Search Results (47)

Hydrogen (H₂) is becoming a meaningful way to store energy for long-term use and support thorough decarbonization in systems that use renewable energy. Underground hydrogen storage (UHS) has strategic benefits over above-ground systems because it can hold large volumes, is contained by geology, and is cheap to operate in cycles. This review compares four key geological formations for underground hydrogen storage (UHS): salt caverns, lined rock caverns, depleted hydrocarbon reservoirs, and saline aquifers. Each system is evaluated based on storage mechanisms, efficiency, safety, technological maturity, and economic feasibility. This review also introduces a unified cross-media evaluation framework, a TRL-risk matrix, a technology development roadmap, and novel insights into AI-based monitoring, offering prescriptive guidance for large-scale UHS implementation. Salt caverns have high injectivity, maintain their purity, and undergo 6 to 12 cycles per year at pressures of 60 to 180 bar; however, they are only found in certain places. Lined rock caverns can be built anywhere, but sealing and economic issues make them difficult to use. Depleted hydrocarbon reservoirs with TWh-scale capacity and already built infrastructure. Saline aquifers, on the other hand, have the most potential in the world but need enhanced management of microbiological responses and cushion gas optimization. A synthesis of current studies highlights key research gaps in cyclic geomechanics, hydrogen–rock–microbe interactions, and liner performance for high-pressure storage. The review concludes with techno-economic and safety considerations and identifies future directions for deploying geological UHS as a critical component of a net-zero hydrogen economy. Full article

Bacterial endospores are highly resistant, dormant forms that pose persistent challenges in food safety, environmental microbiology, and industrial hygiene. Accurate evaluation of endospore resistance, physiology, and inactivation depends on both purification and detection methods; however, these processes are typically examined independently, limiting methodological consistency and contributing to variability across studies. In this review, current approaches for endospore purification and detection are critically examined, including washing-based methods, density gradient centrifugation, enzymatic treatments, culture-based enumeration, molecular assays, flow cytometry, and emerging biosensor technologies. In addition, these methods are compared using metrics such as purity, recovery yield, sensitivity, and specificity, and their advantages and limitations are summarized to clarify performance. It is further proposed that endospore purification and detection should be considered as a single, end-to-end analytical workflow and optimized accordingly. Purification strategies influence sample cleanliness and aspects of endospore quality, including viability, structural integrity, and physiological state, which affect detection performance and quantitative accuracy. Based on this integrated perspective, a conceptual framework linking purification efficiency to detection outcomes is presented, along with practical considerations for method selection across relevant application contexts. Finally, gaps in standardization are identified, and future research directions are outlined to improve reproducibility and cross-study comparability in endospore-related studies. Full article

Dietary supplements, especially lycopene-containing ones, are of interest because of their antioxidant and potential health-promoting effects; however, their actual composition and safety have not been sufficiently verified. This study evaluated the accuracy of labelled lycopene content and assessed selected chemical and microbiological safety parameters in commercially available products. Lycopene levels were determined spectrophotometrically and by HPLC, whereas pesticide residues, heavy metals, and microbiological purity were analysed using validated regulatory-compliant methods. Marked inconsistencies were found between the declared and measured lycopene content, with HPLC revealing concentrations up to 70% above label claims. Methomyl (0.059 mg/kg), a pesticide not approved in the EU, was detected in one supplement, heavy metal concentrations met current regulatory limits, and other elements remained below quantification thresholds. Microbiological quality was satisfactory, with low total viable counts and absence of pathogens, yeasts, and moulds; only low levels of environmental spore-forming bacteria were detected. The findings highlight acceptable microbiological and elemental safety but reveal substantial deviations in lycopene content labelled/determined and the presence of a non-approved pesticide (however, below the MRL). A comprehensive multi-parameter quality assessment is essential to ensure the safety, reliability, and regulatory compliance of lycopene supplements. Full article

