Search Results (292)

Ornamental fountains in the Alhambra and Generalife (Granada, Spain) constitute complex socio-ecological systems where water, stone, and biological communities interact, making them highly vulnerable to biodeterioration caused by phototrophic microorganisms such as cyanobacteria, green algae, and diatoms. Conventional chemical biocides, although widely applied, present significant drawbacks including toxicity, material degradation, ecological imbalance, and limited long-term effectiveness. In this context, this study evaluated the potential of algicidal bacteria as a sustainable alternative for controlling phototrophic growth in heritage environments. Water samples from eight ornamental fountains were analyzed using 16S ribosomal RNA (16S rRNA) gene sequencing to characterize bacterial communities and identify taxa previously reported with algicidal activity. Statistical analyses were conducted to assess relationships between microbial community structure and biofilm development. In parallel, functional screening assays using filtered fountain waters against Chlorella vulgaris were performed to evaluate intrinsic inhibitory capacity. The most active sample was selected for bacterial isolation and further validation through co-culture assays, cell density measurements, and pulse-amplitude-modulated (PAM) fluorometry. A total of 18 genera with reported algicidal capacity were detected, representing a substantial fraction of the microbiome across all samples. However, no significant association was found between these taxonomic metrics and biofilm development, highlighting a decoupling between taxonomic composition and functional activity. The most active isolate, identified as Stenotrophomonas maltophilia strain LIG25, caused a rapid decline in photosynthetic efficiency and achieved more than 98% inhibition of algal growth. These findings demonstrate that ornamental fountain microbiomes represent a reservoir of native biocontrol agents and support the development of eco-friendly strategies for cultural heritage conservation. Full article

Phi Man Long Long Rak Cave, located in Mae Hong Son Province, northern Thailand, is a prehistoric burial site containing ancient wooden coffins that have undergone biodeterioration, likely due to fungal activity. Both culture-dependent and culture-independent approaches were employed to characterize fungal communities and assess their roles in wood degradation. Culture-dependent analysis identified five Aspergillus isolates from the wooden coffins, most of which produced cellulolytic and hemicellulolytic enzymes; some isolates also produced organic acids, indicating significant degradative potential. Culture-independent analysis revealed a community dominated by Aspergillus, together with additional taxa such as Penicillium and Ceriporia that were not detected by cultivation, highlighting greater community diversity and demonstrating the complementarity of the two methods. Functional prediction indicated a predominance of saprotrophic fungi. The presence of shared dominant taxa between soil and coffin-associated substrates suggests ecological connectivity at the soil–coffin interface, although the direction of dispersal cannot be determined from the present data. All tested fungicides inhibited fungal growth, with the highest efficacy observed in the formulation containing the highest proportion of active components. Taken together, these findings provide insights into fungal biodeterioration processes and inform conservation strategies. Full article

Synthetic polymers are widely used in stone conservation, yet their long-term biological stability remains insufficiently evaluated. This study investigates the microbial susceptibility of three commonly used acrylic consolidants, Paraloid B-72, B-66, and B-44, applied to deteriorated limestone. Bacteria, fungi, and actinomycetes were isolated from a deteriorated limestone false door and screened for acid production. From each microbial group, only the strong acid-producing isolates were selected for further investigation, including evaluation of their ability to utilize the three Paraloid resins as sole carbon sources and their deterioration potential on limestone cubes before and after consolidation. Deterioration was assessed by weight loss, compressive strength testing, stereomicroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). All selected strong acid-producing isolates demonstrated the ability to grow on the tested polymers, confirming their biodegradation potential. Mixed microbial cultures caused greater weight loss and compressive strength reduction than single isolates, attributed to synergistic metabolic interactions. Among the consolidants, Paraloid B-72 showed the highest susceptibility to microbial attack, while Paraloid B-66 exhibited comparatively greater resistance, attributed to the steric hindrance of its isobutyl side groups and higher surface hydrophobicity. FTIR and XRD analyses confirmed ester bond hydrolysis, progressive gypsum formation, and structural alteration of the limestone substrate. These findings demonstrate that acrylic consolidants commonly used in stone conservation are not biologically inert and may actively contribute to biodeterioration under microbial colonization, highlighting the need for developing bio-resistant conservation materials. Full article

Dajue Temple, a representative ancient architectural heritage in North China, houses numerous lacquered wooden components of exceptional historical and artistic value. Prolonged environmental exposure causes severe dark discoloration and black spotting on lacquer surfaces, threatening their structural integrity. This first investigation into the damage identifies the spots as microbial in origin, with Cladosporium spp. as the primary agent driving deterioration and possessing wood-degrading capabilities. Antifungal tests show that thymol, clove essential oil, and nano-silver gel are all effective inhibitors. We proposed targeted, relic-friendly microbial control strategies tailored for ancient lacquered wooden components. These findings provided scientific guidance for the sustainable conservation and restoration of lacquered architectural elements in historic temples and comparable cultural heritage sites. In future work, environmental monitoring and the biocides’ compatibility should be involved, which will help to clarify microbe–environment interactions, enable early warning of biodeterioration risks and explore the wood-friendly biocides. Full article

