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Background: Compounds derived from hydrocarbons are essential for industry and our daily life; however, accidents such as spills or leaks occur regularly, causing severe environmental impact. Therefore, bacteria isolated from an oil well were characterized to assess their potential in the degradation of hydrocarbons under individual and consortium treatments. Soil samples, from a well contaminated with hydrocarbons in Tabasco, Mexico, were collected. The biosurfactant, emulsifying capacity, hemolytic activity, ionic charge, and biofilm formation were analyzed. Results: Most of the isolated strains belong to the genus Pseudomonas according to 16S rDNA sequencing. In general, emulsification percentages greater than 60% in the different substrates evaluated were observed. In addition, these strains can form biofilms, and those selected to integrate the microbial consortia present anionic surfactants. Three strains were selected to evaluate the degradation potential of soil contaminated with hydrocarbons from the same site where the bacteria were isolated in a microcosm. The microbial consortia degraded the contaminated soil more efficiently than the strains were evaluated alone, mainly the three bacteria consortia, with percentages greater than 80%. Conclusions: This study shows that, despite belonging to the same species, bacterial strains' metabolic capacity for the expression of surfactant compounds, emulsifiers, and the formation of biofilms are different. Furthermore, the more structured a community is, the greater the biodegradation process that occurs when bacteria act individually on the substrate. Therefore, this study demonstrates that strains of the same species integrated microbial consortia improve the bioremediation processes of hydrocarbons in contaminated soils. [ABSTRACT FROM AUTHOR]

The assembly of fungal communities on stone materials is mainly influenced by the differential bioreceptivity of such materials and environmental conditions. However, little is known about the role of fungal interactions in the colonization and establishment of fungal species. We analyzed the effects of intra- and interspecific interactions between 11 species of fungi in oligotrophic and copiotrophic media and on limestone coupons. In a previous study, these species were the most frequently isolated in the epilithic biofilms of limestone walls exposed to a subtropical climate. In the culture media, we found a greater frequency of intra- and interspecific inhibitory effects in the oligotrophic medium than in the copiotrophic medium. On the limestone coupons, all fungi were able to establish; however, the colonization success rate varied significantly. Cladosporium cladosporioides had a less extensive colonization in isolation (control) than in dual interactions (coexistence) with other species. Phoma eupyrena exhibited the highest colonization success rate and competitive dominance among all tested species. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses revealed that Pestalotiopsis maculans and Paraconiothyrium sp. produced calcium oxalate crystals during their growth on coupon surfaces, both in isolation and in dual interactions. Our results demonstrate that interactions between abundant fungal species influence the fungal colonization on substrates, the biomineralization and the fungal community assemblage growing in limestone biofilms. [ABSTRACT FROM AUTHOR]

Abstract: Little is known about the dynamics of succession of fungi on limestone exposed in subtropical environments. In this study, the colonization of experimental blocks of compact and porous limestone by a fungal community derived from natural biofilms occurring on Structure X from the archaeological site of Becán (México), was studied using a cultivation-dependent approach after short-term (9 m) exposure in order to provide a preliminary insight of the colonization process under seminatural conditions. Microbial growth seen as the change of colour of stone surfaces to black/dark green was more abundant on the porous limestone. There was a fairly clear difference in microbial colonization between the onset of the experiment and the 6th month for both limestone types, but no significant increase in the colonization of coupons occurred between months 6 and 9. This could be related to the low rainfall expected for this period, corresponding to the dry season. A total of 977 isolates were obtained. From these, 138 sterile fungi were unidentified, 380 could only be assigned to the order Sphaeropsidales; the remaining isolates (459) were grouped into 27 genera and 99 different species. Nearly all detected fungal species belonged to the Ascomycota (90 %). Rare taxa (species represented by one to three isolates) included the recently described genus Elasticomyces, several species of genera Hyalodendron, Monodyctis, Papulospora, Curvularia, and Septoria. Other taxa were Minimedusa and Gliomastix luzulae, which have not been previously described for stone environments. Abundant fungi included several species of the common genera Cladosporium, Alternaria, and Taeniolella typical for a range of habitats. Succession of populations was observed for certain taxa, this shift in the composition of fungal communities was more evident in porous limestone. After 6 m of exposure, species of the genera Scolecobasidium, Hyalodendron, and Taeniolella were predominant, while after 9 m, the predominant species belonged to the genera Curvularia and Alternaria, particularly on porous stone. These results suggest that Curvularia and Alternaria replaced other fungi, due to a higher tolerance towards low levels of available water during the dry season. Higher levels of water within the porous stone, keep longer periods of microbial activity, minimizing the impact of desiccation. This study contributes to understand the diversity of fungal communities in stone surfaces in subtropical settings and the dynamics of colonization on limestone. [Copyright &y& Elsevier]

