Insights into the Microbial Weathering of Chinese Wooden Ancestral Halls in Guangdong Province

Wooden buildings are facing biodeterioration due to natural weathering. Ancestral halls are traditional Chinese wooden architecture with high artistic value. The research analyzed the microbial diversity of nine ancestral halls in Guangdong Province under subtropical monsoon climates. With amplicon sequencing, we found a common core microorganism group, including Bacillus, Pseudomonas, Paenibacillus, Acinetobacter, Toxicocladosporium, Cladosporium, Aspergillus, and Epicoccum. A total of 8 different species of bacteria and 7 different species of fungi were isolated from Chen Clan Ancestral halls, most of which were proven to be capable of degrading cellulose or lignin. The comparison between damaged and undamaged sites (whether the paint coating is flaked off) revealed similar microbial compositions but with differing abundances. Firmicutes and Ascomycota dominated damaged surfaces, while Proteobacteria and Actinobacteria prevailed in undamaged ones. Notably, Cladosporium, widely present in both sites, emerged as the primary cellulose-degrading genus. Given the similar microbial compositions between damaged and undamaged sites, it is suggested that using paint alone as the exclusive means to protect bare wood is insufficient. Apparent correlation between microorganisms on wooden surfaces and humans showed that the increase of visitor flow rates might impact the microbiota composition on cultural relics. We evaluated the effect of four representative biocides and determined the feasibility of low-concentration Isothiazolinone. This research facilitates a basic understanding of the microbial weathering of ancestral halls and add significant reference for preserving wooden structures.