Microorganisms and Their Metabolic Capabilities in the Context of the Biogeochemical Nitrogen Cycle at Extreme Environments

Abstract

Extreme microorganisms (extremophile) are organisms that inhabit environments characterized by inhospitable parameters for most live beings (extreme temperatures and pH values, high or low ionic strength, pressure, or scarcity of nutrients). To grow optimally under these conditions, extremophiles have evolved molecular adaptations affecting their physiology, metabolism, cell signaling, etc. Due to their peculiarities in terms of physiology and metabolism, they have become good models for (i) understanding the limits of life on Earth, (ii) exploring the possible existence of extraterrestrial life (Astrobiology), or (iii) to look for potential applications in biotechnology. Recent research has revealed that extremophilic microbes play key roles in all biogeochemical cycles on Earth. Nitrogen cycle (N-cycle) is one of the most important biogeochemical cycles in nature; thanks to it, nitrogen is converted into multiple chemical forms, which circulate among atmospheric, terrestrial and aquatic ecosystems. This review summarizes recent knowledge on the role of extreme microorganisms in the N-cycle in extremophilic ecosystems, with special emphasis on members of the Archaea domain. Potential implications of these microbes in global warming and nitrogen balance, as well as their biotechnological applications are also discussed.

Removal of Pharmaceuticals from Water by Adsorption and Advanced Oxidation Processes: State of the Art and Trends

“…Bacteria occupy a dominant place in the biosphere; through their various metabolic capabilities, they support the metabolic cycles that are fundamental to all life on Earth [59]. Researchers are investigating the potential of different bacteria to degrade pharmaceuticals and personal care products (PPCPs) into eco-friendly monomers, which could be an alternative emerging way to eliminate pharmaceutical residues from the ecosystem [60].…”

Water–Sulfuric Acid Foam as a Possible Habitat for Hypothetical Microbial Community in the Cloud Layer of Venus

“…Such compounds can play a few roles in the cloud layer system. Firstly, they can serve as a nanomatrix for the catalysis of chemical denitrification yielding the generation of gaseous products from nitrite [59,60]. Secondly, they can contribute to the stabilization of foam structure [39,51].…”

Importance of extremophilic microorganisms in biogeochemical cycles

“…"Extremophilic microorganisms are organisms that thrive physically or geochemically in extreme conditions that are generally harmful to most life on Earth" [1]; such as very high or very low temperatures, high or low pH levels, high pressures, low availability of nutrients or high concentrations of salt. Extreme environments are defined as those environments or ecosystems that exceed the limits of the ranges of the physical-chemical environmental parameters suitable for most living beings [2,3].…”

“…Extreme environments are defined as those environments or ecosystems that exceed the limits of the ranges of the physical-chemical environmental parameters suitable for most living beings [2,3]. These ecosystems are cold polar lands and seas, alpine glaciers, underwater vents, saline lakes, hot springs, volcanic areas, ecosystems on the seabed or under the earth's crust (where pressure values are very high), among others [3,4] Extremophiles are found in the three domains of life: Archaea, Bacteria, and Eukarya; but most of the Extremophiles belong to the domain of Archaea [1]. In general, these organisms are classified according to the environmental conditions in which they grow optimally; thus we have: acidophiles (pH ≤3), alkaliphiles (pH ≥9), halophiles (high salt concentration), hyperthermophiles (temperatures> 80 ° C), thermophiles (temperature between 42-122 ° C), piezophiles (high pressures), psychrophiles (temperatures ≤-15 ° C), radiophiles (UV radiation, cosmic rays, X-rays) and xerophiles (drying conditions; ≤50% relative humidity) [1,5].…”