The widespread use of antibiotics has increased their presence in wastewater, largely due to inadequate removal by conventional treatment methods. This highlights a critical need for effective degradation strategies to mitigate environmental and public health risks. This study reports the photocatalytic degradation of amoxicillin (AMX) using calcium zinc hydroxide dihydrate [CaZn 2 (OH) 6 ·2H 2 O] (CZ) and zinc oxide (ZnO) nanoparticles (NPs) synthesized by different routes. X-ray diffraction results confirmed the formation of CZ NPs with an 81–95% crystalline phase, while ZnO NPs present a single crystalline phase. The photolysis of AMX under UV-A light (365 nm) was strongly pH-dependent, with degradation rates of 34.7, 5.7, and 4.2% observed at pH 3, 5, and 13, respectively. Maximum adsorption occurred at pH 3, with ZnO achieving 63–83.2% AMX removal and 23.5–47.1% in the case of CZ. The highest overall AMX removal was observed at pH 3, where adsorption dominated the photocatalytic process for both CZ and ZnO. At pH 5 and 13, degradation was primarily driven by photocatalysis in CZ materials, particularly CZ-HT and CZ-SG, while adsorption remained predominant in ZnO. Proton nuclear magnetic resonance analysis indicates benzene ring cleavage in AMX photodegraded by CZ materials. Furthermore, the residues of photodegraded AMX by CZ materials lost antimicrobial activity against Gram-positive and Gram-negative bacteria. Additionally, the reuse of NPs over four cycles maintained consistent degradation performance, highlighting their potential for repeated applications. The comparative analysis of CZ and ZnO NPs superior photocatalytic efficiency of CZ in degrading AMX. This efficiency, along with its potential for repeated use, establish CZ as a promising material for environmental applications aimed at reducing antibiotic contamination and the associated risks of resistance development. [Display omitted] • CaZn 2 (OH) 6 ·2H 2 O (CZ) achieves high photocatalytic degradation of amoxicillin. • ZnO NPs show no photocatalytic activity, although it adsorbs amoxicillin. • Complete loss of antimicrobial activity in the amoxicillin residuals was confirmed. • CZ and ZnO maintain photocatalytic or adsorption activity over multiple reuse cycles. • The removal of amoxicillin were confirmed by 1H RMN spectra. [ABSTRACT FROM AUTHOR]

Recent research has increasingly focused on synthesizing nanoparticles (NPs) through various methods to determine how these processes influence their characteristics, and consequently, their biological activity. Calcium zinc hydroxide dihydrate (CaZn2(OH)6·2H2O) nanoparticles, designates as CZ, were obtained via sol–gel (CZ-SG), hydrothermal (CZ-HT), and microwave (CZ-MW) methods, and their properties were characterized using XRD, SEM, TEM, and BET analyses. The different synthesis revealed distinct CZ nanoparticle attributes, including variations in crystallite sizes (72 nm for CZ-SG, 65 nm for CZ-HT and CZ-MW) and morphologies (fibrous for CZ-HT and spherical agglomerates for CZ-SG and CZ-MW). Surface area analysis showed low values across all synthesis methods, with CZ-HT exhibiting the best surface area (8.154 m2/g). The investigation also explored how these synthesis routes influence antifungal efficacy against fourteen fungal strains associated with the biodeterioration of limestone cultural heritage structures. Our results highlight the notable antifungal activity of CZ-NPs, particularly those synthesized via the CZ-HT method, which demonstrated the most effective antifungal action as evidenced by the lowest minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). This effectiveness is attributed to the unique fibrous morphology, which proves to be highly inhibitory to fungal cell proliferation. These findings not only advance our understanding of CZ NPs-mediated antifungal mechanisms but also open a new effort for the development of effective preservation strategies for cultural heritage conservation. [ABSTRACT FROM AUTHOR]

