Evolutionary investigation of dolomite biomineralization by EPS secreting bacteria in simulated environments

• Grant number: 17/02453-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2017
• End date: July 31, 2018
• Field of knowledge: Interdisciplinary Subjects
• Principal Investigator: Douglas Galante
• Grantee: Bianca de Freitas Brenha
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Campinas , SP, Brazil
• Associated research grant: 16/06114-6 - The Neoproterozoic Earth System and the rise of biological complexity, AP.TEM
• Associated scholarship(s): 17/23397-4 - Evolutionary investigation of the biomineralization of dolomite by EPS-forming bacteria from Lagoa Vermelha in Rio de Janeiro, Brazil, BE.EP.IC

Abstract

The precipitation of dolomite in the Earth's current sedimentary environments occurs, for the most part, mediated by microorganisms. The way in which these bacteria are able to facilitate or induce biomineralization has not yet been fully elucidated in the literature. However it is known that they secrete an EPS (extracellular polymeric substance) matrix that facilitates the formation of an ideal environment for precipitation of dolomite. The ability to secrete EPS is extremely widespread among microorganisms and may perform several different functions, including a common mechanism for protecting extremophiles from adverse conditions. In the present project, samples collected in Lagoa Vermelha (Araruama, RJ) by the Environmental Sciences group of LNLS will be used for isolation and subsequent identification by 16S rRNA of EPS producing bacteria. The isolates thus obtained will be submitted to different environmental simulations, varying intensity and time of environmental UV radiation, and their capacity of bioprecipitates, especially dolomite, will be studied by analytical techniques (Raman spectrometry, X-ray fluorescence and diffraction of X ray). After the simulations, the resulting samples will be analyzed to evaluate the survival of the colonies according to the different radiation parameters through counting of colony forming units (CFU). In addition the samples will be analyzed in more detail, evaluating plasma membrane damage, using fluorescence microscopy techniques and analyzing changes in EPS production. Finally, phylogenetic trees will be constructed to evaluate the degree of similarity between the species capable of producing bioprecipitated minerals, and to allow an evolutionary view of this phenomenon. (AU)