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Degradation of Synthetic and Natural Textile Materials Using Streptomyces Strains: Model Compost and Genome Exploration for Potential Plastic-Degrading Enzymes
No full textGiven the environmental significance of the textile industry, especially the accumulation of
nondegradable materials, there is extensive development of greener approaches to fabric
waste management. Here, we investigated the biodegradation potential of three Streptomyces strains in model compost on polyamide (PA) and polyamide-elastane (PA-EA) as
synthetic, and on cotton (CO) as natural textile materials. Weight change of the materials
was followed, while Fourier-Transform Infrared Spectroscopy (FTIR) and Scanning Electron
Microscopy (SEM) were used to analyze surface changes of the materials upon biodegradation. The bioluminescence-based toxicity test employing Aliivibrio fischeri confirmed the
ecological safety of the tested textiles. After 12 months, the increase of 10 and 16% weight
loss, of PA-EA and PA, respectively, was observed in compost augmented with Streptomyces
sp. BPS43. Additionally, a 14% increase in cotton degradation was recorded after 2 months
in compost augmented with Streptomyces sp. NP10. Genome exploration of the strains was
carried out for potential plastic-degrading enzymes. It highlighted BPS43 as the most versatile strain with specific amidases that show sequence identity to UMG-SP-1, UMG-SP-2,
and UMG-SP-3 (polyurethane degrading enzymes identified from compost metagenome).
Our results showcase the behavior of Streptomyces sp. BPS43 in the degradation of PA and
PA-EA textiles in composting conditions, with enzymatic potential that could be further
characterized and optimized for increased synthetic textile degradation
High-Pressure Torsion and Anodic Oxidation as a Method for Surface Engineering of Ti-13Nb-13Zr Biomedical Alloy
No full textThe anodic oxidation technique was used for surface modification, resulting in the creation of a titanium-based nanotube oxide layer on a coarse-grained and ultrafine-grained Ti-13Nb-13Zr alloy. The modified surface morphology was analyzed using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The electrochemical impedance spectroscopy (EIS) method was employed to evaluate the corrosion stability of the Ti-13Nb-13Zr alloy before and after anodic oxidation. Corrosion stability was determined by exposing the examined alloy to a solution that simulates environment in the human organism (Ringer’s solution). To examine the titanium-based nanotube oxide layer adhesion on the Ti-13Nb-13Zr alloy’s surface, a scratch test was performed. The hydrophilicity of the modified surface was measured using the contact angle between a drop of Ringer’s solution and the modified surface. The anodic oxidation led to the creation of a nanotube oxide layer on the surface of the Ti-13Nb-13Zr (wt.%) alloy. The impact of the ultrafine-grained structure on the homogeneity of the nanotube oxide layer obtained using anodic oxidation was observed. The ultrafine-grained structure contributed to the increased diameter of the nanotubes, while the combined effect of anodic oxidation and high-pressure torsion significantly increased the roughness of the Ti-13Nb-13Zr alloy’s surface, which is expected to enhance biomechanical compatibility by reducing cytotoxicity, providing a more adaptable modulus of elasticity for human body conditions and ensuring adequate corrosion resistance and hydrophilicity. In this study, it was established that the examined alloy had suitable corrosion resistance for utilization in medicine as a metallic implant in the human body. The scratch test showed acceptable adhesion from the titanium-based nanotube oxide layer created using anodic oxidation. Also, the determination of the surface contact angle showed that the surface after anodic oxidation was more hydrophilic than the surface before anodic oxidation
Limit of detection variability in LC-MS/MS: A case study on pesticide residues in apples
No full textObjective
This study investigates the variability of limits of detection (LODs) in liquid chromatography–tandem
mass spectrometry (LC-MS/MS) resulting from the use of different calculation approaches.
Specifically, four calculation methods are compared, based on: (1) signal-to-noise ratio (S/N), (2)
standard deviation of the blank, (3) standard deviation of the residuals of the calibration curve, and (4)
standard deviation of the intercept of the calibration curve, as described in the ICH Q2(R2) guideline
[1]. Pesticide residues in apple samples were used as a case study to examine how LODs derived from
different calculation methods differ in terms of absolute value, inter-day variability, reproducibility,
and practical applicability.
Methods
LODs were determined for multiple pesticides commonly found in apple matrices. Sample preparation
followed the QuEChERS method. LC-MS/MS analysis was performed using a Dionex UltiMate 3000
HPLC system coupled with an LTQ XL (Thermo Fisher Scientific, USA), equipped with a linear ion
trap and electrospray ionization source, operating in multiple reaction monitoring mode. LODs were
calculated using S/N ratios from low-level matrix-matched standards, standard deviations from
replicate injections of matrix-matched blanks, and parameters derived from regression analysis of
matrix-matched calibration curves. Experiments were repeated over five days to assess reproducibility.
