Search Results (104)

Previous studies have demonstrated that Bacillus velezensis HN-Q-8 shows significant inhibitory effects against various plant pathogenic fungi causing potato diseases, primarily attributed to the production of fengycin. However, the low yield of fengycin in wild-type strains limits its practical application, and the influence of its biosynthesis pathway on volatile organic compound production remains unclear. In this study, to enhance fengycin production in Bacillus velezensis HN-Q-8, we applied metabolic engineering by targeting competitive pathways. Specifically, a double mutant (ΔsrfAAΔbaeBE) was constructed by knocking out the surfactin synthase gene srfAA and the bacillaene synthesis gene baeBE. The fengycin yield of the ΔsrfAAΔbaeBE mutant in the basal (sodium glutamate) fermentation medium reached 98.83 mg/L, representing a 2.39-fold increase over the wild-type strain. Subsequent medium optimization by supplementing peptone further boosted production to 155.61 mg/L, which was 3.77-fold higher than the wild-type level. The lipopeptide extract from the double mutant strain ΔsrfAAΔbaeBE demonstrated potentiated antifungal activity against four major potato fungal pathogens: Alternaria solani (early blight), Rhizoctonia solani (black scurf), Fusarium oxysporum (wilt), and Botrytis cinerea (gray mold). The active volatile compounds released by ΔsrfAAΔbaeBE, such as benzaldehyde and 2,5-dimethylpyrazine were significantly increased. The knockout of srfAA and baeBE also distinctly altered the physiology of the strain: the double mutant exhibited enhanced biofilm formation, an accelerated early growth rate followed by early decline, and a severely reduced sporulation capacity. These results confirmed the feasibility of molecularly modifying Bacillus velezensis HN-Q-8 to improve fengycin production and antifungal activity for further agricultural application. Full article

Polyester fibers are extensively used in textiles, packaging, and industrial applications due to their durability and excellent mechanical properties. However, high-crystallinity polyester fibers represent a major challenge in plastic waste management due to their resistance to biodegradation. This study evaluated the biodegradation potential of environmental Bacillus isolates, obtained from mold-contaminated black bean plastic bags, toward polyethylene terephthalate (PET) and industrial-grade polyester fibers under mesophilic conditions. Among thirteen isolates, five (Bacillus altitudinis N5, Bacillus subtilis N6, and others) exhibited measurable degradation within 30 days, with mass losses up to 5–6% and corresponding rate constants of 0.04–0.05 day⁻¹. A combination of complementary characterization techniques, including mass loss analysis, scanning electron microscopy (SEM), gel permeation chromatography (GPC), and gas chromatography/mass spectrometry (GC/MS), together with Fourier-transform infrared spectroscopy (FTIR), thermogravimetric/differential scanning calorimetry (TGA/DSC), and water contact angle (WCA) analysis, was employed to evaluate the biodegradation behavior of polyester fibers. Cross-analysis of mass loss, surface morphology, molecular weight reduction, and degradation products suggests a surface erosion-dominated degradation process, accompanied by ester-bond hydrolysis and preferential degradation of amorphous regions. FTIR, TGA/DSC, and WCA analyses further reflected chemical, thermal, and surface property changes induced by biodegradation rather than directly defining the degradation mechanism. The findings highlight the capacity of mesophilic Bacillus species to partially depolymerize polyester fibers under mild environmental conditions, providing strain resources and mechanistic insight for developing low-energy bioprocesses for polyester fiber waste management. Full article

Asthma continues to affect millions of adults in the United States, with indoor environmental exposures playing a major role in symptom burden and control. Limited research has examined the combined influence of multiple household and environmental determinants on adult asthma morbidity, particularly in diverse states such as Texas. We analyzed pooled data from 1596 Texas adults with asthma who completed the Asthma Call-Back Survey between 2019 and 2022. Multivariable logistic regression models, adjusted for survey design and demographic covariates, were used to examine associations between household and environmental determinants and four morbidity outcomes: asthma attacks, recent symptoms, sleep difficulty, and limited activity due to asthma. Current smoking, lack of bathroom or kitchen ventilation, and absence of air purifier use were consistently associated with higher odds of morbidity. Protective associations were observed for homes without mold, rodents, or furry pets. Disparities were also evident, with older adults, women, and non-Hispanic Black respondents reporting greater morbidity. These findings highlight the importance of addressing modifiable exposures such as indoor smoking, ventilation, and allergen control within comprehensive asthma management strategies. Targeted interventions that combine environmental modifications with health education may help reduce asthma disparities and improve the quality of life for adults with asthma. Full article

