Abstract

Deception Island is one of the regions of the Antarctic territory that still retains its geothermal activity, where it’s soil temperatures range from 40°C and 85°C. From a sample collected from this soil a novel bacterial strain was isolated and cultured. This aerobic thermophile, moderately halotolerant, has optimal growth conditions at pH 7.5 and 65°C and is classified as Geobacillus sp. ID17 . An interesting characteristic observed in this microorganism is the presence of Laccase activity detectable in its intracellular crude extract. Laccases are enzyme from the Multicopper oxidase family, that catalyze the oxidation of aromatic compounds with nucleophilic substituents, such as phenols or primary amines. They show an interestingly wide substrate range, which seems to differ among species. To find a laccase activity in Geobacillus ID17 seems surprising considering the geographical environment in which this microorganism was found. Laccases are traditionally associated with the decomposition of plant biomass, which is not in abundance in Deception Island, although laccases are reported to participate as copper resistant determinants in some bacteria (Grass and Rensing 2001). With an enzymatic assay of oxidation of Syringaldazine, a specific substrate for laccases, the activity of this enzyme in the presence of inorganic cations and lignin polymers was studied.