The growing demand for clean-label, plant-based foods is accelerating the development of vegan emulsified products that avoid synthetic additives while delivering appealing sensory and health-related attributes. We formulated naturally colored, mayonnaise-like oil-in-water emulsions using 55% canola oil and yeast protein extracts (YPEs) as emulsifiers and polyphenol-rich ingredients derived from red cabbage and butterfly pea flower. The resulting systems were characterized for rheological behavior, texture, droplet-size distribution, lipid oxidation (peroxide value) and microbiological stability. Two distinct YPEs produced emulsions with different microstructural and mechanical properties, highlighting the role of protein composition on emulsion architecture. Incorporation of anthocyanin-rich polyphenol matrices (red cabbage extracts characterized by predominantly simple acylations and butterfly pea flower extracts containing complex acylations, both at similar purities) modulated emulsion structuring and stability during storage, beyond color delivery. Overall, polyphenol addition strengthened emulsion structure, as evidenced by a significant increase in plateau modulus from 621 Pa to 1428 Pa in emulsions with complete YPE and butterfly pea extract and mitigated lipid oxidation, supporting their use as partial replacement options for additives such as EDTA in clean-label formulations. These findings provide a practical basis for designing functional, and visually attractive vegan emulsions that align with consumer demand for additive-reduced products. Full article

Probiotics are live microorganisms that provide health benefits when administered in adequate amounts. Due to the increasing popularity of probiotic supplements, concerns have arisen regarding their quality, microbial composition, and safety. This study aimed to evaluate the quantitative and qualitative characteristics of the selected probiotics available on the Polish market, including both dietary supplements and foods for special medical purposes, and to compare the obtained results with the information provided on the product labels. Fifteen commercial probiotic products were analysed. Viable microorganism counts were determined using the traditional culture-based plate count method and by flow cytometry for selected products. Species identification was performed using MALDI-TOF MS and qPCR, whereas microbiological purity testing was conducted to confirm the absence of pathogenic bacteria. Significant differences were observed between the declared and experimentally determined numbers of viable microorganisms. Only a few products maintained bacterial counts consistent with label claims, while most contained considerably low viable cells. Flow cytometry revealed higher viable cell counts than plate counting, indicating the presence of viable but non-culturable bacteria. The declared species composition of the strains was mostly confirmed, although in several cases, undeclared probiotic microorganisms were identified. All tested products were free from pathogens. The study indicates significant discrepancies in the quality of probiotic supplements available on the Polish market. From a consumer perspective, these findings highlight the importance of verifying probiotic quality and suggest that not all commercial products may guarantee the full range of claimed health benefits. The implementation of standardised analytical procedures and enhanced quality control measures is therefore essential to ensure the product safety, strain authenticity, and reliability of health-related claims. Full article

Introduction: Teeth intended for use as autogenous augmentative material may carry microbiological contamination, which can compromise the safety of regenerative procedures in the oral cavity. Therefore, effective disinfection protocols are crucial to ensure the microbiological purity of dentin-derived graft materials. Objective: This study aimed to evaluate the effectiveness of a 30% alkaline ethanol solution containing 0.5 M sodium hydroxide in eliminating microorganisms from dentin material intended for autogenous augmentation. Materials and Methods: The study included 44 extracted teeth that were processed using the Smart Dentin Grinder procedure. The presence of microorganisms was analysed using standard microbiological methods before and after treatment with the disinfectant solution. Additionally, the potential association between tooth eruption status and the effectiveness of the disinfection process was evaluated using Fisher’s exact test, with odds ratios calculated using the Haldane–Anscombe correction to address zero cell counts. Results: Processing dentin in a 30% alkaline ethyl alcohol solution containing 0.5 M sodium hydroxide is an effective method for eliminating microorganisms, thereby rendering the material completely microbiologically pure. Conclusions: The dentine processing procedure used appears to ensure the production of autogenous material free from microbiological contamination, indicating its potential safety in clinical applications. Full article