Dendrochronology serves as a vital tool for analyzing the long-term interactions between commercial timber growth and environmental variables such as soil, water, and climate. This study presents Dendro-AutoCount, an innovative image processing framework designed for identifying obscured tree rings in cross-sectional images of Pinus taeda L. The methodology integrates Hessian-based ridge detection with a weighted radial voting gradient method to precisely locate the pith. Following pith detection, the system performs radial cropping to generate directional sub-images (north, east, south, west), where rings are identified via intensity profile analysis, signal smoothing, and peak detection. By filtering outliers and averaging directional counts, the system effectively mitigates common visual interference from black molds, fungus, structural cracks, buds, knots, and cracks. Experimental results confirm the high efficacy of Dendro-AutoCount in processing anomalous tree ring images. Full article

During the manufacturing and development of a proof-of-concept prototype of a continuous fiber polyphenylene sulfide (PPS) composite vehicle component, unexpected results were observed in thick laminates of an E-glass-fiber-reinforced PPS matrix, which utilized carbon black as a colorant (GF/PPS+CB). Extensive interlaminar macrocracking, transverse intralaminar microcracking, and micro-/macrovoids were observed in GF/PPS+CB laminates after compression forming. When processed under identical conditions, no micro-/macrocracking or voids were present in GF/PPS laminates and carbon fiber/PPS laminates without carbon black colorant. These observations prompted further investigation into the influence of processing conditions, presence of colorant, mold design (open and closed molds), and geometry (flat and curved) on the development of matrix defects in thick continuous fiber-reinforced PPS laminates. Full article

Naturally fermented black table olives are typically processed in brine with a high NaCl content. Since salt is responsible for several cardiovascular problems, methods are needed to reduce the salt (NaCl) content in the olive flesh. In this study, we investigated the natural fermentation of healthy and damaged black table olives marinated in acidified low-salt brine under slightly pressurized CO₂ (spCO₂) conditions. Tests performed with healthy black table olives of the Leccino cultivar showed the presence of yeasts and the absence of bacteria and molds in the brine during the entire fermentation period. Among the yeasts, Saccharomyces cerevisiae prevailed, especially at the end of the fermentation period. Black table olives damaged by the olive fruit fly Bactrocera oleae (Rossi) were contaminated by various microorganisms, including enterobacteria and lactic acid bacteria, recorded mainly in fruit fly larvae. During fermentation with acidified low-salt brines under spCO₂, enterobacteria did not survive at the beginning of incubation, whereas the lactic acid Leuconostoc mesenteroides identified at the beginning of fermentation disappeared after 2 months of incubation. Among the yeasts that survived during the incubation, S. cerevisiae clearly prevailed. All results confirmed the antimicrobial activity of acidified low-salt brine in the presence of spCO₂. This technology may offer a potentially safer method for production of low-salt olives. Full article

This study quantifies the mechanical behavior of 10–15 mm thick WPC boards compression-molded from post-consumer bottle-cap polyolefins (PP/HDPE, 70/30 wt%) and pine sawdust (0, 10, 20 wt%). Flexural and tensile strength/modulus are determined and application-oriented acceptability assessed for non-structural temporary concrete formwork under ASTM bending and tension protocols. Mechanical performance was evaluated using three-point and four-point bending tests, as well as axial tension. Flexural strengths averaged 17.31, 16.38, and 8.71 MPa for 0, 10, and 20 wt% sawdust (three-points), and 15.23, 13.18, and 9.20 MPa (four-points), with flexural moduli as high as 1.60 GPa (four-points). Tensile strengths averaged 3.60, 3.79, and 3.44 MPa, with tensile elastic moduli of 0.10, 0.33, and 0.36 GPa, respectively. Stress–strain curves showed a nonlinear elastic-brittle response without a defined yield point, followed by fracture, consistent with porous, non-compatibilized WPCs. Variability increased with the sawdust content, reflecting the distribution of filler and matrix-fiber adhesion. Although the properties are inferior to those of conventional building materials, the results are within the application-oriented ranges for non-structural temporary formwork (as established by the reported ASTM tests). UV durability associated with carbon black-pigmented caps is presented as a literature-supported hypothesis for future accelerated aging, rather than as a measured outcome. Overall, the findings demonstrate a circular-economy pathway that converts post-consumer plastics and sawmill waste into WPC panels for sustainable construction. Full article