The accumulation of polyethylene (PE) in aquatic ecosystems represents a significant environmental challenge due to the polymer’s high molecular weight and chemical stability. This study investigates the biodegradation potential of Hafnia paralvei UUNT_MP29, a bacterial strain isolated from the gut of common carp (Cyprinus carpio), for low-density polyethylene (LDPE). Initial screening on LDPE-emulsified agar confirmed extracellular enzymatic activity through the formation of distinct clear zones. Quantitative analysis showed a cumulative mass loss of 24.10% by Day 16, with the most intensive degradation occurring between Days 4 and 8, which closely correlated with maximum bacterial count (CFU/mL). Kinetic modeling indicated that the degradation followed a first-order rate law (R² = 0.9269), with a rate constant (k) of 0.2991 days⁻¹ and a remarkably short half-life (t_1/2) of 2.32 days. Structural characterization via FTIR spectroscopy demonstrated oxidative transformation, evidenced by a reduction in sp³ C-H stretching and the emergence of C-O/C-O-C functional groups. SEM micrographs further confirmed extensive bio-deterioration, including surface pitting and macroscale erosion. Thermal analysis (TGA/DTG) supported these findings, showing a significant 10.95 °C decrease in the maximum degradation temperature (T_max), indicating a reduction in polymer chain length. These results suggest that H. paralvei UUNT_MP29 is a highly efficient agent for the rapid breakdown of polyethylene and highlight the potential of aquatic gut microbiota as reservoirs for plastic-degrading biotechnologies. Full article

Water-miscible metalworking fluids are widely used in industrial processes. Despite the fact that they typically contain biocides, they are almost always colonized by microorganisms, which degrade different components of the liquid, may clog machines due to biofilm formation, and might pose a health risk to workers. In this study, samples from four metalworking machines operated with the same metalworking concentrate were analyzed with respect to microbial growth. Twenty-seven bacterial species and one fungus were identified. From these, twenty species were not observed before as colonizers of metalworking fluids. Growth of microorganisms, putative contamination sources, metabolic pathways involved in biodegradation, and resulting health risks are analyzed and discussed in this study. Full article

The Jinshanling Great Wall is an important part of the Ming Great Wall, the most important material cultural heritage of China, and is currently facing a significant threat of microbial degradation due to the widespread biological weathering of open-air masonry buildings. This study focuses on the Qilin Screen Wall and Text Brick Wall of the Jinshanling Great Wall, utilizing scanning electron microscopy (SEM) and metabarcoding analyses to reveal the diverse microbial communities coexisting on the masonry surfaces, including various lichens, molds, and bacteria. Twelve fungal strains were successfully isolated. The antimicrobial experiment results indicated that 0.6% isothiazolinone-based antimicrobial BC01, 50 mg/mL carvacrol and 50 mg/mL thymol exhibited a certain degree of antimicrobial activity against these strains. Overall, this study has laid a solid foundation for microbial control of the masonry Great Wall through in-depth analysis of microbial community structure and screening of highly effective antimicrobials. Full article

Plastic pollution is a global environmental crisis, and microbial degradation represents a promising remediation strategy. While bacteria have been widely studied, yeasts offer unique advantages for plastic degradation due to their metabolic versatility, stress tolerance, and enzymatic capabilities. However, plastic degradative yeasts have not been reviewed comprehensively. Although several yeasts capable of degrading polyethylene terephthalate (PET) or polyethylene (PE) have been reported (e.g., Moesziomyces antarcticus, Candida tropicalis, Yarrowia lipolytica and Rhodotorula mucilaginosa), degraders of other plastic types are less studied. Although some yeasts can assimilate carbon from plastics, the diversity of yeasts capable of participating in plastic mineralization remains vastly underexplored. In recent years, yeast cell surface display systems for bacterial PETase and fungal cutinase have been developed, demonstrating promising PET degradation efficiency. However, PETase is feedback-inhibited by the intermediate product mono(2-hydroxyethyl)terephthalate (MHET). Systems synergizing PETase with MHETase have shown superior stability during long-term PET degradation and enable large-scale depolymerization of PET waste. For high-crystallinity PET, fungal hydrophobins can be used to modify the surface hydrophobicity of PETase-displaying yeast cells, facilitating their attachment to hydrophobic PET surfaces and ultimately enhancing the degradation efficiency of the whole-cell biocatalyst. Limitations of current research and future directions are also discussed. Full article

