to most commonly used non-degradable polymer materials. Safety and environmental concerns of (bio)nanotechnology implementation in food packaging were also discussed including new EU directives. Conclusions: The use of nanoparticles and nanocomposites in food packaging increases the mechanical strength and properties of the water and oxygen barrier of packaging and may provide other benefits such as antimicrobial activity and light-blocking properties. Concerns about the migration of nanoparticles from packaging to food have been expressed, but migration tests and risk assessment are unclear. Presumed toxicity, lack of additional data from clinical trials and risk assessment studies limit the use of nanomaterials in the food packaging sector. Therefore, an assessment of benefits and risks must be defined.

Antimicrobial Efficiency of Aloe arborescens and Aloe barbadensis Natural and Commercial Products.

Nowadays, there are many commercial products from natural resources on the market, but they still have many additives to increase their biological activities. On the other hand, there is particular interest in natural sources that would have antimicrobial properties themselves and would inhibit the growth and the reproduction of opportunistic microorganisms. Therefore, a comparative antimicrobial study of natural samples of aloe and its commercial products was performed. Qualitative and quantitative determination of antimicrobial efficiency of Aloe arborescens and Aloe barbadensis and its commercial products on fungi, Gram-negative, and Gram-positive bacteria was performed. Samples exhibited antimicrobial activity and slowed down the growth of all tested microorganisms. Research has shown that natural juices and gels of A. arborescens and A. barbadensis are at higher added concentrations comparable to commercial aloe products, especially against microbial cultures of Bacillus cereus, Candida albicans, and Pseudomonas aeruginosa, whose growths were completely inhibited at a microbial concentration of 600 µg/mL. Of particular importance are the findings of the good antimicrobial efficacy of fresh juice and gel of A. arborescens on tested microorganisms, which is less known and less researched. These results show great potential of A. arborescens for further use in medicine, cosmetics, food, and pharmaceutical industries.

Nanocellulose in Drug Delivery and Antimicrobially Active Materials.

In recent years, nanocellulose (NC) has also attracted a great deal of attention in drug delivery systems due to its unique physical properties, specific surface area, low risk of cytotoxicity, and excellent biological properties. This review is focused on nanocellulose based systems acting as carriers to be used in drug or antimicrobial delivery by providing different but controlled and sustained release of drugs or antimicrobial agents, respectively, thus showing potential for different routes of applications and administration. Microorganisms are increasingly resistant to antibiotics, and because, generally, the used metal or metal oxide nanoparticles at some concentration have toxic effects, more research has focused on finding biocompatible antimicrobial agents that have been obtained from natural sources. Our review contains the latest research from the last five years that tested nanocellulose-based materials in the field of drug delivery and antimicrobial activity.

Generation Times of E. coli Prolong with Increasing Tannin Concentration while the Lag Phase Extends Exponentially.

The current study examines the effect of tannins and tannin extracts on the lag phase duration, growth rate, and generation time of Escherichia coli. Effects of castalagin, vescalagin, gallic acid, Colistizer, tannic acid as well as chestnut, mimosa, and quebracho extracts were determined on E. coli's growth phases using the broth microdilution method and obtained by turbidimetric measurements. E. coli responds to the stress caused by the investigated antimicrobial agents with reduced growth rates, longer generation times, and extended lag phases. Prolongation of the lag phase was relatively small at low tannin concentrations, while it became more pronounced at concentrations above half the MIC. Moreover, for the first time, it was observed that lag time extensions follow a strict exponential relationship with increasing tannin concentrations. This feature is very likely a direct consequence of the tannin complexation of certain essential ions from the growth medium, making them unavailable to E. coli for its growth.

The Effect of Growth Medium Strength on Minimum Inhibitory Concentrations of Tannins and Tannin Extracts against E. coli.

In this study the effect of growth medium strength on the minimum inhibitory concentration (MIC) of different tannins and tannin extracts against Escherichia coli was systematically investigated for the first time. Three pure compounds (vescalagin, castalagin and gallic acid) and five extracts (chestnut, quebracho, mimosa, Colistizer and tannic acid) were studied. Broth microdilution was assayed and bacteria were grown using different growth medium strengths varying from half to double the concentration recommended by the producer. MICs were determined using the iodonitrotetrazolium chloride (INT) dye or turbidity measurements. It was observed that MIC values depend on the growth medium strength. With an increase in the growth medium concentration MIC values rose roughly linearly for all samples, while their relative order remained unchanged, indicating that a direct interaction of tannins with growth medium nutrients represents the likely source of their antimicrobial activity. Understanding the effect of growth medium strength can finally yield a plausible explanation for the observed variation in MIC values reported in the scientific literature as well as provide help in planning proper applications of tannins in the livestock production.

Polyolefin/ZnO Composites Prepared by Melt Processing.

Composites of polyolefin matrices (HDPE and PP) were prepared by melt processing using two commercially available nano ZnO powders (Zinkoxyd aktiv and Zano 20). The mechanical and thermal properties, UV-Vis stability, and antibacterial activity of composites were studied. Tensile testing revealed that both nano ZnO types have no particular effect on the mechanical properties of HDPE composites, while some positive trends are observed for the PP-based composites, but only when Zano 20 was used as a nanofiller. Minimal changes in mechanical properties of composites are supported by an almost unaffected degree of crystallinity of polymer matrix. All polyolefin/ZnO composites exposed to artificial sunlight for 8-10 weeks show more pronounced color change than pure matrices. This effect is more evident for the HDPE than for the PP based composites. Color change also depends on the ZnO concentration and type; composites with Zano 20 show more intense color changes than those prepared with Zinkoxyd aktiv. Results of the antibacterial properties study show very high activity of polyolefin/ZnO composites against Staphylococcus aureus regardless of the ZnO surface modification, while antibacterial activity against Escherichia coli shows only the composites prepared with unmodified ZnO. This phenomenon is explained by different membrane structure of gram-positive (S. aureus) and gram-negative (E. coli) bacteria.

