from Ahmad Iskandar Bin Haji Mohd Taha, Rifat Zubair Ahmed, Taro Motoigi, Kentaro Watanabe, Norio Kurosawa and Hidetoshi Okuyama writing in Cold-Adapted Microorganisms:

Ever since Escherichia coli, which is a mesophilic bacterium, was found to adjust its membrane fluidity in a liquid crystalline state by modulating fatty acid composition and the designation of this process as homeoviscous or homeophasic adaptation, numerous analogous phenomena have been reported in cold-adapted bacteria [psychrophilic or psychrotrophic (psychrotolerant) bacteria]. Unsaturation, which includes the biosynthesis of monounsaturated or long-chain polyunsaturated fatty acids and branched fatty acids, and branched-chain formation are the most important types of fatty acid modulation in psychrophilic and psychrotrophic (psychrotolerant) bacteria. The distribution of these fatty acids is not restricted to cold-adapted microorganisms: rather, it appears to depend on bacterial diversity (Gram- positive or negative) and/or habitat (terrestrial or marine environment) than on temperature. Eicosapentaenoic acid, which has been detected only in marine Gram-negative bacteria, had been regarded to confer significant membrane fluidity in bacteria, but it is now considered that it may also have a function in antioxidation or membrane modulation by constraining membrane fluidity. The mode of fatty acid modulation is unlikely to differ between psychrophilic and psychrotrophic bacteria, which had narrower and wider growth temperature ranges, respectively. The sole difference seems to be higher capacity to modulate fatty acid composition in psychrotrophic bacteria than in psychrophilic bacteria.

Further reading: Cold-Adapted Microorganisms

from Katayama Taiki and Michiko Tanaka writing in Cold-Adapted Microorganisms:

Bacteria and fungi preserved for long periods at sub-zero temperatures in Alaskan and Siberian permafrost ice wedge were reactivated on agar by aerobic cultivation at 15°C. Culturable bacteria differed among ice samples, but several phylogenetic groups were closely related to those in other frozen environments. Incubation under controlled temperatures and the Arrhenius profiles of bacterial isolates from the Alaskan ice wedge indicated that they could grow at temperatures below 0°C without remarkable alterations in their cellular process. The novel ice wedge isolates, Glaciibacter superstes AHU1791T and Tomitella biformata AHU1821T, increased membrane fluidity at lower to subzero temperatures by modulating the fatty acid composition of the cytoplasmic membrane. Reactivating the non-culturable state of ice wedge isolates using resuscitation promoting factor (Rpf) and culturing melted ice wedge with Rpf provided indirect evidence that non-culturable bacteria exist within the ice wedge in situ. Bacteria in ice wedges can change their membrane fatty acid composition and/or structure to survive, but may then lose the ability to grow under laboratory conditions, as a final adaptation to long periods in a frozen natural environment.

Further reading: Cold-Adapted Microorganisms

from Kazuaki Yoshimune, Jun Kawamoto and Tatsuo Kurihara writing in Cold-Adapted Microorganisms:

This chapter primarily describes cold shock proteins (CSPs), which are induced in response to temperature downshift in both psychrophiles and mesophiles. These proteins are important for various cellular processes, including transcription, translation, protein synthesis and folding, and membrane functions, to maintain their viability under cold conditions. Here, the CSPs in psychrophilic and mesophilic microorganisms are represented on the basis of the results of proteome analyses. In particular, CSPs that were isolated from the Antarctic psychrophile Shewanella livingstonensis Ac10 are described in detail. A number of microorganisms induce molecular chaperones in response to the cold, although the majority of chaperones are induced as a result of heat shock. Chaperones with peptidyl prolyl cis-trans isomerase activity are often induced by cold to accelerate protein folding by interconverting the cis and trans isomers of proline imidic peptide bonds, and these cold shock chaperones are also discribed here. Cold adapted proteins often have higher flexibility as compared to mesophilic proteins. The features of cold adapted proteins are briefly described. Finally, the production of recombinant proteins in psychrophiles is shown to suggest a future application of psychrophiles.

Further reading: Cold-Adapted Microorganisms

from Yuichi Nogi writing in Cold-Adapted Microorganisms:

Psychrophilic microorganisms are extremophiles that are capable of growth and reproduction at low temperatures. They are present in marine environments, which occupy slightly more than 70% of Earth's surface, especially in the Arctic, Antarctica, and deep seas at temperatures lower than 15°C. Marine psychrophiles utilize a wide variety of metabolic pathways, including photosynthesis, chemoautotrophy, and heterotrophy. The deep-sea bacteria called psychropiezophiles "love" both high pressure and low temperature. Marine psychrophiles are characterized by lipid cell membranes chemically resistant to hardening in response to the cold. Most psychrophiles are Bacteria, and psychrophily is present in widely diverse microbial lineages within the broad groups of Alpha-, Beta-, Delta-, and Gammaproteobacteria and the Bacteroidetes phylum.

