Effects of Ionizing Radiation and Long-Term Storage on Hydrated vs. Dried Cell Samples of Extremophilic Microorganisms

A main factor hampering life in space is represented by high atomic number nuclei and energy (HZE) ions that constitute about 1% of the galactic cosmic rays. In the frame of the “STARLIFE” project, we accessed the Heavy Ion Medical Accelerator (HIMAC) facility of the National Institute of Radiological Sciences (NIRS) in Chiba, Japan. By means of this facility, the extremophilic species Haloterrigena hispanica and Parageobacillus thermantarcticus were irradiated with high LET ions (i.e., Fe, Ar, and He ions) at doses corresponding to long permanence in the space environment. The survivability of HZE-treated cells depended upon either the storage time and the hydration state during irradiation; indeed, dry samples were shown to be more resistant than hydrated ones. With particular regard to spores of the species P. thermantarcticus, they were the most resistant to irradiation in a water medium: an analysis of the changes in their biochemical fingerprinting during irradiation showed that, below the survivability threshold, the spores undergo to a germination-like process, while for higher doses, inactivation takes place as a consequence of the concomitant release of the core’s content and a loss of integrity of the main cellular components. Overall, the results reported here suggest that the selected extremophilic microorganisms could serve as biological model for space simulation and/or real space condition exposure, since they showed good resistance to ionizing radiation exposure and were able to resume cellular growth after long-term storage.

Industrial Applications of Enzymes From Extremophiles

Extremophilic microorganisms have developed a variety of molecular tactics to exist in extreme environments. Researchers are fascinated by extremophiles and unearth various enzymes from these fascinating microbes. Extremozymes are astonishing biocatalysts with distinctive properties of catalysis and stability under a multitude of daunting conditions of salt, pH, organic solvents, and temperature, which open up new possibilities for biocatalysis and biotransformation and outcompetes mesophilic counterparts. Biotechnological implications include simple, immobilized, as well as whole-cell applications. Stability in organic solvents adds to the asymmetric catalysis and thereby exemplifies the applicability of extremozymes and in fostering biobased economies. Marine, cold-adapted enzymes, and those that help in the removal of a toxic hazardous substance from the environment are obvious choices for food industries and bioremediation. The major area of application and research emphasis includes textile, detergents, food, dairy, agriculture, and environmental remediation.

Biochemistry Behind Protein Adaptations in Extremophiles

Extremophiles are the mortals that tolerate in the most limiting and aggravating conditions to life. Because of these fantastic ecological criticisms, extremophiles have substituted innumerable intriguing transformations to cell films, proteins, and extracellular metabolites. These stimulatingly regulated usual particles and frameworks as of now play parts in numerous biotechnological fields. Compounds from extremophilic microorganisms as a rule catalyse synthetic responses in non-standard conditions. Such conditions advance accumulation, precipitation, and denaturation, diminishing the movement of most non-extremophilic catalysts, regularly because of the shortfall of adequate hydration. Extremophilic catalysts can go after hydration by means of modifications particularly to their surface through more noteworthy surface charges and expanded sub-atomic movement. These assets have permitted few extremophilic compounds to work within the sight of non-fluid natural solvents, with potential for plan of valuable impetuses.

Genome Editing and CRISPR/Cas System of Extremophiles and Its Applications

Extremophiles will be the choice of next generation industrial biotechnology (NGIB) as they are known to be contaminant resistant, but engineering their genomes has always been difficult and time consuming task. CRIPR/Cas (clustered regularly interspaced short palindromic repeat and CRISPR associated proteins) system can be employed for this reason. The genome of an industrially important halophile (i.e., Halomonas) was edited to study a combined effect of four different genes on glucose breakdown and production of poly (3-hydroxybutyrate-co-3-hydroxyvalerate). This editing has resulted in 16-fold increase of 3HV, and the mutants generated by CRIPR/Cas system were significantly effective in synthesizing PHBV. Unfortunately, this system does not always work, specifically in extremophilic microorganisms because Cas9 or Cpf1 are from mesophilic bacteria. Therefore, alternatively, the endogenous CRISPR/Cas system is used for editing the genomes of such organisms. This genome editing of extremophiles will open the doors for developing next generation industrial biotechnology (NGIB).

