Researchers of the Departments of Mineralogy and Petrology and of Microbiology of the University of Granada have managed to find out the amazing applications of a common soil bacteria, Myxococcus Xanthus, in ornamental element restoration of listed buildings. The microorganism, harmless to people, allows to rebuild damaged elements of these buildings with high accuracy through a perfect cement that increases on the original material, strengthing it but allowing it “to breath“ without trace or spores that endanger it. Once its task is over, the bacteria simply vanishes.
The persons in charge of this research work “Conservation of Ornamental Stone by Calcite Precipitation Inducted by Myxococcus xanthus” are lecturers Manuel Rodríguez Gallego, Professor of the Department of Mineralogy and Petrology of the Faculty of Sciences and director of the scientific research; María Teresa González-Muñoz, Professor of Microbiology; Carlos Rodríguez Navarro, teacher of the Department of Mineralogy and Petrology and researcher Koutar ben Chekroun.
The joint research work between both departments has culminated the first laboratory stage, which started a year ago, in a spectacular success and the second stage, the “mesoscale” one, has already started, consisting in working with ornamental elements in a closed space. The last stage will be in outdoors, in “macroscale” conditions, in such an emblematic building as the Cathedral of Granada, the Alhambra or any of the exceptional buildings of the city.
The collaboration between both departments started about twelve years ago when Professor González-Muñoz found out that Myxococcus, a microorganism known since many years and used to make antibiotics, also made minerals. The Professor found out that “as for mineralization, the microorganism is very active and in appropriate conditions it can produce anything. Up to know we have designed culture mediums and conditions in which the bacterium produces minerals of different nature and high beauty: phosphates, carbonates, sulfates, and even quartz”.
The research work carried out in the Faculty of Sciences applied its finding to the conservation of the historical heritage, a subject in which researchers of the Dpt. of Mineralogy and Petrology were already working since the late eighties. Manuel Rodríguez Gallego explains that industrial development, heating, car engines, etc, “have created a very aggressive climate which is endangering irrecoverable goods which are, in addition, a source of income as they are tourist attractions”.
Different research groups work all over the world looking for solutions for this problem, which has been considered “especially important” by the European Union. However, the director of the work states, although bioremediation processes has been used with other microorganisms, “results have been very poor up to now. We have been lucky that we have found a microorganism that has provided extraoirdinarily positive results and can explain a lot of geological phenomenons”.
Professor Carlos Rodríguez explains that thanks to the mineralizing capacity of this kind of bacterium “up to now, we have managed to strength calcite materials producing cement, a kind of inorganic glue that joins all the material grains and achieving characteristics very similar to those of the original material”.
In addition, the material that produces the microorganism is “more resistant and lasting than the original; it can probably last for many years without suffering from alterations”. When the research work concludes, the microorganism will be applied directly to stones or ornamental elements choosen after creating a culture of enough celular density that will be “feeded” while necessary for it to increase on the stone.
The importance of the work carry out by researchers from Granada reflects in the fact that it has been selected by the American Society for Microbiology as “the best of the bests of April” and it has been published in its journal “Applied and Environmental Microbiology”, one of the eleven journals that it publishes. Reviews about this research work have been published in such prestigious journals as “Nature” and “Science”.
Further information:
– Manuel Rodríguez Gallego, Professor of the Department of Mineralogy and Petrology. Research Director. Phone number: 958 243339 E-mail: mrgalleg@goliat.ugr.es
– María Teresa González-Muñoz, Professor of Microbiology. Phone number: 958 242858. E-mail: mgonzale@goliat.ugr.es
– Carlos Rodríguez Navarro, teacher of the Department of Mineralogy and Petrology. 958 246616
E-mail: carlosrn@goliat.ugr.es
