Investigating life in extreme environments may yield applications in the bioeconomy

From the deepest seafloor to the highest mountain, from the hottest region to the cold Antarctic plateau, environments labelled as 'extreme' are numerous on Earth and they present a wide variety of life-forms, with unique features and characteristics.

Investigating life processes in such extreme environments not only can provide hints on how life first appeared and survived on Earth, it can also give indications for the search for life on other planets. Importantly, the understanding of how organisms tolerate and adapt to extreme conditions and ecosystems may help to predict the impacts of current and future global change on biodiversity. Finally, the study of extreme life-forms - called 'extremophiles' - finds many applications in industry, in particular in the emerging bioeconomy and in biotechnology.

Unique enzymes, genes and metabolic processes found in micro-algae or bacteria may lead to new and highly efficient processes for the production of liquid biofuels, biogas or biohydrogen (recent examples are enzymes and genetic info from Sulfolobus solfataricus and Syntrophus aciditrophicus); properties of plants that survive in extreme environments may help in the design of new (energy) crops that are tolerant to drought, saline soils, frost or toxic environments; new phyto- and bioremediation systems may be created based on findings from research on extremophiles; and new products - from medicines and eco-friendly detergents to bioplastics and green polymers - are expected to emerge from unlocking the mysteries of how organisms cope in extreme conditions.

To examine these issues, the European Science Foundation (ESF) announces it has published a 58-page report entitled 'Investigating Life in Extreme Environments – A European Perspective' [*.pdf]. The report looks at how global changes in recent decades have turned some environments into becoming 'extreme' compared to the 'normal' ecosystems they used to be (e.g. acidification of the oceans). It analyses what kind of environments may become extreme in the future, and what this can teach us about the past, both here on Earth as on other planets. The report further looked at the range of useful applications that may be expected from research into extremophiles. Most importantly, the document outlines proposals for a new research framework that will boost scientific activities in this exciting field.

'Investigating Life in Extreme Environments' resulted from an interdisciplinary ESF inter-committee initiative which considered all types of life forms (from microbes to humans) evolving in a wide range of extreme environments (from deep sea to acidic rivers, polar regions and extra-terrestrial planetary bodies). The initiative held a series of consultations amongst Europe's science institutions in order to find out which type of extreme-environment research they see as most interesting, deserving priority and European funding:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: extremophiles :: microbiology :: genomics :: biotechnology :: energy crops :: bioeconomy :: European Science Foundation ::

On the basis of these consultations and two a large-scale interdisciplinary workshops (November 2005 and March 2006), scientists from across Europe issued a series of recommendations for further research, cooperation and funding. They look as follows:

Cross-cutting Scientific Recommendations

• Identify and agree on i) model organisms in different phyla (a group that has a genetic relationship) and for different extreme environments; and ii) model extreme environments
• Favour an ecosystem-based multidisciplinary approach when considering scientific activities in extreme environments.
• Foster the use of Molecular Structural Biology and Genomics when considering life processes in extreme environments

Cross-cutting Technology Recommendations

• Laboratory simulation techniques and facilities (e.g. microcosms) should be wider developed and made available to the scientific community.
• Develop of in-situ sampling, measurement and monitoring technologies. The assessment and use of existing techniques is also recommended.
• Adopt a common approach (specific to research activities in extreme environments) on technology requirements, availability and development.

Structuring and Networking the Science community

• Favorise interdisciplinarity and multidisciplinarity approaches between scientific domains and between the technological and scientific spheres.
• Create as soon as possible an overarching interdisciplinary group of experts to define the necessary actions to build a critical European mass in the field of “Investigating Life in Extreme Environments”
• Improve the information exchange, coordination and networking of the European community involved in scientific activities in extreme environments.

The report further includes recommendations specific to (1) Microbial life, (2) Life Strategies of plants, (3) Life Strategies of animals and (4) Human adaptation to extreme environments.

Benefits from research into extremophilic organisms
Organisms that live in extreme physico-chemical conditions, in high concentrations of deleterious substances or heavy metals, represent one of the most important frontiers for the development of new biotechnological applications. Actually, the biotechnological applications of extremophiles and their components (e.g. extremozymes) have been the main driving force for the research in this area.