Stone heritage deteriorates through physical, chemical, and biological processes driven by water, climate, and microbial colonization. Multifunctional polymeric coatings combining hydrophobic and antimicrobial moieties have emerged as a promising conservation strategy, yet a substantial gap remains between laboratory innovation and real-world performance. This review critically examines advances from 2021 to 2026, covering wetting theory, antimicrobial mechanisms, and material architectures, including molecularly integrated systems, Sol–Gel hybrids, nanocomposites, and layered systems. Long-term studies on the Aurelian Walls in Rome and stone in Reims show that biocidal efficacy typically declines within one to two years despite the chemical persistence of the coatings. In parallel, hydrophobic performance often deteriorates over time due to UV exposure, particulate deposition, and surface chemical changes, leading to increased wettability and reduced protective efficiency. Substrate porosity governs durability and visual compatibility (ΔE* < 5 threshold), while treatments can reshape microbial communities, favoring stress-tolerant meristematic fungi. Regulatory pressure on fluorinated compounds drives the development of more sustainable alternatives. Emerging directions include stimuli-responsive systems, self-healing materials, slippery interfaces, and precision polymer architectures. However, future progress will depend on tailoring formulations to major lithotypes, improving compatibility with porous substrates, and validating performance through standardized accelerated aging and multi-year field trials. Bridging laboratory design with environmental exposure data and conservation practice will be essential for achieving durable and culturally acceptable protection strategies. Full article

Microorganisms such as Arthrobacter spp. are important agents of biodeterioration in cultural heritage (CH) environments, causing orange–yellow chromatic alterations and contributing to substrate degradation. This study evaluates two complementary tools for the rapid detection and mitigation of Arthrobacter spp.: a newly designed genus-specific RNA–fluorescence in situ hybridisation (FISH) probe (Art1420-Cy3) and an antimicrobial peptide fraction produced by Saccharomyces cerevisiae ISA 1028. The RNA-FISH probe Art1420-Cy3 showed high specificity and sensitivity, labelling 80–85% of Arthrobacter cells at 10% (v/v) formamide and enabling their detection by epifluorescence microscopy and flow cytometry. The peptide fraction exhibited pronounced bactericidal activity, reducing Arthrobacter culturability from ~10⁸ to ~10¹ CFU/mL within 48 h, while also inhibiting other biodeteriogenic microorganisms. Overall, these findings outline the basis for an integrated and CH-compatible approach that combines precise Arthrobacter cells detection and identification with targeted, biologically derived control. Although further validation using real heritage samples and application protocols specifically tailored to sensitive materials is required, this strategy shows strong potential as a sustainable alternative to conventional chemical biocides and as a practical framework for detecting and mitigating pigment-producing biodeteriogens in CH and other vulnerable environments. Full article

As an important biomass material, bamboo is susceptible to fungal infection during use, leading to severe deterioration. The white-rot fungus Schizophyllum commune is one of the world’s most widely distributed fungi, which preferentially colonizes dead or senescent bamboo tissues. However, the mechanism of the influence of the S. commune infection on the mechanical and chemical properties of bamboo remains unexplored. This research systematically examined the temporal effects (0, 30, 60, and 90 days) of S. commune QP33 infection on bamboo’s mechanical properties and chemical composition using various characterization methods. Results showed that S. commune QP33 secreted key lignin-modifying enzymes (laccase and lignin peroxidase) and hemicellulases (xylanase). Mass loss of bamboo increased progressively with infection time, reaching 13.33% after 90 days. Decayed bamboo showed distinct mechanical deterioration patterns, including a sharp initial drop in bending strength and a continuous decline in tensile strength. Microstructural and chemical analyses revealed that the fungus preferentially degraded lignin and hemicellulose. This selective degradation led to cell wall delamination and pore formation, ultimately causing the observed macroscopic mechanical deterioration. Our study provides critical insights into the biodeterioration mechanism of bamboo by S. commune and offers valuable guidance for bamboo preservation and high-value utilization. Full article