Chitosan-based (Nano)materials for Novel Biomedical Applications.

Chitosan-based nanomaterials have attracted significant attention in the biomedical field because of their unique biodegradable, biocompatible, non-toxic, and antimicrobial nature. Multiple perspectives of the proposed antibacterial effect and mode of action of chitosan-based nanomaterials are reviewed. Chitosan is presented as an ideal biomaterial for antimicrobial wound dressings that can either be fabricated alone in its native form or upgraded and incorporated with antibiotics, metallic antimicrobial particles, natural compounds and extracts in order to increase the antimicrobial effect. Since chitosan and its derivatives can enhance drug permeability across the blood-brain barrier, they can be also used as effective brain drug delivery carriers. Some of the recent chitosan formulations for brain uptake of various drugs are presented. The use of chitosan and its derivatives in other biomedical applications is also briefly discussed.

Release of Halophilic Extremozymes by Mechanical Cell Disruption.

Trimatostroma salinum, Wallemia ichthyophaga, Hortaea werneckii and Phaeotheca triangularis are halophilic fungi, which can thrive in a wide range of salinity. They present a source of valuable bioactive compounds, enzymes and proteins interesting for food and pharmaceutical industry. To separate enzymes from halophilic fungi cells, the mechanical method was used. Obtained results and new findings are important from the biotechnological point of view, since the separation of in the form of cocktail from halophilic fungi is interesting for industrial applications, especially for cascade reactions. Enzymes from extremophiles namely possess improved properties and can be used at harsh conditions where non-extremophilic enzymes may deactivate.

Enzyme Immobilization Onto Biochar Produced by the Hydrothermal Carbonization of Biomass.

For improving enzyme utilization in biotechnological processes, process costs have to be reduced, enzyme stability during industrial processes should be enhanced, and the recycle and reuse step should be favorable. The immobilization of enzymes is an important step for enhancing enzyme catalytic properties and operational stability. In order to reduce the costs of immobilization and consequently the cost of processes, a cheaper carrier (e.g. materials reclaimed as by-products) should be used. To achieve this, cellulase from Trichoderma sp. was immobilized on biochar obtained by low temperature hydrothermal carbonization (LTHTC) in two ways: by adsorption and by covalent binding via a crosslinking agent. The effect of immobilization time, enzyme concentration, type and concentration of the crosslinking agent and the types of carrier - biochar (LTHTC of waste from olive oil production (LTHTC of OL waste) or LTHTC of cellulose) on the immobilization efficiency and the residual activity of biocatalyst was studied. Higher immobilization efficiency and residual enzyme activity was achieved when the enzyme was covalently bound to biochar obtained by LTHTC of cellulose.

Use of Non-Conventional Cell Disruption Method for Extraction of Proteins from Black Yeasts.

The influence of pressure and treatment time on cells disruption of different black yeasts and on activities of extracted proteins using supercritical carbon dioxide process was studied. The cells of three different black yeasts Phaeotheca triangularis, Trimatostroma salinum, and Wallemia ichthyophaga were exposed to supercritical carbon dioxide (SC CO2) by varying pressure at fixed temperature (35°C). The black yeasts cell walls were disrupted, and the content of the cells was spilled into the liquid medium. The impact of SC CO2 conditions on secretion of enzymes and proteins from black yeast cells suspension was studied. The residual activity of the enzymes cellulase, ß-glucosidase, α-amylase, and protease was studied by enzymatic assay. The viability of black yeast cells was determined by measuring the optical density of the cell suspension at 600 nm. The total protein concentration in the suspension was determined on UV-Vis spectrophotometer at 595 nm. The release of intracellular and extracellular products from black yeast cells was achieved. Also, the observation by an environmental scanning electron microscopy shows major morphological changes with SC CO2-treated cells. The advantages of the proposed method are in a simple use, which is also possible for heat-sensitive materials on one hand and on the other hand integration of the extraction of enzymes and their use in biocatalytical reactions.

Optimisation of n-octyl oleate enzymatic synthesis over Rhizomucor miehei lipase.

Octyl oleate is a useful organic compound with several applications in cosmetic, lubricant and pharmaceutical industry. At first, the enzymatic synthesis of n-octyl oleate by direct lipase-catalysed esterification of oleic acid and 1-octanol was investigated in a stirred batch reactor in solvent-free system. A systematic screening and optimisation of the reaction parameters were performed to gain insight into the kinetics mechanism. Particularly, enzyme concentration, reaction temperature, stirrer speed, water content, substrates concentration and molar ratio were optimised with respect to the final product concentration and reaction rate. The kinetics mechanism of the reaction was investigated. Finally, a comparison of the experimental results obtained in a solvent free-system with those using two different solvents, supercritical carbon dioxide (SC-CO2) and n-hexane, was proposed. It resulted that in SC-CO2 higher concentration of the desired product was attained, requiring lower enzyme concentrations to achieve comparable conversion of free fatty acid into fatty acid ester.