The hydrothermal resources of medium and low enthalpy in the diversification of primary sources of energy and biotechnology applications: A case study at the San Bartolome de Los Baños geothermal zone, Guanajuato, Mexico

Abstract

In the present study, the hydrothermal sources of the community of San Juan de Los Llanitos, Apaseo el Alto, Guanajuato, were physically chemically, and microbiologically characterized. The characterization aims to diversify the use of primary sources of energy, particularly their use in microbial biotechnology. Two types of energy resources were recognized in this geothermal zone: one related to the geothermal energy of medium enthalpy (150 °C > T > 90 °C), while the other is of low enthalpy (90 °C > T > 25 °C). The medium energy resource can be used to produce electricity using binary cycle power plants. The waters of the San Bartolomé de Los Baños geothermal zone are of sulfurous sodium chloride type, hyperthermal and superthermal, with a colloidal content, ionic activity, and a presence of chemical components that can be used for balneotherapeutic purposes. Hot springs are extreme ecosystems that, despite having high temperatures, constitute an environment for many thermophilic microorganisms (bacteria, cyanobacteria, and diatoms). The identification of bacteria (Brevibacillus agri, Paenibacillus sp.), cyanobacterias, and diatoms in the study area could be used in the biotechnological application and as indicators of the water quality and the environment. From thermophilic bacteria found in the studied waters, enzymes can be obtained. Such enzymes include amylases, cellulases, proteases, hydrolases, lipases, DNA polymerases, and nitrates, that could be used in the food industry, paper, detergents, medicines, and toxic waste disposal. Medium and low enthalpy geothermal energy represents an opportunity to promote the diversification of primary energy sources, fight against climate change by reducing CO2 emissions on a global scale, and promote sustainable development of local communities and the region with the implementation of activities such as balneology, therapeutic, biotechnological, and industrial.