Highly Stable, Cold-Active Aldehyde Dehydrogenase from the Marine Antarctic Flavobacterium sp. PL002

Stable aldehyde dehydrogenases (ALDH) from extremophilic microorganisms constitute efficient catalysts in biotechnologies. In search of active ALDHs at low temperatures and of these enzymes from cold-adapted microorganisms, we cloned and characterized a novel recombinant ALDH from the psychrotrophic Flavobacterium PL002 isolated from Antarctic seawater. The recombinant enzyme (F-ALDH) from this cold-adapted strain was obtained by cloning and expressing of the PL002 aldH gene (1506 bp) in Escherichia coli BL21(DE3). Phylogeny and structural analyses showed a high amino acid sequence identity (89%) with Flavobacterium frigidimaris ALDH and conservation of all active site residues. The purified F-ALDH by affinity chromatography was homotetrameric, preserving 80% activity at 4 °C for 18 days. F-ALDH used both NAD+ and NADP+ and a broad range of aliphatic and aromatic substrates, showing cofactor-dependent compensatory KM and kcat values and the highest catalytic efficiency (0.50 µM−1 s−1) for isovaleraldehyde. The enzyme was active in the 4–60 °C-temperature interval, with an optimal pH of 9.5, and a preference for NAD+-dependent reactions. Arrhenius plots of both NAD(P)+-dependent reactions indicated conformational changes occurring at 30 °C, with four(five)-fold lower activation energy at high temperatures. The high thermal stability and substrate-specific catalytic efficiency of this novel cold-active ALDH favoring aliphatic catalysis provided a promising catalyst for biotechnological and biosensing applications.

Shallow Hydrothermal Vent Bacteria and Their Secondary Metabolites with a Particular Focus on Bacillus

Extreme environments are hostile for most organisms, but such habitats represent suitable settings to be inhabited by specialized microorganisms. A marine shallow-water hydrothermal vent field is located offshore in northeast Taiwan, near the shallow shore of the southeast of Kueishantao Island (121°55′ E, 24°50′ N). Research on extremophilic microorganisms makes use of the biotechnological potential associated with such microorganisms and their cellular products. With the notion that extremophiles are capable of surviving in extreme environments, it is assumed that their metabolites are adapted to function optimally under such conditions. As extremophiles, they need specific culture conditions, and only a fraction of species from the original samples are recovered in culture. We used different non-selective and selective media to isolate bacterial species associated with the hydrothermal vent crab Xenograpsus testudinatus and the sediments of its habitat. The highest number of colonies was obtained from Zobell marine agar plates with an overall number of 29 genetically distinct isolates. 16sRNA gene sequencing using the Sanger sequencing method revealed that most of the bacterial species belonged to the phylum Firmicutes and the class Bacilli. The present study indicates that hydrothermal vent bacteria and their secondary metabolites may play an important role for the reconstruction of the evolutionary history of the phylum Procaryota.

Extremophilic Microorganisms in Central Europe

Extremophiles inhabit a wide variety of environments. Here we focus on extremophiles in moderate climates in central Europe, and particularly in Slovenia. Although multiple types of stress often occur in the same habitat, extremophiles are generally combined into groups according to the main stressor to which they are adapted. Several types of extremophiles, e.g., oligotrophs, are well represented and diverse in subsurface environments and karst regions. Psychrophiles thrive in ice caves and depressions with eternal snow and ice, with several globally distributed snow algae and psychrophilic bacteria that have been discovered in alpine glaciers. However, this area requires further research. Halophiles thrive in salterns while thermophiles inhabit thermal springs, although there is little data on such microorganisms in central Europe, despite many taxa being found globally. This review also includes the potential use of extremophiles in biotechnology and bioremediation applications.

Importance of extremophilic microorganisms in biogeochemical cycles

Extremophilic microorganisms are organisms capable of proliferating under extreme conditions that are generally detrimental to most life on Earth. They are organisms considered of importance in different areas of research, due to their ability to produce proteins and enzymes under inhospitable conditions. Therefore, in the present work, the information on their participation in the processes of biogeochemical cycles was collected and analyzed in order to demonstrate their ecological importance. Recent studies on the metabolic pathways of the Extremophilic microorganisms and their environment have shown that most of the archaea, some bacteria and cyanobacteria carry out metabolic activities essential for the biogeochemical cycles of sulfur, carbon and nitrogen. Archaea and bacteria being one of the main microorganisms that participate in a variety of processes such as sulfidogenesis, methanogenesis, ANAMMOX (anaerobic ammonium oxidation), among others. This has suggested that Extremophilic microorganisms and extreme ecosystems have a significant impact on global biogeochemical cycles.