ABSTRACT
The members of the genus Rhodococcus are aerobic, non-motile and non-sporulating bacteria belonging to the actinomycetes group. These microorganisms are taxonomically close to Nocardia, Mycobacterium and Dietzia genera. They are usually found in diverse environments, such as tropical and artic soil, deserts as well in marine and deep-sea sediments (Whyte et al. 1999, Heald et al. 2001, Peressutti et al. 2003, Alvarez et al. 2004, Luz et al. 2004, Peng et al. 2008). The huge metabolic repertoire of these microorganisms as well as their capability to adapt their metabolism to a wide range of nutritional conditions, are in part responsible for the occurrence of these actinobacteria in different natural ecosystems. The central metabolism of rhodococci provides all necessary intermediates for the biosynthesis of a wide range of molecules which are used for assembling complex macromolecules, secondary metabolites and cellular structures. This extraordinary biosynthetic capability of rhodococci is combined with a broad catabolic ability. These microorganisms seem to have the potential
Regional Centre for Research and Development (CRIDECIT), Faculty of Natural Science, University of Patagonia San Juan Bosco, Ruta Provincial Nro 1-Ciudad Universitaria, (9000) Comodoro Rivadavia, Chubut, Argentina. *Corresponding author: halvarez@unpata.edu.ar
to use alternatively different glycolytic pathways, such as EMP or ED pathways, the PP pathway, and a partial or fully functional tricarboxylic cycle (TCA) in both, oxidative and reductive directions according to the experimental conditions (Alvarez 2010). Moreover, rhodococci posses the ability to produce variable amounts of storage compounds, such as polyhydroxyalkanoates (PHA), triacylglycerols (TAG), glycogen and polyphosphate, which probably permit cells to respond rapidly to changes in nutritional state and to balance metabolism under different environmental conditions (Hernández et al. 2008). One relevant feature of rhodococci is their ability to degrade and transform a wide range of pollutant compounds, such as hydrocarbons with diverse chemical structures, pesticides, xenobiotics and explosives (Warhurst and Fewson 1994, Larkin et al. 2005, Martínková et al. 2009). All these properties make such microorganisms promising candidates for bioremediation of polluted environments. In this context, some success has been achieved in bioremediation of contaminated soil, air and waters using rhodococci as bioaugmentation agents (Kuyukina and Ivshina 2010).