In this study, the authors focus on optimizing the processing parameters for the fabrication of biodegradable polymer filaments intended for subsequent 3D printing of biomedical structures and implants. Following extrusion and additive manufacturing, the produced materials underwent a comprehensive evaluation that included mechanical, microbiological, biofilm formation, and electron microscopy analyses. The complexity of these tests aimed to determine the potential of the developed materials for biomedical applications, particularly in the field of scaffold fabrication. At the initial stage, three types of filaments (technical designations 111, 145, and 146) were produced using Fused Filament Fabrication (FFF) technology. These filaments were based on a PLA/PHB matrix with varying types and concentrations of plasticizers. Standardized destructive tensile and compressive mechanical tests were conducted using an MTS Insight 1 kN testing system equipped with an Instron 2620-601 extensometer. Among the tested samples, the filament labeled 111, composed of PLA/PHB thermoplastic starch and a plasticizer, exhibited the most favorable mechanical performance, with a Young’s modulus of elasticity of 4.63 MPa for 100% infill. The filament labeled 146 had a Young’s modulus of elasticity of 4.53 MPa for 100% infill and the material labeled 145 had a Young’s modulus of elasticity of 1.45 MPa for 100% infill. Microbiological assessments were performed to evaluate the capacity of bacteria and fungi to colonize the material surfaces. During bacterial activity assessment, we observed biofilm formation on the examined sample surfaces of each material from the smooth and rough sides. The colony-forming units (CFUs) increased directly with the exposure time. For all samples from each material, the Log10 (CFU) value reached above 9.41 during 72 h of incubation for the activity of each type of bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans). Scanning electron microscopy provided insight into the surface quality of the material and revealed its local quality and purity. Surface defects were eliminated by this method. Overall, the results indicate that the designed biodegradable filaments, especially formulation 111, have promising properties for the development of scaffolds intended for hard tissue replacement and could also be suitable for regenerative applications in the future after achieving the desired biological properties. Full article

Background: To meet the urgent need for novel antibacterial agents that are active also against worrying superbugs, natural pentacyclic triterpenoids, including totally inactive betulin (BET) and betulinic acid (BA), as well as ursolic acid (UA), active on Gram-positive bacteria, have been chemically modified, achieving compounds 1–7. Methods: Triterpenoid derivatives 1–7 and all synthetic intermediates were characterized by chemometric-assisted FTIR and NMR spectroscopy, as well as by other analytical techniques, which confirmed their structure and high purity. Minimum inhibitory concentration values (MICs) of 1–7, BET, BA and UA were determined by the broth dilution method, using a selection of Gram-positive and Gram-negative clinically isolated superbugs. Results: Performed experiments evidenced that compounds 4–7 had potent antibacterial effects against Gram-positive methicillin-resistant Staphylococcus aureus and S. epidermidis (MRSA and MRSE), as well as against vancomycin-resistant Enterococcus faecalis and E. faecium (VRE). The antibacterial effects of 4–7 were due to the insertion of a triphenyl phosphonium (TPP) group and were higher than those reported so far for other BET, BA and UA derivatives, especially considering the complex pattern of resistance of the isolates used here and their clinical source. Conclusions: For the first time, by inserting TPP, a real activity (MICs 2–16 µg/mL) was conferred to inactive BET and BA (MICs > 1024 and 256 µg/mL). Moreover, the antibacterial effects of UA were improved 16- and 32-fold against MRSE and MRSA (MICs = 2 vs. 32 and 64 μg/mL). Future Perspectives: Based on these very promising microbiologic results, new experiments are currently underway with the best-performing compounds 5 and 7 (MICs = 2 μg/mL) on an enlarged number of Gram-positive isolates, to confirm their MICs. Moreover, investigations about their possible antibiofilm activity, time-killing curves and cytotoxicity on eukaryotic cells will be carried out to define their pharmacological behavior and clinical potential. Full article

Mixed municipal solid waste (MSW) of cities and tourist-heavy areas typically contains elevated amounts of recyclable materials. In Austria, numerous material recovery facilities exist for processing this waste; however, they primarily focus on separating metals, neglecting the recovery potential of other recyclables. To evaluate such potential for polyolefins and paper-based materials, two pilot-scale trials were conducted in a model region in Tyrol, Western Austria, accompanied by comprehensive sampling, waste characterisation, and material flow analysis. Pre-concentrates with up to 70% purity were obtained using two stages of near-infrared sorting, although challenges arose due to the presence of textiles and composite materials. This study found that separating polyolefins from mixed MSW could increase recycling rates in the region by up to 16% (absolute). Paper recovery also showed a modest increase. Polyolefin recovery slightly lowered, whereas paper recovery moderately raised the heating value. Recycling such materials is technically feasible, and forthcoming legislative changes are expected to create a market for these materials. Although fundamental questions remain regarding the optimal balance between recycling and refuse-derived fuel, as well as concerns about microbiological or chemical hazards, it can enhance resource efficiency, develop circularity, and aid comparison in regions with similar demographic and tourism characteristics. Full article

