Surface reactivity of the sheath-forming Iron/manganese-oxidizing bacterium leptothrix: Implications in sheath encrustation and metal mobilization

• Grant number: 22/00016-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: August 01, 2022
• End date: July 31, 2023
• Field of knowledge: Interdisciplinary Subjects
• Principal Investigator: Fabio Rodrigues
• Grantee: Maicon Nascimento Araújo
• Supervisor: Kurt Konhauser
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: University of Alberta, Canada
• Associated to the scholarship: 20/03430-0 - Iron/manganese-oxidizing bacteria from ferruginous environments of Minas Gerais (Brazil): implications in Geomicrobiology and Astrobiology, BP.DD

Abstract

Cell surface charges, resulting from the acid-base equilibrium of organic ligands, are known to play important roles in microorganisms nutrition, adherence to surfaces and metal interaction. A quantitative approach is allowing researchers to model the bacteria interactions with metals, minerals and nutrients. These models are fundamental for a better understanding of microbial ecophysiology and life-driven events of Earth history; also, it provides tools for bioremediation management and prospection. In this regard, Leptothrix is an interesting bacterial genus to be explored. It is a freshwater, iron and manganese-oxidizing bacteria known for the generation of hollow biomineralized sheaths (microtubules). Exploring its ability to bind iron and manganese oxides in its sheathes is a key to understand its biomineralization processes, metal mobilization and ecophysiological roles; with implications for interpretation of biogenicity of ancient analogous structures (microfossils) and the potential use of encrusted sheaths as biosignatures. However no study has yet attempted to, quantitatively, determine Leptothrix'' sheath and cell surface charges as well as its ability to bind and transport metals. Here we propose to access this information using potentiometric titrations, attenuated total reflectance Fourier transform infrared (ATR-FTIR) and Cd-adsorption quantifications at Prof. Kurt Konhauser's laboratory in the University of Alberta, Canada. (AU)