Institute for Natural Sciences and Technology in the Art, Academy of Fine Arts Vienna, Schillerplatz 3, A-1010 Vienna, Austria.
Department of Applied Life Sciences/Bioengineering/Bioinformatics, FH Campus Wien, Favoritenstrasse 226, A-1100 Vienna, Austria.
Sci Total Environ. 2023 Dec 15;904:166737. doi: 10.1016/j.scitotenv.2023.166737. Epub 2023 Sep 1.
Salt-weathering is a deterioration mechanism affecting building materials that results from repetitive cycles of salt crystallisation-dissolution in the porous mineral network under changing environmental conditions, causing damage to surfaces. However, an additional biodeterioration phenomenon frequently associated with salt efflorescence is the appearance of coloured biofilms, comprising halotolerant/halophilic microorganisms, containing carotenoid pigments that cause pinkish patinas. In this work, two Austrian historical salt-weathered buildings showing pink biofilms, the St. Virgil's Chapel and the Charterhouse Mauerbach, were investigated. Substrate chemistry (salt concentration/composition) was analysed by ion chromatography and X-ray diffraction to correlate these parameters with the associated microorganisms. Microbiomes were analysed by sequencing full-length 16S rRNA amplicons using Nanopore technology. Data demonstrates that microbiomes are not only influenced by salt concentration, but also by its chemical composition. The chapel showed a high overall halite (NaCl) concentration, but the factor influencing the microbiome was the presence/absence of K. The K areas showed a dominance of Aliifodinibius and Salinisphaera species, capable of tolerating high salt concentrations through the "salt-in" strategy by transporting K into cells. Conversely, areas without K+ showed a community shift towards Halomonas species, which favour the synthesis of compatible solutes for salt tolerance. In the charterhouse, the main salts were sulphates. In areas with low concentrations, Rubrobacter species dominated, while in areas with high concentrations, Haloechinothrix species did. Among archaea, Haloccoccus species were dominant in all samples, except at high sulphate concentrations, where Halalkalicoccus prevailed. Finally, the biological pigments visible in both buildings were analysed by Raman spectroscopy, showing the same spectra in all areas investigated, regardless of the building and the microbiomes, demonstrating the presence of carotenoids in the pink biofilms. Comprehensive information on the factors affecting the microbiome associated with salt-weathered buildings should provide the basis for selecting the most appropriate desalination treatment to remove both salt efflorescence and associated biofilms.
盐风化是一种影响建筑材料的劣化机制，它是由于多孔矿物网络中盐的反复结晶-溶解在环境条件变化下，导致表面损坏。然而，与盐析现象经常相关的另一种生物劣化现象是出现彩色生物膜，其包含耐盐/嗜盐微生物，含有类胡萝卜素色素，导致粉红色的铜绿锈。在这项工作中，研究了两座奥地利历史上盐风化的建筑，即圣维吉尔小教堂和莫尔巴赫隐修院，它们都显示出粉红色的生物膜。通过离子色谱和 X 射线衍射分析了基质化学（盐浓度/组成），将这些参数与相关微生物相关联。通过纳米孔技术对全长 16S rRNA 扩增子进行测序来分析微生物组。数据表明，微生物组不仅受盐浓度的影响，还受其化学成分的影响。小教堂显示出高的总卤化物（NaCl）浓度，但影响微生物组的因素是 K 的存在/不存在。K 区域显示出 Aliifodinibius 和 Salinisphaera 物种的优势，它们能够通过将 K 运入细胞的“盐入”策略耐受高盐浓度。相反，没有 K+的区域显示出向能够耐受盐的 Halomonas 物种的群落转移。在隐修院，主要的盐是硫酸盐。在浓度低的区域，Rubrobacter 物种占主导地位，而在浓度高的区域，Haloechinothrix 物种占主导地位。在古菌中，除了在高硫酸盐浓度下 Halalkalicoccus 占主导地位外，Haloccoccus 物种在所有样品中都占主导地位。最后，通过拉曼光谱分析了在两座建筑中都可见的生物色素，显示出在所研究的所有区域中相同的光谱，无论建筑和微生物组如何，证明粉红色生物膜中存在类胡萝卜素。关于影响与盐风化建筑相关的微生物组的因素的综合信息应该为选择最适当的脱盐处理提供基础，以去除盐析和相关的生物膜。
