Soil is the most complex of all microbial habitats. Tropical soils have high levels of biodiversity and microorganisms that display fascinating mechanisms for interaction and biotransformation, thus regulating the mobility of chemical compounds in the environment. This paper will provide an understanding the relationship between chemical compounds present in a tropical soil and the microorganisms isolated from different sampling points in the biologically diverse area of Lepanto, Costa Rica. Microbiological (bacterium and fungi culture media), biochemical (oxidation fermentation and catalase test), molecular (ITS and 16S gene fragments), thermal (TGA), and spectroscopic (FTIR, SEM-X-ray) techniques were used for this purpose. Four bacterial species, Klebsiella quasipneumoniae, Klebsiella pneumoniae, Micromonospora sp. and Paenibacillus sp., and three fungal species, Penicillium rubens, Penicillium stekii and Meyerozyma guilliermondii, were identified. The soil chemical composition allowed the identified microorganisms to be associated with fatty acid groups, humic substances, aromatic compounds, conjugated ketones and carboxylic groups. In addition, metals present in the soil (Al, Mg, C, O, Si and Fe) were correlated with the activity of these microorganisms. The present study highlights the potential utility of the combined use of inference tools to identify ecologically meaningful microorganismal associations in environmental samples and the chemical compounds in a tropical soil.
