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• Effects of pyrolysis conditions on the biochar properties of three different organic waste. • Biochars from rice husk, olive pit and olive prunings were produced and characterized. • C and N content mainly depended on biochar feedstock. • Aryl-C, alkyl–C and hydrophobicity were predominately influenced by residence time. • Feedstock and pyrolysis temperature conditioned water holding capacity and ash content. Biochar is a pyrogenous organic material resulting from the pyrolysis of organic residues, which is attracting the interest from researchers and farmers for its potential to sequester carbon and its use as soil ameliorant. Pyrolysis conditions and feedstock determine the properties of the biochars produced. In order to understand the relationship between these variables we analysed in detail the physical, chemical and surface characteristics of biochars produced from three contrasting agronomic residues abundantly generated in South Spain, such as rice husk (RH), olive pit (OP) and pruning remains of olive trees (mainly composed of olive branches and leaves; OB), using a temperature range from 350 to 600 °C and residence times from 0.5 to 4 h. High pyrolysis temperature (600 °C) and time resulted in the greatest pH and C content in the biochars. In general, elemental composition and ash content were dependent on the type of organic waste used as feedstock. 13C Nuclear Magnetic Resonance Spectroscopy and thermal (TG-DSC) analyses showed that temperatures ≥500 °C are needed to achieve a high degree of aromatization of the chars. Micro-computed tomography and field emission scanning electron microscopy revealed that the structure of RH was preserved during the pyrolysis process, favouring a greater porosity for these biochars. These data are very useful for the production of stable biochars obtained from residual biomass, maximising the value of residual biomass resources. These biochars show physical and chemical properties, such as adequate pH, high water retention capacity or high porosity, of interest for their use as soil amendments. [ABSTRACT FROM AUTHOR]

This work presents the first review on biodiversity, biodeterioration and bioreceptivity of architectural ceramics. Literature dating from 1972 to 2014 was compiled and analysed in order to summarise the current knowledge and to facilitate a better understanding of the subject. Data regarding biodiversity found on architectural ceramic materials was described for three typologies: bricks, roofing tiles and glazed wall tiles. A vast biodiversity has been identified on these ceramic materials, from bacteria to more complex organisms, such as plants. Bricks were the most studied substrate, while literature on glazed wall tiles was scarce. The highest biodiversity was found on bricks, may be due to the fact that this was the most studied typology. Several works regarding the colonization of ceramic roofing tiles by lichens were found in the literature, which led us to realise that this is a topic that arouses the attention of several researchers. Photoautotrophic microorganisms found on glaze wall tiles represented a considerable biodiversity in this ceramic typology, with many genera in common with those identified on bricks and roofing tiles. Nevertheless, in the searched literature, different methods had been used to identify and characterize the organisms. This made the comparison of the global biodiversity found on these substrates difficult. Architectural ceramic materials exposed to outdoor conditions are often affected by biodeterioration. This worldwide problem can cause aesthetical, physical and chemical damages on ceramic materials. The distinct biodeterioration processes occurring on the different substrates found on architectural ceramic materials are explained in detail. The relationship between the ceramic intrinsic properties and bioreceptivity was discussed. Porosity and surface roughness seemed to play a major role in bioreceptivity to colonization. Ceramic microstructure has a strong influence on the resistance to biodeterioration. Finally, the authors come to the conclusion that there are many gaps in the knowledge, especially concerning glazed ceramics, and thus, further research was proposed. [ABSTRACT FROM AUTHOR]

Abstract: Three actinobacteria strains isolated from a green biofilm covering the biodeteriorated interior walls of Vilar de Frades Church (Portugal) were studied using a polyphasic approach. The three strains were aerobic, non-spore forming and Gram-positive. Phylogenetically, the most closely related described species was Rubrobacter radiotolerans (94.2–94.3% and 81.9–82.5% similarities for the 16S rRNA and rpoB gene sequences, respectively). The fatty acid profile was dominated by anteiso-C17:1 ω9c, and MK-8 was the only menaquinone present. These data clearly showed that the three strains could represent a new species, for which we propose the name Rubrobacter bracarensis sp. nov., with strain VF70612_S1T (=CECT 7924=DSMZ 24908) as the type strain. [Copyright &y& Elsevier]

