NATURAL ANTIBIOFOULING AGENTS AS NEW CONTROL METHOD FOR PHOTOTROPHIC BIOFILMS DWELLING ON MONUMENTAL STONE SURFACES

Five natural antibiofoulants with terrestrial (capsaicine - CS, cinnamaldehyde - CI) and marine origin (zosteric acid - ZA, poly-alkylpyridinium salts - pAPS and Ceramium botryocarpum extract - CBE) have been selected and tested against phototrophic biofilm formation on the stone surfaces for their inhibitory properties. The antibiofouling agents (ABAs) were incorporated into two commercial silicone based coatings (Silres BS OH 100 - S and Silres BS 290 - W). In this work, phototrophic growth was evaluated by epifluorescence microscopy and semi-quantitative image analysis. The results showed an inhibitory efficiency for almost all tested ABAs. However, this efficiency has been found for short time or when the incorporating agent were incompletely cured. Among the ABAs tested, the poly-alkylpyridinium salts and cinnamaldehyde incorporated into Silres BS 290 showed the best inhibitory efficiency

A Bacillus subtilis cell fraction (BCF) inducing calcium carbonate precipitation: biotechnological perspectives for monumental stone reinforcement

Abstract Monumental stone decay is a consequence of the weathering action of physical, chemical and biological factors, which induce a progressive increase in porosity. To cope this degradation, bacterial calcium carbonate mineralization has been proposed as a tool for the conservation of monumental calcareous stones. The advantage of this kind of treatment is to obtain a mineral product similar to the stone substrate, mimicking the natural process responsible for stone formation. In this work, the possibility to induce CaCO3 mineralization by a bacteria-mediated system in absence of viable cells was investigated and tested on stone. Our results showed that Bacillus subtilis dead cells as wells as its bacterial cell wall fraction (BCF) can act as calcite crystallization nuclei in solution. BCF consolidating capability was further tested in laboratory on slab stones, and in situ on the Angera Church, a valuable 6th century monumental site. New crystals formation was observed inside pores and significant decrease in water absorption (up to 16.7%) in BCF treated samples. A little cohesion increase was observed in the treated area of the Angera Church, showing the potential of this application, even though further improvements are needed

Deterioration of an Etruscan tomb by bacteria from the order Rhizobiales

7 páginas, 4 figuras, 29 referencias.The Etruscan civilisation originated in the Villanovan Iron Age in the ninth century BC and was absorbed by Rome in the first century BC. Etruscan tombs, many of which are subterranean, are one of the best representations of this culture. The principal importance of these tombs, however, lies in the wall paintings and in the tradition of rich burial, which was unique in the Mediterranean Basin, with the exception of Egypt. Relatively little information is available concerning the biodeterioration of Etruscan tombs, which is caused by a colonisation that covers the paintings with white, circular to irregular aggregates of bacteria or biofilms that tend to connect each other. Thus, these colonisations sometimes cover extensive surfaces. Here we show that the colonisation of paintings in Tomba del Colle is primarily due to bacteria of the order Rhizobiales (Alphaproteobacteria), which were likely influenced by the neighbouring rhizosphere community and the availability of nutrients from root exudates.This work was funded through the projects CGL2010-17183, 201030E011 and Consolider 2007-00058. M.D.H. was supported by a JAE Research Fellowship from CSIC, and S.C. was supported by a Juan de la Cierva contract.Peer reviewe

Placemaking and Networking of Heritage for Sustainable Tourism

The heritage as emotional investment of the citizens is important resource for the communities affirming their local identity and establishing the great potential for development of tourism. The richness in the cultural heritage and historic layers are one of the main characteristics of European cities and towns. The paper will focus on how small and medium sized towns in Europe can enhance heritage with the increase a sustainable tourism that is competitive by using the different tools (digital, collaborative, design) in networking of the heritage sites and placemaking. The small and medium towns are in the focus of the research because they are shrinking during the last few decades that is caused by the depopulation and socio-economic factors. Developing of small and medium cities through their heritage promotions, enhance tourism as a milestone for their urban development and promotion. Sustainable development of tourism could be achieved by strengthening the ties between different actors in the process of placemaking, enhancing the relations and interactions between tourism, cultural heritage and local inhabitants using digital tools. One of the goals is to try to depict relation between physical heritage networks and linked digital tools. Cultural assets are of great importance for revitalize small cities and endargered towns, but these are not enough if investments are missing. It is necessary to attract them for living again, rebuilding the lost commercial activities and public services. Heritage and tourism are closely connected, from one hand heritage is one of the major stimuly for cultural tourism and on the other hand heritage sites can improve their preservation by tourism. But the relationship between the two can be conflictual due to a possible overuse and consequent deterioration of heritage sites due to different needs and strategies between the two fields. A new placemaking strategy must be developed that considers how tuorism can influence (positive or negative) the suistanaibility of cultural heritage overview as well as heritage role in the local identity. By critical analysies of literature and selected cases from different countries in Europe, we hope to present proposals for strenghtening the heritage potentials for sustainable tourism in small and medium sized towns, focusing on the junction of scientific theories and practical experiences. The paper highlights the findings and lessons learned from selected cases from Portugal, Italy, Croatia, Greece, Romania and Serbia. Final intentions of the paper are to present the variety of possible ways to use networking of heritage site and stakeholders as a medium for placemaking in favour of both local population and prospective tourists

Preliminary Study on Controlling Black Fungi Dwelling on Stone Monuments by Using a Microwave Heating System

Microcolonial black fungi have their natural ecological niche on rocks and walls of hypogean environments, playing an important role in the deterioration of materials and aesthetical alteration of monumental stones and mortars. Three black fungi (Sarcinomyces sp., Pithomyces sp. and Scolecobasidium sp.) have been isolated from cultural assets of historical interest. These fungal strains have been used to test the microwave heating method as a new control methodology for eradicating the fungal biological growth on cultural stone artifacts. This methodology is based on a 2.45 GHz microwave electromagnetic radiation, generated by a new apparatus with an appropriate applicator. The first results showed the best dose of 65°C for three minutes, for all the investigated fungal strains. This methodology is very promising because is safety for the operator and the environment, and can be easily applied on site. The use of this method to kill biodeteriogens can avoid the application of chemicals formulates potentially dangerous for substrates and environment