Further reading: Cold-Adapted Microorganisms

"This book collects the work of renowned researchers to provide chapters outlining the mechanisms Archaea, Bacteria and Eukarya use to survive extremes of temperature, pH, pressure and ionizing radiation. It focuses strongly on commercial applications ... recommended for senior undergraduates' independent reading or the reference of workers in the field alike" from Arwyn Edwards, Aberystwyth University, UK writing in Microbiology Today (2012) read more ...

Extremophiles: Microbiology and Biotechnology Edited by: Roberto Paul Anitori ISBN: 978-1-904455-98-1 Publisher: Caister Academic Press Publication Date: January 2012 Cover: hardback "recommended" Micro. Today

"a solid and critical review of the impact that extremophiles have in biotechnology. It discusses the adaptation of thermophilic, psychrophilic, acidophilic, and radiation-resistant microorganisms in their respective habitats ... the book offers newcomers to the biotechnology industry a good overview and a simple introduction to the subject, above all on future trends and web sources. " from Sonja Albers (Marburg) writing in BIOspektrum (2012) 18: 224. read more ...

Extremophiles: Microbiology and Biotechnology Edited by: Roberto Paul Anitori ISBN: 978-1-904455-98-1 Publisher: Caister Academic Press Publication Date: January 2012 Cover: hardback "a good overview" (Biospektrum)

from Mark Paul Taylor, Lonnie Van Zyl, Marla Tuffin and Don Cowan writing in Extremophiles: Microbiology and Biotechnology:

In principle, extremophiles have much to offer the biotechnology industry, from robust, process hardy enzymes to metabolically and physiologically diverse whole cell biocatalysts. However, the penetration of extremophilic organisms and their products into biotechnology markets has been modest at best, with preference given to engineered, cost effective enzyme variants and organisms for which established genetic tools are widely available. Interest in 'xtreme' products has often been dissuaded due to the unattractive need for the sometimes costly and complicated cultivation equipment and the complexities of culture maintenance. The lack of suitable genetic tools by which to improve, adapt or engineer a process involving an extremophilic host further complicates the issue. Legislative controls over national biological resources and allegations of biopiracy have also retarded commercialisation and industry-academia collaborations. However, commercial success stories have been described and form part of this review. Future prospects are optimistic, as several new biotechnology companies involved in the production of biomolecules from renewable resources have based their platform technology on extremophiles.

Further reading: Extremophiles: Microbiology and Biotechnology

from Hans Kristian Kotlar writing in Extremophiles: Microbiology and Biotechnology:

In the deep biosphere, extraordinary new types of microorganisms, sedimented or buried 200 - 500 million years ago, can be found. These organisms can be identified and characterized. The information obtained can be developed into novel tools for searching for new oil in sensitive regions like the Arctic, Antarctica and jungle areas. Relatively few enzymes are used in large-scale industrial applications. Enzymes isolated from these extremophile/ thermophile organisms might provide “game changing” new possibilities. They may furnish new incentives for the development of entirely new technical processes. These microbes provide opportunities for new technologies in second generation biofuel production. Several companies are working on alternative routes for the production of fuels using biomass as the raw source material. Traditional heavy oil extraction methods have major difficulties in justifying their high energy usage, CO₂ emissions and soil and environment pollution. The first company implementing a large-scale process based on biotechnology principles in enhanced oil recovery will gain huge strategic and economic benefits. The knowledge of this huge subsurface population of diverse microorganisms provides excellent opportunities for bioprospecting. There should be a multitude of spin-offs outside the oil industry. The world is desperately in need of new enzymes, new antibiotics, new immunosuppressant, new anticancer agents, etc. This chapter reviews just some of the areas we have been working on at Statoil. Hopefully some of these investigations could one day solve some of the problems we will face in the future. One day these extremophiles could be on the payroll of many different companies.

