Fishing thermophiles in temperate soils. Their role, diversity, distribution and applications

Abstract

In the last years, the presence of thermophiles in temperate soils and sediments has been confirmed in every tested sample. However, no information is available on their potential contribution to the temperate ecosystems and environmental influence on their distribution. In this study, we will walk through the importance of minorities within environmental microbial communities and specifically the thermophiles in temperate soils and sediments. The role, if any, of thermophiles in these environments as well as their metabolic capabilities are studied. Enzymatic activities in soils were also surveyed to evaluate their importance and genomic studies allowed to decipher their distribution in environments with different characteristics. The biotechnological application of these thermophiles is studied by characterizing some of their enzymes. A potential ecological role for these bacteria is envisioned in these systems as contributors to carbon, nitrogen and sulfur cycling leading to a release of ammonium and sulfate as a product of the consumption of organic matter. Genomic analyses and comparisons provided evidence on the existence of a singular metabolic pathway explaining the net release of sulfate and ammonia to the environment. Enzymatic activity within the thermophilic range of temperatures in soils and sediments suggests a relevance of these thermophiles in terrestrial ecosystems and previous misestimated of extracellular enzyme activity in soils. Genes encoding for enzymes with potential biotechnological interest were cloned and expressed as recombinant enzymes which activity was characterized. Soil thermophiles are omnipresent in temperate soils and sediments. They play an important role in these systems taking advantage of high temperature events which are relatively frequent at low latitudes. Besides, they represent a potential highly diverse source of biocatalysts for industrial applications. This talk will bring up the investigations carried out at our laboratory during the last years on the topic of thermophiles as inhabitants of temperate soils and sediments and will place these findings into a global perspective of current understanding of soil microbiology