Discovering extremophilic microorganisms
An article by Professor Garabed Antranikian from the Institute of Technical Microbiology at Hamburg University of Technology.
Extremophiles are organisms that thrive under conditions that are regarded as hostile to humans. Such environments and habitats include hot springs with temperatures close to the boiling point of water, and the deep sea, where low temperatures are coupled with high water pressure. “Extreme” conditions may also mean excessive pH or salt content levels. Robust biocatalysts (enzymes) and microorganisms with unique and extraordinary properties, such as the ability to operate at temperatures of up to 130 °C or an extreme acidic pH level of 0, can therefore be used efficiently for applications in sustainable bioprocesses. Current bioinformatic approaches (genomics and metagenomics) and high-throughput screening methods (robotics) are used in intelligent screening strategies aimed at discovering and identifying novel industrial enzymes.
Transitioning to a sustainable circular bioeconomy requires cutting-edge technologies that will guarantee economic growth and eco-friendly trade. It will only be possible to switch from a fossil-based to a biological process if we take advantage of the opportunities to discover and use our planet’s microbial diversity in the aforementioned extreme habitats.
Use of robust catalytic processes
Making unusual biological systems available will contribute to resolving global challenges such as the use of natural resources, the supply of food, health, energy and the environment. Microorganisms that can survive under extreme conditions constitute a biotechnological treasure trove for efficient bioprocesses. This is because they manufacture a broad range of unique biocatalysts (extremozymes) that are active at extreme temperatures, pH levels, high salt content and solvent concentrations. This allows biomass, e.g. plants, to be effectively converted by enzymes into high-quality products such as basic chemicals, biomaterials, pharmaceuticals, foods, animal feed and biofuels, resulting in the development of a more environmentally friendly biobased industry.
Enzymes that break down carbohydrates can be of great interest when it comes to producing biofuels and chemicals at high temperatures. Second-generation biofuels are made in biorefineries using lignocellulosic materials such as agricultural or forestry residues. The biomass needs to be pretreated on account of the complex structure of the plant cell walls, which makes the polysaccharides (carbohydrates consisting of several sugar molecules bonded together) accessible for the enzymatic effect. Thermal pretreatment has the advantage of allowing thermally active enzymes to be used to break down any available polymers at the same time. Another well-known example of thermally active enzymes is the DNA polymerase, which is used in laboratories to copy and reproduce DNA through polymerase chain reaction (PCR), e.g. for the diagnosis of hereditary diseases. The discovery of this extremozyme has enormously accelerated the development of the life sciences.
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