Various heritage objects can be subjected to various types of biodegradation and biodeterioration. Mold fungi can destroy many types of art—be it monumental art or easel paintings. Tempera paintings on wood are at risk of biodeterioration, since the wide variety of organic and inorganic materials in art objects often provide an optimal habitat for biological colonization, causing aesthetic and structural damage. In this regard, timely identification and characterization of their microbiological destructive potential are critical. The fungi Syncephalastrum sp. STG-160 and Cladosporium sphaerospermum STG-161, isolated from bio-lesion sites of the 16th century icon “Descent into Hell” from State Tretyakov Gallery, Moscow, were identified and characterized morphologically and molecularly in our work. Syncephalastrum sp. was found in an unusual habitat that has not been previously described for this species. To determine the biodegradability of the identified fungi, their cells were inoculated onto mock layers—egg yolk ochre, cobalt green tempera pigments, and watercolor black. The results show that some pigments were more degradable than others. The addition of cobalt green completely inhibited STG-161 growth and significantly deceleratedSTG-160 mycelium development, most likely due to the presence of heavy metal ions in the pigment. Ochre, a frequently used pigment in restoration practice, is the most degradable material for Syncephalastrum sp. STG-160. Combining culture-dependent methods with SEM and fluorescence microscopy allowed us to identify an invisible individual spore of Syncephalastrum sp. STG-160 and a single hypha of Cladosporium sphaerospermum STG-161 directly on the icon’s surface in clean-contaminated zones, potentially allowing their development in cases of adverse temperature and humidity conditions. Therefore, in order to ensure rapid and effective conservation, it is crucial to assess and quantify the presence of biological systems causing damage to the heritage object itself as well as its individual art components. Full article

In the current study, lavender plant (Lavandula angustifolia Mill.) waste, as obtained after the essential oils steam distillation process as well as lignocellulose biomass of two of the most common pine species (Pinus nigra L., Pinus brutia L.), was characterized in terms of chemical composition, moisture, ash content, and calorific value, in order of its potential to be used as feedstock material in pellets production to be assessed, studying different materials ratios. The lavender material was introduced at low percentages (0, 5, 10 and 15% w/w) in the feedstock of pellets, in order to maintain the total ash content of the mixed feedstock as adequately low-lying, ensuring the classification of pellets in qualitative categories of A1, A2 and B (residential uses, ENplus). The resultant lavender–pine mixed syntheses were densified in a multi-mold pelletizing machine and the pellets were characterized with regard to physical, morphological, mechanical, hygroscopic, and thermal characteristics, based on the limits set by the respective ENplus standards as benchmarks. The results demonstrated that although lavender waste has a high content of ash and extractives compared to wood, it can be used in a mixture (<15% lavender percentage) with pure wood material to produce pellets of adequate quality for residential use. The lavender waste presence favored pellets’ mechanical strength, dimensions, hydrophobicity, dimensional stability, bulk density (marginally) and resultant quality of the pellets. Lavender slightly decreased the calorific value of pellets, though without recording a significant adverse impact. The lavender material mixed with black pinewood (at 15%) revealed the best pellets’ feedstock performance. The findings exhibited that lavender lignocellulosic residues are suitable for producing high-performance residential pellets, provided that the lavender content does not exceed 15% of the feedstock. Full article

