Cyanobacteria and mud therapy

The physiological effects of mature thermal mud are partly attributable to heat and probably to the percutaneous passage of electrolytes in solution (Odabasi et al., 2008; Tateo et al. 2009), but they depend greatly on what happens during the “maturation” process. This process, necessary to optimize the therapeutic characteristics of the mud, consists of letting the mud “rest” in special tanks for about 60 days (Galzigna et al., 1996).

 

During that period, mud is constantly submerged under thermal water at a medium temperature which, in addition to modifying its chemical-physical characteristics (e.g. plasticity, viscosity, etc.), favors the development of a complex community of oxygenic thermophilic and/or thermotolerant photoautotrophic microorganisms (i.e. the microorganisms that do photosynthesis, such as plants) and heterotrophs (the microorganisms that do not photosynthesize, for example, protozoa). Among these microorganisms, the cyanobacteria are the most representative, both for colonization and produced biomass. The cyanobacteria that colonize mainly above the mud surface form the characteristic green-blue “felt”. At present, 11 cyanobacteria strains have been isolated from the mud of the Euganean area and are kept in culture in the laboratories of the Biology Department of the University of Padua and are characterized both at the morphological and molecular levels (Moro et al., 2007, 2010).

 

 

In addition to cyanobacteria, the thermal mud of the Euganean area is also colonized by Diatoms. Compared to cyanobacteria, however, their presence is limited to 2-3 species and one of these has recently been characterized as Navicula veneta (Moro et al., 2010). As described by various authors, diatoms, albeit with some exceptions, do not tolerate temperatures higher than 50° C while cyanobacteria are more thermotolerant even if, except for some forms of Synechococcus able to live at 73-74°C., they do not resist at temperatures higher than at 50-60° C (Edwards et al., 1997; Miller and Castenholz 2000; Balme et al., 2001).

 

Bacteria are certainly involved in the maturation process. Current knowledge, however, is limited to only two species: one of these is Thermoanaerobacter italicus (strain Ab9), a new spore-forming anaerobic thermophilic bacterium isolated in the Euganean area as well as in other spa facilities in Italy (Kozianowski et al., 1997); the other, Anoxybacillus thermarum (strain AF / 04T), is strictly aerobic and, like the previous bacterium, is a new thermophilic species isolated from the mud of Abano Terme (Poli et al., 2009).

 

The photosynthetic organisms (cyanobacteria and diatoms), due to their needs for light and gas exchange, develop only on the most superficial layer of the mud while the aerobic bacteria, as well as the protozoa, are able to colonize the mud as far as the oxygen is available.

 

 

Continue reading with Thermal mud diatoms