Abstract
Traditional methods normally used to study the microbial populations present on artwork surfaces are time-consuming and often do not reveal the specific characteristics of the microbial ecotypes, The development of new powerful tools from molecular biology (such as polymerase chain reaction [PCR], simple and effective cloning and electrophoretic systems [SSCP, DGGE, TGGE] for nucleic acids separation, automated DNA sequencing facilities and wide databases which rapidly accumulate sequences of signature bacterial genes such as ribosomal genes) have greatly amplified the resolution power of microbial communities analysis (Rolleke et al., 1996; Wollenzien et at, 1997; Moreira and Amils, 1996). In this report, we analyse the contribution of different molecular methods and techniques in investigating the microbial diversity on stoneworks, in relation to the microbe itself and to genes which may play some role in the metabolism of organic air pollutants, and in detecting, by means of molecular probes, particularly dangerous microorganisms whose presence is suspected. A study of the microbial biodiversity of Carrara marble and other stone materials, particularly the presence of Geodermatophilus-like organisms, is reported. Among the isolated strains, a strain phenotypically similar to Geodermatophilus but genotypically quite divergent from this species has been identified. The partial sequence of the 16S rDNA showed that the strain may represent a new species and even a new genus of the actinomycetes, Moreover, a method to detect directly on the stone samples the presence of genes involved in aromatic hydrocarbon biodegradation is proposed in order to demonstrate the capability of microorganisms to grow by degrading aromatic atmospheric pollutants, Finally a method is proposed for the detection of Bacillus strains.In particular, a PCR-based system has been developed to monitor directly on stone samples and without isolation the members of the B. cereus group, which are widespread in the environment and are frequently found on altered stoneworks (Zanardini et al., 1997). In several cases the bio-molecular techniques proved to be a valid tool for the investigation of artwork biodeterioration.