Phytophthora species are known as water molds and are widespread in rivers and riparian habitats, but the distribution of these oomycetes in coastal and sea ecosystems is not well explored. The present study aims to investigate salt tolerance and potential to survive in marine environment of thirteen Phytophthora species, including P. citricola, P. plurivora, P. pseudosyringae, P. inundata, P. chlamydospora, P. gonapodyides, P. bilorbang, P. lacustris, P. pseudocryptogea, P. syringae, P. polonica, P. honggalleglyana, and P. gallica. The effect of varying concentrations of sodium chloride and the impact of sea water from the Black Sea and the Aegean Sea on mycelial growth, colony type, and formation of different morphological structures by Phytophthora species were studied. The tested isolates belong to different clades of the genus and members of clade 6 stand out with more extensive colony growth on media with elevated salt content compared to the growth on the control medium. A number of Phytophthora isolates produced morphological structures for sexual and/or asexual reproduction under salt stress conditions. The ability of the studied Phytophthora species to exist in marine environment is discussed. Full article

The formation mechanism of black streak defects in hot-rolled steel sheets was investigated to address the influence of the process parameters on the surface quality during the production of 304 stainless steels. Macro-/microstructural characterization revealed that the defect regions contained necessary mold slag components (Ca, Si, Al, Mg, Na, K) which originated from the initial stage of solidification in the mold region of the continuous casting process, indicating obvious slag entrapment during continuous casting. On this basis, a three-dimensional coupled finite-element model for the molten steel flow–thermal characteristics was established to evaluate the effects of typical casting parameters using the determination of the critical slag entrapment velocity as the criterion. Numerical simulations demonstrated that the maximum surface velocity improved from 0.29 m/s to 0.37 m/s with a casting speed increasing from 1.0 m/min to 1.2 m/min, which intensified the meniscus turbulence. However, the increase in the port angle and the depth of the submerged entry nozzle (SEN) effectively reduced the maximum surface velocity to 0.238 m/s and 0.243 m/s, respectively, with a simultaneous improvement in the slag–steel interface temperature. Through MATLAB (version 2023b)-based reverse optimization combined with critical velocity analysis, the optimal mold slag properties were determined to be 2800 kg/m³ for the density, 4.756 × 10⁻⁶ m²/s for the kinematic viscosity, and 0.01 N/m for the interfacial tension. This systematic approach provides theoretical guidance for process optimization and slag design enhancement in industrial production. Full article

The increasing demand for sustainable protein sources highlights Hermetia illucens (Black Soldier Fly, BSF) as a promising alternative. However, microbiological safety remains a key concern. This study investigated the microbial diversity of BSF larvae, comparing two processing methods: (1) boiling followed by drying and (2) drying alone. Microbial diversity was assessed via 16S rRNA sequencing, while bacterial loads were quantified using culture-based methods on samples from a French company. A systematic review complemented this analysis by synthesizing the existing knowledge on BSF microbiota. The rearing conditions varied, with substrate pH ranging from 4.1 to 9.0 and ambient temperatures between 24.6 °C and 42.7 °C. Mesophilic bacteria, spores, and lactic acid bacteria reached up to 8.6, 7.7, and 8.5 log CFU/g in the substrates and larvae, while yeasts, molds, and sulfite-reducing bacteria remained below 4.8 log CFU/g. Boiling reduced most loads below detection thresholds, particularly for yeasts, molds, and ASR. Salmonella, Listeria monocytogenes, Cronobacter sp., and coagulase-positive staphylococci were absent, whereas Clostridium perfringens and Escherichia coli were variably detected. Metabarcoding showed shifts in composition, with Proteobacteria, Bacteroidota, Actinobacteriota, and Firmicutes (Bacillota and Clostridiota) dominating. Process 1 more effectively reduced the bacterial loads, though Bacillus and Clostridium remained. Campylobacter sp. detection in powders raises food safety concerns. Full article