Results
LODs varied significantly depending on the calculation approach. For most pesticides, the lowest
LODs were obtained using the S/N method, while the highest values resulted from the standard
deviation of residuals. The approaches based on regression analysis of calibration curves showed the
best inter-day reproducibility, with the intercept-based method yielding slightly somewhat lower LODs
than those calculated from the residuals. Among the evaluated approaches, the intercept-based method
was selected as the most appropriate, as the LOQs derived from these LODs demonstrated satisfactory
reproducibility in practice, in line with the SANTE/2020/12830 guideline [2].
Conclusions
The choice of LOD calculation method significantly influences the reported values and their
reproducibility. Based on our results, the approach using the standard deviation of the intercept of the
calibration curve is recommended, as it provided consistent LODs and led to LOQs with
reproducibility suitable for routine quantitative analysis
Integrated extraction and enzymatic hydrolysis for emerging prebiotic production from agro-industrial waste
No full textIntroduction: Due to its availability and abundance, lignocellulosic biomass
(LCB) has become a feedstock of interest for obtaining a variety of products,
such as biofuel and food additives [1]. Xylo-oligosaccharides (XOS) and
cello-oligosaccharides (COS) are considered emerging prebiotics - a class of
food additives which exhibit beneficial effects on human health [1]. These
products are traditionally derived from LCB through chemical processes at
harsh conditions, which generate toxic by-products and can have a negative
environmental impact. Moreover, the majority of these processes rely on
multiple pretreatment steps, which only aim to reduce LCB recalcitrance,
without generating any products [2]. This work presents a novel biocatalytic
process for simultaneous XOS and COS production based on the integrated
liquid-solid extraction and enzymatic hydrolysis, using sunflower residues as
raw material. In line with the biorefinery concept, raw material was obtained
after the pretreatment of sunflower meal designed to obtain value-added
products, namely phenolics-rich extract and protein hydrolysate. Compared
to the traditional methods, this process represents a green and sustainable
solution with improved product quality, which could become industrially
relevant..
Investigating the bioactive properties of microwave pretreated gluten hydrolysate fractions obtained via ultrafiltration
No full textA suspension of gluten from wheat was pretreated in a microwave reactor (Anton Paar
Monowave 300) with the power of 200 W and afterwards subjected to enzymatic hydrolysis
(final gluten concentration of 2% (w/w)) with Alcalase at 60 °C, while a control hydrolysis
was performed without microwave pretreatment under the same conditions. The obtained
hydrolysates were further separated by a pressurized ultrafiltration stirred cell (Millipore 8050
unit) with cellulose membranes with different pore sizes, 1–30 kDa. By consecutively
applying several different cellulose membranes, we were able to perform a multistep
separation process of hydrolyzed gluten peptides in order to investigate their bioactive
properties, such as ABTS•+ and DPPH• neutralization, and Fe2+ chelating ability. The
ABTS•+ and DPPH• neutralization properties of the produced gluten hydrolysates showed no
significant differences among the tested fractions, while the ability to chelate Fe2+ ions is
particularly noteworthy. Fe2+ ion chelating activities of the obtained fractions (F1-F5)
showed that microwave pretreated hydrolysate fractions F2 (10-30 kDa), F3 (3-10 kDa) and
F4 (1-3 kDa) were the main carriers of the bioactivity, with Fe2+ chelating activities ranging
from 50–60%. A 10-25% increase of Fe2+ chelating activity was recorded for the microwave
pretreated hydrolysate fractions in comparison to the control. It was concluded that the
microwave pretreatment of gluten had significant effect on the Fe2+ chelating activity of the
obtained hydrolysate fractions. No significant differences were recorded for the DPPH•
neutralization, besides the control sample F1 (> 30 kDa) fraction. The ultrafiltration
separation process showed that microwave pretreatment had improved the Fe2+ chelating
activity, for the values recorded between the same fraction size of the two hydrolysates. The
implementation of microwave pretreatment may be further utilized to produce effective
smaller-sized bioactive peptides
Macerated plant extracts as a sustainable alternative for corrosion protection of aluminium in chloride environment
No full textThis study comprises the extraction and characterisation of plant extracts derived from (i) Thymus serpyllum, (ii)
Ocimum basilicum, and (iii) Satureja montana. Extracts were prepared by a maceration process using three solvents: distilled water, ethanol, and a water-ethanol mixture. Phytochemical analysis revealed significant variations in total phenolic, flavonoid, triterpenoid, and coumarin contents, with optimal extraction conditions
differing among plant species and solvents used for extraction. First, the antimicrobial activity of extracts was
investigated. Extracts selectively inhibited Staphylococcus aureus growth but not Pseudomonas aeruginosa. Then,
an electrochemical investigation was conducted to assess the potential of plant extracts as corrosion inhibitors for
aluminium in 0.1 M NaCl solution. S. montana water extract exhibited the most promising corrosion protection.
