title: Molecular monitoring of the microbial dynamics occurring on historical limestone buildings during and after the in situ application of different bio-consolidation treatments.
abstract: Microbially Induced Carbonate Precipitation is proposed as an environmentally friendly method to protect decayed ornamental stone and introduced in the field of preservation of Cultural Heritage. Recent conservation studies performed under laboratory conditions on non-sterile calcarenite stones have successfully reported on the application of a suitable nutritional solution, inoculated and non-inoculated with Myxococcus xanthus, as a bioconsolidation treatment. Furthermore, this procedure has been applied in situ, very recently, to selected historical buildings in Granada, Spain. For the first time, we evaluate the efficiency and risks of the in situ application of the above mentioned treatments onto two historical buildings in Granada. The evaluation consists of a detailed investigation of the micro-biota actively growing during the seven days of the treatments--short-term monitoring and of that remaining on the stones after six and twelve months of the application--long-term monitoring. A molecular strategy, including DNA extraction, PCR amplification of 16S rRNA sequences, construction of clone libraries and fingerprinting by DGGE (Denaturing Gradient Gel Electrophoresis) analysis followed by sequencing was used to gain insight into the microbial diversity present on the differentially treated stones. The monitoring of M. xanthus was performed by PCR using species-specific primers. Similar dynamics were triggered on both buildings by the application of the nutritional solution (inoculated or non-inoculated). 16S rDNA sequencing revealed the dominant occurrence of members belonging to the Firmicutes and Proteobacteria during the seven days of the treatment, whereas after one year the order Bacillales of the phylum Firmicutes was the predominantly detected microorganisms. M. xanthus could be detected only during the seven days of the treatment. The treatments seem to activate no dangerous microorganisms and furthermore, to select the remainder of a homogeneous group of carbonatogenic bacteria on the stones after a long period of time.
authors.affiliation: Institute of Applied Microbiology, Department of Biotechnology, Vienna Institute of Bio Technology (VIBT), University of Natural Resources and Life Sciences, Muthgasse 11, A-1190 Vienna, Austria. Joerg.Ettenauer@boku.ac.at
authors.forename: Jörg
authors.initials: J
authors.lastname: Ettenauer
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Piñar
authors.forename: Katja
authors.initials: K
authors.lastname: Sterflinger
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Gonzalez-Muñoz
authors.forename: Fadwa
authors.initials: F
authors.lastname: Jroundi
mesh_terms: D001419:Bacteria / Q000145:classification / Q000302:isolation & purification*; D002119:Calcium Carbonate / Q000737:chemistry*; D003001:Cloning, Molecular; D003247:Conservation of Natural Resources / Q000379:methods*; D003252:Construction Materials / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis; D004783:Environmental Microbiology; D008969:Molecular Sequence Data; D016941:Myxococcus xanthus / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013030:Spain
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D002119:Calcium Carbonate