The presence of filamentous fungi with toxigenic ability from the Aspergillus genera is frequently found in maize kernels, and this can lead to decay and mycotoxin contamination of the kernels. In this study, we morphologically and molecularly characterized 45 isolates of Aspergillus section Nigri originating from maize and small grains (wheat, triticale, and spelt) in Serbia. Based on morphological traits, they were classified into two morpho groups. Representative isolates from both morpho groups were further molecularly characterized through sequencing of ITS, CaM and RPB2 genes in order to compare species composition, which could affect specific mycotoxicological risks. Morpho GroupI was molecularly identified as Aspergillus welwitschiae and morpho GroupII as Aspergillus tubingensis. Phylogenetic analysis of the CaM gene revealed that the Serbian Aspergillus welwitschiae isolate belongs to the H8 haplotype, while A. tubingensis isolates clustered into two subclusters. This is the first report of A. tubingensis as the causal agent of black mold of small grains (wheat, triticale and spelt) in Serbia. This distribution underscores the ecological preferences of species within the genus Aspergillus Section Nigri across various agricultural products. It emphasizes the importance of comprehending their occurrence, distribution, aggressiveness and potential for mycotoxin production in food safety assessments. Full article

This study focuses on the development and characterization of biodegradable polymer composites consisting of a polypropylene (PP) matrix, carbon black pigment, and hybrid fillers. The fillers incorporated into these composites consisted of a blend of fibers and particles derived from natural, biodegradable materials, such as flax fibers (FFs) and wood flour (WF) particles. The compositions of polymer material were expressed as PP/FF/WF weight ratios of 100/0/0, 70/5/25, and 70/10/20. The polymer materials were prepared using conventional plastic processing methods like extrusion to produce composite mixtures, followed by melt injection to manufacture the samples needed for characterization. The structural characterization of the polymer materials was conducted using optical microscopy and X-ray diffraction (XRD) analyses, while thermal, mechanical, and dielectric properties were also evaluated. Additionally, their biodegradation behavior under mold exposure was assessed over six months. The results were analyzed comparatively, and the optimal composition was identified as the polymer composite containing the highest flax fiber content, namely PP + 10 wt.% flax fiber + 20 wt.% wood flour. Full article

This study aimed to evaluate the effect of adding shredded black chokeberry (Aronia melanocarpa) pomace on the quality of heat-treated and vacuum-packed pork burgers stored for 14 days at +4 °C. Four burger treatments—Control (BC) and products with 2%, 3.5%, and 5% chokeberry pomace (B2, B3.5, and B5, respectively)—were analyzed for physicochemical properties (thermal loss, shrinkage, content of selected chemical components, pH, color parameters, and shear force) and microbial quality (aerobic mesophilic microorganisms, psychrotrophic bacteria, lactic acid bacteria, Enterobacteriaceae, Pseudomonas spp., Brochothrix thermosphacta, and yeasts and molds). The addition of chokeberry pomace increased (p < 0.05) the thermal loss of pork burgers from 23.5% (BC) to 30.8% (B5) and decreased (p < 0.05) the pH from 6.93 (BC, day 1) to 6.74 (B5, day 14). The introduction of pomace into the pork burgers also significantly (p < 0.05) affected the content of chemical components. However, the nutritional value of pork burgers remained high, with a protein content not lower than 26.68% (BC) and a fat content not exceeding 13.96% (B5). The most affected quality feature of the pork burgers was color. Products B2, B3.5, and B5 exhibited lower L* and b* parameters (p < 0.05) while showing higher a* values. The b* parameter had negative values for products B3.5 and B5 on days 7 and 14. The use of chokeberry pomace did not deteriorate the microbial quality of pork burgers, as indicated by the maximum total count of aerobic mesophilic microorganisms, which reached 4.4 × 10³ cfu/g (B3.5). Moreover, on the final day of storage, moderate antimicrobial properties of chokeberry pomace were observed, with a lower (p < 0.05) number of lactic acid bacteria and Pseudomonas spp. in products B2–B5 compared to BC. The results indicate that incorporating shredded chokeberry pomace into burger-type ground pork products does not present major technological difficulties. However, raw shredded fruit pomace is a perishable microbiological material and requires rapid processing. Further research on the use of chokeberry pomace in burger-type meat products is recommended due to its nutritional value and health-promoting properties. However, this research should include a comprehensive sensory evaluation of the finished product. Full article