Fungal growth on construction materials in tropical climates can degrade aesthetics and manifestations on modern and historical sick buildings, affecting the health of their inhabitants. This study synthesized ZnO nanoparticles with enhanced antifungal properties using a precipitation method. Different concentrations (25%, 50%, and 100%) of Eichhornia crassipes aqueous extract were used with Zn(NO3)2·6H2O as the precursor to evaluate their spectroscopic, morphological, textural, and antifungal properties. X-ray diffraction confirmed the hexagonal wurtzite phase of ZnO with crystallite sizes up to 20 nm. Fourier-transform infrared spectroscopy identified absorption bands at 426, 503, and 567 cm−1 for ZnO-100, ZnO-50, and ZnO-25, respectively. Nitrogen physisorption indicated a type II isotherm with macropores and a fractal dimension coefficient near 2 across all concentrations. Polydispersity index analysis showed that ZnO-50 had a higher PDI, indicating a broader size distribution, while ZnO-25 and ZnO-100 exhibited lower PDI values, reflecting uniform and monodisperse particle sizes. FESEM observations revealed semi-spherical ZnO morphologies prone to agglomeration, particularly in ZnO-25. Antifungal tests highlighted ZnO-25 as the most effective, especially against Phoma sp. with an MFC/MIC ratio of 78 µg/mL. Poisoned plate assays demonstrated over 50% inhibition at 312 µg/mL for all tested fungi, outperforming commercial antifungals. The results indicate that ZnO NPs synthesized using E. crassipes extract effectively inhibit fungal growth on construction materials. This procedure offers a practical approach to improving the durability of building aesthetics and may contribute to reducing the health risks associated with exposure to fungal compounds. [ABSTRACT FROM AUTHOR]

Avocado (Persea americana) and papaya (Carica papaya) are tropical fruits with high international demand. However, these commercially important crops are affected by the fungus Colletotrichum gloeosporioides, which causes anthracnose and results in significant economic losses. The antifungal activity of metal oxide nanomaterials (zinc oxide (ZnO), magnesium oxide (MgO), and ZnO:MgO and ZnO:Mg(OH)2 composites) prepared under different conditions of synthesis was evaluated against strains of C. gloeosporioides obtained from papaya and avocado. All nanoparticles (NPs) at the tested concentrations significantly inhibited the germination of conidia and caused structural damage to the fungal cells. According to the radial growth test, the fungal strain obtained from avocado was more susceptible to the NPs than the strain obtained from papaya. The effect of the tested NPs on the fungal strains confirmed that these NPs could be used as strong antifungal agents against C. gloeosporioides to control anthracnose in tropical fruits. [ABSTRACT FROM AUTHOR]

The humid tropical environment provides an ideal place for developing a high diversity of plants; this is why it is an interesting site for the enzymatic bioprospecting of fungi that are responsible for the recycling of organic matter in an efficient and accelerated way and whose enzymes could have multiple biotechnological applications. For this study, 1250 isolates of macroscopic and microscopic fungal morphotypes were collected from soil, leaf litter, and wood. One hundred and fifty strains (50 from each source) were selected for the enzymatic screening. From the first phase, 51 strains with positive activity for laccase, protease, amylase, xylanase, and lipase enzymes were evaluated, of which 20 were isolated from leaf litter, 18 from the soil, and 13 from wood. The 10 best strains were selected for the enzymatic quantification, considering the potency index and the production of at least two enzymes. High laccase activity was detected for Trametes villosa FE35 and Marasmius sp. CE25 (1179 and 710.66 U/mg, respectively), while Daedalea flavida PE47 showed laccase (521.85 U/mg) and protease activities (80.66 U/mg). Fusarium spp. PH79 and FS400 strains had amylase (14.0 U/mg, 49.23 U/mg) and xylanase activities (40.05 U/mg, 36.03 U/mg) respectively. These results confirm the enzymatic potential of fungi that inhabit little-explored tropical rainforests with applications in industry. [ABSTRACT FROM AUTHOR]