Biochar application to soils has become a focus of research during the last decade due to its high potential for C sequestration. Nevertheless, there is no exhaustive information on the long-term effects of biochar application in soils contaminated with trace elements. In this work, a 2-year field experiment was conducted comprising the application of different types of biochar to acidic and moderately acidic soils with high concentrations of As, Cu, Pb, Ba and Zn. In addition, representative samples of each biochar were buried in permeable bags that allowed the flow of water and microorganisms but not their physical interaction with soil aggregates. The biochars significantly adsorbed trace elements from polluted soils. However, given the high total concentration of these persistent trace elements in the soils, the application of biochars did not succeed in reducing the concentration of available metals (CaCl 2 extractable fraction). After 2 years of ageing under field conditions, some degradation of the biochars from olive pit, rice husk and wood were observed. This study provides novel information concerning the biochar alterations during ageing in polluted soils, as the decrease of aryl C signal observed by 13C nuclear magnetic resonance (NMR) spectroscopy and the presence of O-containing groups shown by Fourier Transform mid-Infrared Spectroscopy (FT-IR) in aged biochar which enhanced trace elements adsorption. Scanning electron microscopy (SEM) revealed slight changes on surface morphology of aged biochar particles. [Display omitted] • Metal immobilisation by biochar was determined by burying and used as amendment. • Field-aged biochars exhibited significant adsorption of trace element contents. • > 8 t ha−1 of biochar are needed to reduce soil-available trace element contents. • Biochar amendment increased total C and aryl C in soils at 0–10 cm depth. • Biochar aromatic C was degraded under 2-year field ageing. [ABSTRACT FROM AUTHOR]

Application of biochar has been widely suggested as a remediation tool for trace element-polluted soils, but the impact of biochar on microbial communities and on native plants remain largely unknown. To overcome this knowledge gap, biochar produced from rice husk and olive pit were applied at a rate of 8 t ha−1 into a soil with two contrasting levels of trace elements (high and moderate) to study their effects on soil microbial community composition, vegetation cover and soil properties after 1, 6, 12 and 20 months under field conditions. Differences in bacterial community composition were studied using the Illumina Miseq technology of the 16S rRNA gene. Although variations in soil properties and ecological function were seasonal and soil-type dependent, biochar application enhanced soil properties and vegetation cover in the moderately polluted soil (MPS), and increased microbial diversity as well as vegetation cover in the highly polluted soil (HPS). Enzymatic activities and soil respiration rates were not modified with the application of biochar, but increased total carbon content of soils. The application of biochar from crop residues to trace-element contaminated soils provided environmental benefits, including plant diversity and growth, as well as the increase of bacterial diversity and carbon sequestration. • Biochar was applied in moderately and highly polluted soils under field conditions. • Biochar application increased bacterial and plant diversity in highly polluted soil. • Bacterial diversity slightly changed in moderately polluted soil with biochar. • Soil pH was key factor of bacterial community structure. • Seasonal changes affected microbial community, soil respiration and vegetation. [ABSTRACT FROM AUTHOR]