Further reading: Extremophiles: Microbiology and Biotechnology

from Helena Nevalainen, Ron Bradner, Sania Wadud, Suja Mohammed, Christopher McRae and Junior Te'o writing in Extremophiles: Microbiology and Biotechnology:

Fungi are eukaryotic organisms and considered to be less adaptable to extreme environments when compared to bacteria. While there are no thermophilic microfungi in a strict sense, some fungi have adapted to life in the cold. Cold-active microfungi have been isolated from the Antarctic and their enzyme activities explored with a view to finding new candidates for industrial use. On another front, environmental pollution by petroleum products in the Antarctic has led to a search for, and the subsequent discovery of, fungal isolates capable of degrading hydrocarbons. The work has paved the way to developing a bioremedial approach to containing this type of contamination in cold climates. Here we discuss our efforts to map the capability of Antarctic microfungi to degrade oil and also introduce a novel cold-active fungal lipase enzyme.

Further reading: Extremophiles: Microbiology and Biotechnology

from T.A. Vishnivetskaya, B. Raman, T.J. Phelps, M. Podar and J.G. Elkins writing in Extremophiles: Microbiology and Biotechnology:

Conversion of lignocellulosic biomass to liquid fuels using biological processes offers a potential solution to partially offset the world's dependence on fossil fuels for energy. In nature, decomposition of organic plant biomass is brought about by the combined action of several interacting microorganisms existing in complex communities. Bioprospecting in natural environments with high cellulolytic activity (for example, thermal springs) may yield novel cellulolytic microorganisms and enzymes with elevated rates of biomass hydrolysis for use in industrial biofuel production. In this chapter, various cellulose-degrading microorganisms (in particular, thermophilic anaerobic bacteria), their hydrolytic enzymes, and recent developments in the application of biomass fermentations for production of sustainable bioenergy are reviewed. In this context, results from ongoing research at the Oak Ridge National Laboratory in the isolation and subsequent phylogenetic and metabolic characterization of thermophilic, anaerobic, cellulolytic bacteria from the hot springs of Yellowstone National Park are presented.

Further reading: Extremophiles: Microbiology and Biotechnology

from Kazem Kashefi writing in Extremophiles: Microbiology and Biotechnology:

The isolation and characterization of novel hyperthermophilic, microorganisms from modern hot environments have greatly increased our understanding of how microbes can live and thrive in such inhospitable environments. The finding that microorganisms have the ability to grow at these high temperature has implications for delimiting when and where life might have evolved on a hot, early Earth; the depth to which life exists in the Earth's subsurface; and the potential for life in hot, extraterrestrial environments. The study of hyperthermophilic microorganisms provides valuable insights into microbial respiration in a diversity of modern and ancient hydrothermal systems. In addition, it provides information about the fate of metals such as iron, uranium, technetium, and even gold. Reduction of these metals by hyperthermophiles provides, for example, a likely explanation for a number of geologically, environmentally and economically important ore deposits. This allows us to identify geological signatures for biological processes, something that may prove instrumental in our search for life on other planets. Finally, enzymes capable of functioning at high temperatures have a number of important applications in biomass conversion, in biotechnology, and in the pharmaceutical, food and cosmetic industries.

Further reading: Extremophiles: Microbiology and Biotechnology

from Kelley R. Gwin and John R. Battista writing in Extremophiles: Microbiology and Biotechnology:

Of all the phenotypes associated with microorganisms, ionizing radiation resistance - the ability to survive exposure to high dose gamma radiation - is perhaps the most difficult to rationalize in terms of the natural world. There is no obvious selective advantage to being ionizing radiation resistant on Earth, as average yearly exposures to ionizing radiation from cosmic rays and radioactive decay are extremely low. Yet a significant number of genera exhibit this characteristic, displaying a remarkable capacity to tolerate levels of damage to cellular macromolecules that eradicates other forms of life. We argue that ionizing radiation resistance is an incidental characteristic, an inadvertent consequence of an evolutionary path that permitted these species to survive a selective pressure capable of damaging the cell in a manner similar to that of ionizing radiation. The phylogenetic distribution of ionizing radiation resistant species argues that these events occurred multiple times during the evolution of the Bacteria and Archaea, suggesting that different mechanisms may mediate ionizing radiation resistance.

Further reading: Extremophiles: Microbiology and Biotechnology

from Elizaveta Bonch-Osmolovskaya writing in Extremophiles: Microbiology and Biotechnology:

Thermophilic microorganisms, though known since the beginning of the 20th century, were intensively studied in its last three decades. Natural terrestrial and submarine thermal environments were found to be populated by moderate, extreme and hyperthermophilic microorganisms representing diverse metabolic groups. However, during the past few years this knowledge has been extended, and new metabolic groups of thermophilic prokaryotes described. Among these are ammonia-oxidizing archaea, thermoacidophilic methanotrophs of the phylum Verrucomicrobia, microorganisms gaining energy for growth from the disproportionation of sulfur species, and archaea and bacteria metabolizing one carbon (C1) compounds. Other novel metabolic groups, such as thermophilic anammox bacteria, nitrite-oxidizing thermophiles, and microorganisms performing anaerobic methane oxidation in thermal ecosystems, have been detected using molecular or geochemical approaches. These data will, certainly, stimulate further cultivation and isolation efforts.