This study investigates contaminants in metalworking fluids (MWFs) from an industrial band saw, focusing on microparticle classification and microbial quantification linked to fluid degradation. Most particles were under 50 µm, primarily aluminum and iron oxides from tool wear; oxygen- and sulfur-containing particles suggested corrosion. Microbiological analysis showed high contamination, with culturable microorganisms exceeding 1000 CFU/mL. A pathogenic strain associated with biodeterioration was identified, underscoring the need for microbial control. Filtration and ozonation have been used as decontamination methods to improve the purity and biological stability of the process fluid. Filtration enabled selective removal of metallic microparticles. Among six nanofiber filters, the Berry filter achieved the highest efficiency (70.8%) for particles ≥ 7.3 µm, while other filters were faster but less efficient. Ozonation proved highly effective for microbiological decontamination, reducing viable microorganisms by over 95%, improving visual clarity, and lowering pH from 9 to 8 while remaining within operational limits. Unlike filtration, ozonation significantly reduced microbial load. The combination of both methods is proposed as a sustainable strategy for maintaining process fluid quality under industrial conditions. These findings support integrated decontamination approaches to extend fluid life, reduce fresh MWF consumption and waste, and enhance workplace hygiene and safety in machining operations. Full article

Medicinal products available on the market should be characterised by therapeutic efficacy, high quality, and safety for patients. They must either be sterile or comply with the appropriate pharmacopoeial microbiological purity requirements. Pharmacopoeial monographs related to microbiological tests of drug quality were also referenced. Despite stringent regulations governing pharmaceutical production, irregularities in the microbiological quality of drugs still occur. These are monitored by relevant agencies, which may order the recall of defective product batches from the market. However, in recent years, numerous cases of microbiological contamination in drugs and drug-related infections have been reported. Both isolated incidents and larger outbreaks or epidemics linked to contaminated medicines have been documented. Various microorganisms, including Gram-negative and Gram-positive bacteria, anaerobes, and yeast-like and mould fungi, have been identified in medicinal products or in patients affected by contaminated drugs. Ensuring the appropriate purity or sterility of pharmaceutical raw materials; maintaining cleanliness in the manufacturing environment, facilities, and equipment; and adhering to hygiene protocols and Good Manufacturing Practice regulations are essential for the production of safe and high-quality medicinal products. The aim of this study is to collect and compile information on the microbiological quality of drugs available on the market, with particular attention to identified irregularities, objectionable microorganisms isolated from medicinal products, and drug-related infections. Full article

Eugenol (EU) and isoeugenol (IZO-EU) are naturally occurring compounds known for their strong antibacterial properties, which makes them ideal candidates for application as preservatives in cosmetic products. Primarily derived from clove oil, EU demonstrates potent antibacterial effects against a wide range of microorganisms, including Gram-positive and Gram-negative bacteria, as well as yeast-like fungi such as Candida albicans. Their antibacterial action is mainly connected with their ability to disrupt microbial cell membranes and inhibit key enzymatic processes. IZO-EU, a structural isomer of EU, also shows significant activity against various pathogens. In these studies, the effectiveness of EU and IZO-EU as preservatives in cosmetic formulations was tested. The antibacterial activity tests, using the disk diffusion method, assessed their effectiveness against Enterococcus faecalis, Staphylococcus aureus (Gram-positive), Escherichia coli, Pseudomonas aeruginosa (Gram-negative), and Candida albicans. Creams containing the different concentrations of EU and IZO-EU (0.5%, 1.5%, 2.5%) were tested for microbiological purity, texture, consistency, and stability over a defined storage period and under controlled conditions (temperature, humidity, and light exposure). Microbiological purity was assessed through the standard culture methods, while the texture and consistency were evaluated using rheological measurements and sensory analysis. The obtained results demonstrated that both compounds effectively preserved the creams, maintaining the microbiological purity without significantly altering the texture, consistency, or stability throughout the storage period. Additionally, EU and IZO-EU not only enhanced the antibacterial protection of the formulations but also contributed to the pleasant fragrance. Furthermore, preliminary studies were conducted on their anticancer properties using the LoVo (colon cancer) and U87MG (glioma) cell lines. These studies revealed the hormetic effects at the low concentrations and cytotoxicity at the higher doses, suggesting that EU and IZO-EU may have therapeutic potential beyond cosmetic applications. These studies support the application of EU and IZO-EU as natural, multifunctional ingredients in cosmetics, offering both preservative and sensory benefits while meeting the growing consumer demand for natural and sustainable solutions in the beauty industry. Full article

