Diversity and abundance of carbohydrate active enzymes revealed by metagenomic analyses of solfatara Pisciarelli. Archaea

The study of the communities of hyperthermophilic microorganisms populating volcanic sites is of interest to understand their adaptation and evolution to extreme conditions and to exploit their reservoir of biocatalysts. In fact, the intrinsic stability of extremozymes to common protein denaturants makes them interesting tools for biotransformations in industrial applications. With this in mind, we embarked in the exploration of the diversity of the solfataric field of Pisciarelli, Agnano (Naples, Italy). We report here the results of a metagenomic analysis of two mud/water pools that, although distant only 4 meters, greatly differ in both temperature and pH (T=85°C and pH 5.5; T=92°C and pH 1.5, for Pool1 and Pool2, respectively). The DNA from Pool1 was extracted from the mud/water suspension while Pool2 DNA was obtained from the sediment. Deep sequencing by Illumina technology and the following in-silico analysis highlighted the predominance of the phylum Crenarcheaota, but with great genera variance that reflected the difference in chemico-physical parameters of the two pools. The abundance of genes involved in the carbohydrate metabolism, as revealed by the analysis of the functional categories, prompted us to explore the diversity of hyperthermophilic carbohydrate-active enzymes (cazymes). The in silico analysis of the identified families, together with the specificity of the characterized cazymes and the classification of the vegetation surrounding the sampling site, pointed to the complex nature of the carbohydrate active enzymes set (cazome) of the hydrothermal vent.