• The alcobaça monastery currently exhibits an extensive bacterial pink biofilms. • This biodeterioration evidence seems to be associated with salt efflorescences. • The colour is probably due to the production of bacterial pigments. • High-throughput sequencing allowed the identification of pink-pigmented bacteria. • This study is helpful to determine the best cleaning procedure to be implemented. The Alcobaça Monastery (Portugal), a UNESCO World Heritage Site, currently exhibits a high degree of surface alterations of the stone architectural elements inside the church, including an extensive pink coloration in the walls and columns, bacteria biofilms, and salt efflorescences. The main goal was to identify the microbiota that colonizes the walls and columns of this monument, to help custodians and conservators-restorers in the selection of the correct procedure to be adopted for the conservation of the monument. Regarding the observed pink discoloration, and considering previous studies, we hypothesize that is caused by biofilms formed by bacteria or other microorganisms that produce pigments of the same color, particularly carotenoids. Curiously, a distinct phenomenon was noticed: the pink discoloration always seems to appear at a very similar height in most of the columns and walls, starting at 40 cm to the floor and associated with the presence of salts on the walls. Using high-throughput sequencing approaches, we were able to characterize the microbial community present. We identified several bacteria that are producers of pink pigments and halotolerant such as Rubrobacter radiotolerans, Domibacillus robiginosus, Bacillus licheniformis and Halalkalicoccus sp. that develop in areas of high salinity. [ABSTRACT FROM AUTHOR]

• Three fungi were identified as mummified skin biodeteriogens. • Volatile EOs showed antifungal activity against the skin biodeterioration fungi. • Oregano showed to be the most effective antifungal volatile EO. The study of the potential use of essential oils in the field of Cultural Heritage has increased in the last decade due to their demonstrated antimicrobial potential and absence of toxicity. This work aimed at assessing, for the first time, the volatile antifungal activity of two essential oils (EOs) (Origanum vulgare and Syzygium aromaticum) against fungi isolated from biodeteriorated archaeological mummified skin. The object of study was a mummified Mustela frenata from the Tiahuanaco culture of Bolivia. The fungi found on the archaeological animal's skin were preliminarily isolated and identified by DNA-based analysis. Subsequently, the volatile essential oil biocidal activity was evaluated on parchments inoculated with the isolated fungi (Aspergillus tabacinus, Aspegillus tennesseensis, and Trichoderma longibrachiatum). Vapour tests were conducted in Petri dishes and parchment specimens to assess the fungicidal effect of volatile components of EOs. The volatile EOs used in this study showed antifungal activity against the tested fungi. The oregano showed to be the most effective EO in the in vitro and parchment tests for the three fungal strains. The use of EOs, particularly oregano EO, represents a promising green strategy for the sustainable conservation of organic-based cultural assets. [Display omitted] [ABSTRACT FROM AUTHOR]

Caves, with distinctive features and specialized ecosystems, harbour microorganisms that have adapted metabolically to survive in seemingly harsh conditions with limited essential elements. Despite the potential threat of biodeterioration to subterranean heritage due to microbial proliferation, caves serve as vital reservoirs of bioactive compounds produced by subsurface-adapted microorganisms. These microorganisms form biofilms, producing diverse bioactive compounds with properties such as antimicrobial, antioxidant, and anticancer capabilities. We conducted a comprehensive study with different bacterial strains isolated from terrestrial and marine caves (Escoural cave and in different caves on the Lanzarote island and on Selvagem Grande island). Extracts from these strains demonstrated potential in inhibiting the growth of pathogenic bacteria, showed robust antioxidant effects, and exhibited antiproliferative activity against breast cancer cells, moreover some of these extracts (Knoellia sp. CI04-s2.2, Brevibacillus sp. MR02B-s3, Bacillus sp. CK03-s2 and Bacillus sp. SD03-s6) present more than one bioactivity. This study unveiled the potential of cave bacterial strains as valuable sources of bioactive compounds, with implications for the development of novel biocides and pharmaceuticals. Bioprospecting within these unique environments offers a distinct opportunity not only to explore and safeguard these ecosystems but also to promote the development of eco-friendly, safe, and sustainable solutions. [Display omitted] • Bacteria isolated from unexplored subterranean environments. • Bioactive compounds produced by cave-dwelling bacteria. • Biocompounds exhibit antimicrobial, antioxidant, and antiproliferative properties. • Bioprospection in pristine realms for biotechnological sustainability. [ABSTRACT FROM AUTHOR]