A series of poly[2-(dimethylamino)ethyl methacrylate]s (PDMAEMAs) of different molar mass were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. The polymers were subsequently treated with two different alkyl halides (1-iodobutane (BuI) and iodomethane (MeI)) to obtain a library of 21 PDMAEMAs with different degree of quaternization (DQ). This is the first report where the antifungal activity of these polymers is assessed for different fungi relevant in biomineralization and aesthetic biodeterioration of stone surfaces. The antifungal activity was assessed with the minimum inhibitory concentration (MIC), the minimum fungicidal concentration (MFC) and the mycelia growth inhibition in plate for the most promising materials. The obtained results demonstrated that all evaluated polymers possess certain level of antifungal activity against the evaluated fungi (even unquaternized PDMAEMAs). However, polymers of low molar mass (series III) revealed predominantly fungicidal activity at low values of MFC (from 2500 to 9.7 μg mL−1). Unexpectedly, the performed mycelia growth inhibition tests showed that the DQ has a less significant effect on the antifungal properties of the polymers than the polymer molar mass. Hence, the antifungal activity of these polymers may depend to a great extent on the physiological and morphological characteristics of the fungi, wherein the best antifungal activity was observed in III-M2, III-B1 and III-B2. It is worth mentioning that this detailed screening contributes to a better understanding of PDMAEMA-based composites that can be utilized in the development and optimization of low-cost and accessible antimicrobial protective coatings for petrous surfaces in cultural heritage monuments or modern buildings. [Display omitted] • Antifungal activity of PDMAEMA derivatives against relevant biodeterioration fungi. • Most of PDMAEMAs were fungicide and some fungistatic as well. • A better fungicide performance was observed for PDMAEMAs of low molar mass. • PDMAEMAs could be applied as coatings for conservation of petrous surfaces. [ABSTRACT FROM AUTHOR]

• The photocatalytic activity improves as the concentration of Ca(OH) 2 increases in mixtures with CZ. • The addition of low concentration of Ca(OH) 2 to CaZn 2 (OH) 6 •2H 2 O improves the fungicidal action. • The synergy of CZ and Ca(OH) 2 can consolidate the rock and inhibit antifungal growth. • Stability of CZ in solution improves with low proportions of Ca(OH) 2. The antifungal and photocatalytic activity of mixed compounds of double hydroxide [CaZn 2 (OH) 6 •2H 2 O] with portlandite [Ca(OH) 2 ] synthesized via sol-gel were evaluated. The compound was tested by in vitro assay to determine its antifungal activity using the agar diffusion and broth microdilution assays, applied to the fungal models: Aspergillus niger and Penicillium oxalicum. Also, these compounds were characterized by X-ray diffraction, infrared spectroscopy, dynamic light scattering, and its morphological structure was identified by HR-SEM and TEM-SAED which shows agglomerated particles formed by nanoparticle sizes between 100−500 nm, which are correlated whit hydrodynamic radio around 155 nm. Additionally, in the relation of microbiological assays, the outstanding minimum inhibitory concentration of unmixed calcium zincate hydroxide dihydrate (CZ) correspond to 156 μg/mL, however, when is mixed with 10 % of Ca(OH) 2 diminishes up to 78 μg/mL, indistinctively of the evaluated fungus. Likewise, a photocatalytic degradation test was carried out with methylene blue dye as a model organic pollutant, reaching an efficiency of ∼92 %. Our results suggest that low concentrations of Ca(OH) 2 improve the antifungal activity of CZ, without altering the solution stability, the photocatalytic and chemical properties of the compounds. Therefore, the compatibility with the limestone of both materials can be proposed as an excellent product to avoid fungal biodeterioration. [ABSTRACT FROM AUTHOR]