Filamentous fungi are among the most significant biological agents responsible for the biodeterioration of organic cultural heritage materials preserved in archives, libraries, and museums. Cellulose-based substrates—such as paper, papyri, and plant-derived textiles—as well as protein-based materials, including parchment and leather, provide favourable conditions for fungal colonization due to their chemical composition and hygroscopic behaviour. Once activated, fungi contribute to deterioration through a combination of mechanical penetration and biochemical processes, including the secretion of hydrolytic enzymes, organic acids, and pigmented metabolites, which progressively compromise the structural integrity and visual appearance of heritage objects. This review aims to critically synthesize current knowledge on the mechanisms of fungal biodeterioration affecting organic heritage materials, with particular attention to material-specific vulnerabilities, indoor environmental drivers, and implications for preventive conservation. Recent advances in fungal ecology have highlighted the presence of xerophilic and extremotolerant taxa capable of persisting under conditions traditionally considered unfavourable for microbial growth, posing new challenges for conservation management. Rather than attributing biodeterioration directly to global climate change, this review explicitly emphasizes the role of indirect and building-mediated climate-related stressors—such as increased frequency of moisture intrusion events, infrastructure vulnerability, and microclimatic instability within buildings—in shaping fungal risk in indoor heritage environments. The integration of environmental monitoring, microbiological diagnostics, and predictive risk-assessment tools emerges as a key strategy for early detection and mitigation. By consolidating interdisciplinary evidence from microbiology, materials science, and heritage conservation, this work underscores the need to shift from reactive restoration toward anticipatory, risk-based preventive approaches to ensure the long-term preservation of organic cultural heritage materials. Full article

Synthetic plastics are polymers that are largely produced worldwide, impacting ecosystems and human health. Microplastics are produced from fragmentation and degradation of larger plastics, as a consequence of environmental factors. Low-density polyethylene (LDPE) and polypropylene (PP) are plastic polymers acting as environmental hazards. Challenges in effective plastic waste management include sustainable and environmentally responsible approaches like microbial degradation. In this work, a shotgun metagenomic approach has been applied to analyze the response of the microorganisms living on plastic surfaces (plastispheres) of LDPE and PP to biodeterioration of these plastics (BioProject-NCBI, PRJNA1378224). Low-density polyethylene and polypropylene materials were collected from a waste landfill of intensive greenhouse agriculture. A further functional analysis supported putative roles of enzymes that could be involved in the initial steps of biodeterioration of LDPE and PP, including sarcosine oxidases; bromo- and chloro-peroxidases; cytochrome P450 and alkane monooxygenases; and multicopper oxidases. A CheckM analysis of genes that code for these oxidative enzymes revealed that they were mainly from the bacterial Phyllobacterium genus (Rhizobiaceae family) and, in less abundance, from the archaeon Methanoculleus genus (Methanoculleaceae family). This study supports putative roles of sarcosine oxidases and bromoperoxidases, and other relevant enzymes, in bacterial and archaeal LDPE and PP biodeterioration, highlighting the genomic potential of the microbiomes under study in biodeterioration of these synthetic plastics. Full article

Two commercial adhesive tape strips (Fungi-Tape^TM and Filmoplast^® P) and a polyvinyl alcohol–borax (PVA-B) gel were tested as novel physical cleaning alternatives to micro-aspiration for removing visible fungal colonisation from a cotton canvas. In addition, clove essential oil (CEO) and Cyrene™ were incorporated in the PVA-B gel for testing the potential of each to improve fungal cleaning. For the trials, canvas mock-ups were separately inoculated with two fungal species identified as Penicillium chrysogenum and Aspergillus westerdijkiae. Removal of fungi and related impacts were evaluated by DOM, FESEM, ATR-FTIR and ImageJ software. Inhibition of fungal spores and residual growth were assessed by in vitro growth tests and CLSM. Removal of A. westerdijkiae was more effective than removal of P. chrysogenum, especially for dense coverage. Both tape strips removed slightly more fungus than micro-aspiration, except for dense coverage of P. chrysogenum. The PVA-B gel, both with and without CEO or Cyrene™, yielded the best (similar) results, removing the fungal material found on the surface and subsurface of canvas without damaging the canvas fibres. Although further testing is required, the antifungal activity of PVA-B gel+ Cyrene™ seems comparable to that of PVA-B gel+ CEO, the former being especially effective against A. westerdijkiae. Full article

The presence of lithobionts has historically been associated with biodeterioration, posing significant challenges to the conservation of culturally and historically significant stone heritage. This perception stems from abundant evidence of their role in biogeophysical processes, such as mechanical disruption of stone structures, and biogeochemical processes, which chemically alter stone composition through metabolic activity. These processes, while integral to natural systems, often accelerate the weathering and deterioration of heritage materials. Coupled with the aesthetic impact of lithobiont growth, frequently resulting in discoloration or obscuring of intricate details, such effects have justified the widespread removal of these organisms from heritage surfaces. However, recent research has revealed a far more nuanced picture. These communities can enhance biodiversity, contribute to the perceived authenticity of aged monuments, and, in some cases, form a biological layer that shields stone from pollutants and weathering forces. Moreover, developments in biomediated conservation approaches, such as biocementation and biocleaning, highlight their potential as sustainable allies in preservation. This dual role of lithobionts—both as friends and foes in preservation—is central to this review. This review focuses on how these organisms—with a particular emphasis on fungi, often perceived as enemies of conservation—may also serve as unexpected partners in safeguarding our stone heritage, emphasizing the need for case-by-case evaluation of active communities and their environmental context. Full article