The most direct application of extremophiles in biotechnological processes involves the organisms themselves. Among the most established we can find biomining, in which microbial consortia that operate at acidic pH are used to extract metals from minerals. Similar applications may help in enhancing oil recovery to obtain more petroleum from fields than would be possible by traditional pumping techniques.

Most applications involving extremophiles are based on their biomolecules (primarily enzymes, but also other components such as proteins, lipids or small molecules). The best-known example of a successful application of an extremophile product is Taq DNA polymerase from the bacteria Thermus aquaticus which facilitated a revolution in molecular biology methodology, but also other commercialised products (e.g. ligases, proteases, phosphatases, cellulases or bacteriorhodopsin) have resulted from investigation of extremophiles isolated from different environments.

In order to develop biotechnological processes, it is important to isolate the organism. In addition, the use of new methodologies, such as comparative genomics is helping to sort out the genetic and molecular bases of adaptation to extreme conditions, facilitating the design of improved products by the introduction of appropriate modifications by protein engineering. This approach has been used not only for improving the thermostability of enzymes but to design cryoenzymes for the food industry to operate at low temperatures.

Most microbial communities are complex and currently only a few components can be cultured. Sequence-based approaches to study the metabolism of microbial communities are being used to retrieve genomic information from the community of potential use in biotechnology (metagenomics). Strategies based on the generation of environmental genomic libraries have been developed to directly identify enzymes from the environment with the required specificity or the appropriate operational conditions.

Plants adapted to extreme environments also provide potential economic and societal applications. Extremophilic plants can survive under conditions toxic or harmful to crop plants. Therefore there is the potential to transfer, e.g. by molecular cloning, some of these abilities from extremophiles to crop plants with the aim of producing frost, salt, heavy metal or drought tolerance or enhanced UV stability. Plants can also be useful to remediate polluted areas where life is made difficult or impossible. New energy crops for the production of so-called 'third generation biofuels' offer a field of applications as well. ('Third generation biofuels' are called that way because they rely on crops the properties of which have been engineered in such a way that they match the demands of a specific bioconversion process; e.g. tree crops with low-lignin content, which makes them easier to pulp or to break down for the production of biofuels, have already been developed).

Phytoremediation is an innovative technology that uses the natural properties of plants in engineered systems to remediate hazardous waste sites. Within the phytoremediation technologies, phytoextraction (uptake and concentration of substances from the environment into plant biomass) and phytotransformation (chemical modification of environmental substances as a direct result of plant metabolism) are of applicative interest. Phytoremediation has been effectively used for the decontamination of soils and waters polluted by high concentrations of hazardous organic (e.g. pesticides) or inorganic (e.g. arsenic and mercury) substances. It is also a promising technology for the remediation of atmospheric pollutants (hydrocarbons, ozone). (See also how energy crops can be used for phytoremediation purposes - previous post on phytoremediation of coal-bed methane, on turning brownfields into green fields with energy crops, and more here and here).

Biomedical applications of adaptive mechanisms of animals should also be thoroughly investigated. Such potentialities are real as illustrated by the subantarctic King penguin that has developed the ability to preserve fish in its stomach for three weeks at a temperature of 38°C. With further developments, the antimicrobial and antifungal peptide involved in this conservation process might be used, for example, to fight some nosocomial infections.

In short, extremophile and extreme environment research is an emerging science field working in vast unexplored settings, and may open a whole range of applications beneficial to society.


The 'Investigating Life in Extreme Environments' document was published by the ESF, and its Marine Board (MB-ESF), the European Polar Board (EPB), the European Space Science Committee (ESSC), the Life Earth and Environmental Sciences Standing Committee (LESC), the Standing Committee for Humanities (SCH) and the European Medical Research Councils (EMRC).

References:
European Science Foundation: Investigating Life in Extreme Environments – A European Perspective [*.pdf] - July 2007.

European Science Foundation: Investigating Life in Extreme Environments report gives hints on life - July 4, 2007.