Introduction: The official implementation of pharmaceutical-grade cannabis raw materials for medicinal use has permitted doctors to prescribe and pharmacists to prepare cannabis-based formulations. The objective of the pharmaceutical development and manufacturing process optimization work was to propose a suppository formulation containing doses of 25 mg and 50 mg of tetra-hydrocannabinol (∆-9-THC) as an alternative to existing inhalable or orally administered formulations. The formulation could be used for rectal or vaginal administration, thereby providing dosage control in the treatment of endometriosis and other conditions involving pain. In this study, two substrates from suppositories with standardized Cannabis extractum normatum (CEX) were used: cocoa butter and Witepsol^® H15. Materials and Methods: The long-term stability of CEX was investigated over a period of up to 24 months. The concentrations of ∆-9-THC, cannabidiol (CBD), and cannabinol (CBN) were determined using an HPLC method. Furthermore, the water content of the extract, the ethanol residue, and the microbiological purity were determined. The pharmaceutical properties of CEX-incorporated suppositories, namely content uniformity, hardness, softening time, total deformation time, disintegration time, and the release profile of ∆-9-THC, CBD, and CBN, were evaluated in order to develop optimal preparation procedures for pharmacists. Results and Discussion: Following a 24-month stability study on CEX, no significant alterations in component content were observed beyond the specified requirements. The disintegration time, total deformation time, and hardness of the suppositories based on Witepsol^® H15 with CEX were found to be longer and higher, respectively, than those of suppositories formulated with cocoa butter. In vitro studies demonstrated that suppositories prepared with Witepsol^® H15 exhibited superior release of ∆-9-THC compared to those prepared with cocoa butter. Conclusions: We suggest that pharmacists making prescription drugs in a pharmacy setting in the form of medical marijuana suppositories will receive a better release profile of the drug by choosing Witepsol® H15 as a substrate. Full article

Wearing masks to protect against communicable diseases is an effective tool used in many countries affected by the COVID-19 pandemic. The antibacterial activity, antibacterial efficiency, microbial purity, and breathability properties of medical disposable masks are very important. Ag is most commonly applied to antimicrobial textiles. In this work, three antimicrobial additives were used. Four compositions of the binders with antimicrobial additives were prepared and applied to one-layer non-woven PP material. The influence of the binder antimicrobial polymer coating on the breathability and antibacterial activity of the non-woven PP material was evaluated. The results show that the composition of the polyacrylic acid binder had the least effect on their breathability and samples with the silver chloride formulation showed the best antimicrobial response. Based on the microbiological and air permeability results of the samples of the one-layer non-woven material with coating, the samples of two layers and three layers of the medical mask model were prepared. Microbiological studies have shown that a three-layered medical mask model with silver chloride composition in the middle layer, on both sides of the model, has antibacterial efficiency against three pathogens (E. Coli, K. Pneumoniae, and S. Aureus). The performance of this medical mask model has been found to meet the requirements for type I medical masks according to the EN 14863 standard. Studies have shown that the microbial purity of the mask model is CFU/g < 3. Full article

Plant peptidase inhibitors play crucial roles in plant defence mechanisms and physiological processes. In this study, we isolated and characterised a Kunitz trypsin inhibitor from Enterolobium gummiferum seeds named EgPI (E. gummiferum peptidase inhibitor). The purification process involved two chromatography steps using size exclusion and hydrophobic resins, resulting in high purity and yield. EgPI appeared as a single band of ~20 kDa in SDS-PAGE. Under reducing conditions, the inhibitor exhibited two polypeptide chains, with 15 and 5 kDa. Functional characterisation revealed that EgPI displayed an inhibition stoichiometry of 1:1 against trypsin, with a dissociation constant of 8.4 × 10⁻⁹ mol·L⁻¹. The amino-terminal sequencing of EgPI revealed the homology with Kunitz inhibitors. Circular dichroism analysis provided insights into the secondary structure of EgPI, which displayed the signature typical of Kunitz inhibitors. Stability studies demonstrated that EgPI maintained the secondary structure necessary to exhibit its inhibitory activity up to 70 °C and over a pH range from 2 to 8. Microbiological screening revealed that EgPI has antibiofilm properties against pathogenic yeasts at 1.125 μmol·L⁻¹, and EgPI reduced C. albicans biofilm formation by 82.7%. The high affinity of EgPI for trypsin suggests potential applications in various fields. Furthermore, its antibiofilm properties recommended its usefulness in agriculture and antimicrobial therapy research, highlighting the practical implications of our research. Full article