Further reading: Extremophiles: Microbiology and Biotechnology

from Chiaki Kato writing in Extremophiles: Microbiology and Biotechnology:

Piezophilic microorganisms, which are defined as "pressure-loving" microorganisms, are isolated and characterized from high pressure environments. They grow better at high-hydrostatic pressures than at atmospheric pressures, and only exist at deeper water column environments, particularly in the deep-sea bottoms. Therefore, piezophilic microorganisms are typical deep-sea microorganisms that are well adapted to deep-sea pressure and temperature conditions. These microorganisms have special strategies for surviving in such extreme environments, where gene expression and enzyme activities could be controlled by pressure. Studies on adaptations to high pressure environments have recently been studied in detail, and the mechanisms involved are being elucidated. In this chapter, the distribution, taxonomy, cultivation and molecular characters of piezophiles are described.

Further reading: Extremophiles: Microbiology and Biotechnology

from Mark Dopson writing in Extremophiles: Microbiology and Biotechnology:

Acidophilic microorganisms are capable of growth at low pH and are defined as having an optimum below pH 5, with some extreme acidophiles capable of growth at pH 0. Acidophiles have an important role in ecology by catalyzing the generation of acidic, metal-containing solutions that can inhibit plant and animal growth, and in biotechnology via their propensity to solubilize metals from sulfide minerals. This review summarizes the most important aspects of acidophile physiology, including growth substrates (e.g. inorganic and organic carbon) and energy sources; temperature optima (from cold environments to high temperature thermal pools); and adaptations to metals in solution and low growth pH. The exploitation of acidophiles in biotechnology (e.g. in biomining) and potential future trends in research are also discussed. Due to a lack of general genetic systems in acidophiles, much of the latest research has been generated by systems biology approaches and these data have been focused upon.

Further reading: Extremophiles: Microbiology and Biotechnology

from Corien Bakermans writing in Extremophiles: Microbiology and Biotechnology:

Psychrophilic, or cold-loving, organisms actively live at low temperatures. Psychrophily is not an uncommon trait; cold-adapted organisms are found throughout the three domains of life and successfully inhabit a wide variety of low temperature environments. The ongoing investigation of these environments continues to broaden our view of what is possible for life on Earth. Cold-adapted microorganisms have evolved mechanisms to deal with the thermodynamic constraints of low temperatures. To combat the stability and decreased flexibility of macromolecules, psychrophiles generally increase the disorder within macromolecules to maintain fluidity or flexibility and hence function at low temperatures. To contend with reduced water activity and the presence of ice crystals, cryoprotectants are produced. To counteract decreased reaction and diffusion rates, psychrophiles practice efficient growth. Currently, the functional low-temperature limits of psychrophiles are minus 12 degrees celsius for reproduction and minus 20 degrees celsius for metabolism. The availability of liquid water appears to be the major growth-limiting factor at subzero temperatures. Examination of molecular and physiological adaptations to low temperatures is increasing our comprehension and appreciation of the capabilities of psychrophiles and their contribution to nutrient cycling in low temperature environments.

Further reading: Extremophiles: Microbiology and Biotechnology

from Christine Moissl-Eichinger, Ruth Henneberger and Robert Huber writing in Extremophiles: Microbiology and Biotechnology:

The SM1 euryarchaeon represents an extraordinary microorganism: in the surface waters of cold, sulfidic springs, it lives together with filamentous bacteria, forming the so called string-of-pearls community. In the subsurface however, it can grow partner-independently as a "monospecies" biofilm. Even though the SM1 euryarchaeon is still uncultivated in the laboratory, it is accessible via an in situ cultivation technique using its own biotope as a natural chemostat. This approach allowed the study of its biology, and enabled the discovery of unique cell surface appendices with unexpected and unusually high complexity. Each of the archaeal cells is surrounded by approximately 100 protein filaments that are up to 3 micrometres long and show a high resemblance to barbwire with a tripartite grappling hook at their tip. Based on this structure the appendices were called "hami" (lat. hamus = (grappling) hook). These hami represent perfectly evolved, natural mechanical nano-tools that could find applications in the growing field of nanobiotechnology.

Further reading: Extremophiles: Microbiology and Biotechnology