Characterization of stress tolerance and metabolic capabilities of acidophilic iron-sulfur-transforming bacteria and their relevance to Mars - Dissertation

Aug 29, 2026

This dissertation characterizes stress tolerance and maintenance metabolic capabilities of acidophilic iron-sulfur-transforming bacteria and evaluates their relevance for potential life in Martian environments. The work addresses Mars as a target for astrobiology by reviewing past and present environmental conditions, including water-related evolution, plausible microbial metabolisms, and analog sites. It further examines how environmental stressors such as water limitation, salinity, low temperature, radiation, and biofilm formation influence microbial resistance, survival strategies, and viability, linking experimental methods to survival under extreme conditions.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages257

Reading Time10 h 48 min

AccessFree to download

Introduction

The search for life on Mars

Findings of the Viking mission

Mars in the past and present

The history of Mars and the possible origin of life

Present Mars and potential microbial metabolisms

Rio Tinto as a Mars analog study site

Acidophilic iron-sulfur bacteria

Environmental stressors and microbial resistance strategies

Maintenance metabolism and methods for viability determination

Open fields

Objectives

Materials and Methods

Chemicals

Bacterial strains and cultivation

Bacterial strains

Media, buffers, and solutions

Characterization of stress tolerance and metabolic capabilities of acidophilic iron-sulfur-transforming bacteria and their relevance to Mars Dissertation zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften – Dr. rer. nat.– vorgelegt von Anja Bauermeister aus Leipzig Im Fachbereich Chemie der Universität Duisburg-Essen Die vorliegende Arbeit wurde im Zeitraum von März 2009 bis Dezember 2012 im Arbeitskreis von Prof. Dr. Hans-Curt Flemming am Biofilm Centre (Fakultät für Chemie) der Universität Duisburg-Essen und in der Abteilung Strahlenbiologie (Institut für Luft-und Raumfahrtmedizin, Deutsches Zentrum für Luft-und Raumfahrt, Köln) durchgeführt. Tag der Einreichung: 07.12.2012 Tag der Disputation: 23.04.2013 Gutachter: Prof. Dr. H.-C. Flemming Prof. Dr. W. Sand Vorsitzender: Prof. Dr. C. Mayer Erklärung / Statement Hiermit versichere ich, dass ich die vorliegende Arbeit mit dem Titel „Characterization of stress tolerance and metabolic capabilities of acidophilic ironsulfur-transforming bacteria and their relevance to Mars” selbst verfasst und keine außer den angegebenen Hilfsmitteln und Quellen benutzthabe, und dass die Arbeit in dieser oder ähnlicher Form noch bei keiner anderen Universität eingereicht wurde. Herewith I declare that this thesis is the result of my independent work. All sources and auxiliary materials used by me in this thesis are cited completely. Essen, 07.12.2012 Table of contents Abbreviations ........................................................................................ 0 1 Introduction .................................................................................. 1 1.1 The search for life on Mars...................................................................... 1 1.1.1 Findings of the Viking mission................................................................. 1 1.2 Mars in the past and present................................................................... 4 1.2.1 The history of Mars and the possible origin of life ................................... 4 1.2.1.1 Water and environmental evolution on early Mars ........................... 4 1.2.1.2 Implication for the evolution of life .................................................... 8 1.2.2 Present Mars and potential microbial metabolisms ................................. 9 1.2.2.1 Physical and geochemical conditions on present-day Mars ............. 9 1.2.2.2 Water on Mars today? .................................................................... 11 1.2.2.3 Permafrost environment and methanogenesis ............................... 12 1.2.2.4 Potential electron donors and acceptors on Mars for chemolithotrophic metabolism ....................................................................... 14 1.2.2.5 Hypothetical microbial food web in the subsurface of Mars ............ 16 1.2.3 Rio Tinto as a Mars analog study site ................................................... 19 1.3 Acidophilic iron-sulfur bacteria ............................................................ 22 1.3.1 Acidithiobacillus ferrooxidans ................................................................ 23 1.3.2 Sulfobacillus thermosulfidooxidans ....................................................... 25 1.4 Environmental stressors and microbial resistance strategies .......... 26 1.4.1 Water stress .......................................................................................... 26 1.4.1.1 Desiccation ..................................................................................... 27 1.4.1.2 Salt stress....................................................................................... 28 1.4.2 Low temperatures ................................................................................. 29 1.4.3 Radiation ............................................................................................... 31 1.4.3.1 Ultraviolet

FAQs

What is the central research focus of this dissertation?

It investigates stress tolerance and metabolic capabilities of acidophilic iron-sulfur-transforming bacteria and assesses how these traits relate to the possibility of life on Mars.

Which kinds of Martian-relevant stressors are considered?

The work covers water stress (desiccation and salt stress), low temperatures, and radiation, and discusses biofilms as a survival strategy.

How are bacterial strains and cultivation materials handled in the study?

The dissertation outlines bacterial strains and detailed media and solution components, including basal salt medium, trace elements, and specific iron stock solutions, together with cultivation conditions.

Aug 29, 2026

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