Long-term immersion tests measured by electrochemical impedance spectroscopy and potentiodynamic polarisation showed that S. montana extracts enhanced aluminium’s resistance to corrosion over time, seen as an
increase in impedance magnitude and a broader passivity region. Surface characterisation via scanning electron
microscopy and Fourier-transform infrared spectroscopy confirmed the adsorption of phytochemicals and formation of a protective layer on the aluminium surface. This study is the first to demonstrate the significant
corrosion inhibition effect of S. montana extracts on aluminium, highlighting its potential as a sustainable
alternative for corrosion protection
Geopolymers Based on Fly Ash for Organic Dye Removal from Water
No full textThe main goal of this study is to address the problem of environmental water pollution caused by organic dyes through waste valorization by synthesizing geopolymer-based adsorbents. In this work, geopolymers were synthesized using fly ash modified with chitosan and polyvinyl alcohol as a starting material. The obtained materials were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and determination of the point of zero charge. We examined the adsorption potential for organic dye (methylene blue, brilliant green, crystal violet) removal through the influence of contact time, initial pH and concentration of adsorbate solution, and temperature on adsorption. The obtained results were analyzed using theoretical kinetics and isotherm models. Interpretation of the obtained results was performed using the Box–Behnken design and chemometric methods of multivariate analysis. The findings showed that modification with chitosan significantly enhanced the adsorption efficiency of the synthesized materials up to 95.9% for methylene blue adsorption. The parameters identified as having the greatest influence on the adsorption process were contact time, pH-value, initial dye concentration, and the type of dye being adsorbed
Application Possibilities and Expected Effects of Dissolved Air Flotation in Groundwater Treatment for Removing TOC, Color and As
No full textThe design of a water treatment plant requires thorough analysis of water quality, capacity, location, and reliable technologies. Groundwater sources with elevated levels of organic matter, color, arsenic, and dissolved gases represent a particular challenge for treatment. In this study, the application of dissolved air flotation (DAF) was systematically investigated as a pretreatment method for groundwater purification. Jar test experiments were conducted to evaluate the removal of total organic carbon (TOC), color, and arsenic under various coagulant dosages. The results demonstrated that DAF achieved up to 65% TOC removal and significant arsenic reduction, while also improving water color. Compared with conventional pretreatment, optimized DAF conditions provided higher efficiency and practical applicability for real-world water treatment plant design. The findings highlight the potential of DAF as an effective technology for addressing complex groundwater contamination and contribute to expanding its use beyond conventional surface water treatment
Development and Structural Characterization of Pullulan/Lecithin/Zein Composite Nanofibers Loaded with Mountain Germander (Teucrium montanum) Polyphenolic Extract
No full textIn this study, the electrospinning technique was employed to encapsulate mountain germander (MG) polyphenolic extract into pullulan/zein (PUL:ZE) delivery systems stabilized with sunflower lecithin. The rheological and physical properties of the pullulan (PUL), PUL:ZE, and zein (ZE) polymer solutions were evaluated to assess their electrospinnability potential. Fabricated nanofibers were then characterized for their morphology, physicochemical, and thermal properties, as well as encapsulation efficiency and simulated in vitro digestion. The elastic component of the polymer solution, quantified by the Deborah number, showed a strong correlation with nanofiber diameter (r = 0.75). FT-IR spectra confirmed the role of sunflower lecithin as a mediator in the formation of hydrogen and hydrophobic interactions among PUL, ZE, and polyphenols. The circular dichroism spectra confirmed the influence of the MG extract on the change in the secondary conformation of the protein structure. The PUL:ZE delivery matrix proved to be suitable for the retention of phenylethanoid glycosides (encapsulation efficiency > 73%). The formulation 50PUL:50ZE was found to have the highest potential for prolonged release of polyphenols under gastrointestinal in vitro conditions. These findings propose a water-based electrospinning approach for designing polyphenolic delivery systems stabilized with lecithin for potential applications in active food packaging or nutraceutical products
Influence of Washing on Comfort Properties of Woven Fabrics Intended for Reusable Protective Clothing for Medical Personnel
No full textIn this work, the influence of washing on the comfort properties of woven fabrics intended for reusable protective clothing used by medical personnel was investigated. More specifically, three different woven fabrics based on cotton in twill 3/1 weave, cotton/polyester blend in twill 2/1 weave, and cotton/polyester blend in twill 3/1 weave were investigated. Their comfort properties (air permeability, water vapor transmission rate, volume electrical resistivity, compressibility, and compressive resilience) were monitored before and after 60 washing cycles. To better understand the changes in their comfort properties caused by washing, their structural characteristics (number of threads per unit length, warp and weft crimp, mass per unit area, and thickness) and electrokinetic (zeta potential) properties were also evaluated before and after 60 washing cycles. All investigated woven fabrics showed decreased air permeability and water vapor transmission rate, as well as increased volume electrical resistivity after 60 washing cycles. Woven fabric based on cotton in a twill 3/1 weave showed reduced compressibility and increased compressive resilience after 60 washing cycles. In contrast, woven fabrics based on cotton/polyester blend in twill 2/1 and 3/1 weave showed increased compressibility and decreased compressive resilience after 60 washing cycles