5 Extreme Bacteria That Survive in Extreme Environments

Extreme bacteria are certain microorganisms that can survive in extreme environments that would otherwise be lethal to other living beings. These extreme environments include extremely high or low temperatures, high salt concentrations, extreme pressure or pH levels, and even high radiation exposure. These bacteria possess special adaptations that enable them to thrive in such harsh conditions.

There are various types of extreme bacteria, categorized based on their ability to survive in specific environments. Extreme bacteria that can survive have special adaptations to survive in these extreme conditions. There are various types of extreme bacteria according to their ability to live in certain environments, including:

1. Thermophilic Bacteria

Thermophilic bacteria can withstand high-temperature environments. Their adaptation mechanisms include producing heat-resistant enzymes (such as DNA polymerase), saturated fatty acids to prevent membrane melting, and chaperone proteins that stabilize cellular proteins. 

2. Psychrophilic Bacteria

Psychrophilic bacteria, which survive in extremely low temperatures (-20°C to 10°C). Their adaptation mechanisms include unsaturated fatty acids to maintain membrane fluidity, antifreeze proteins to prevent ice crystal formation, and enzymes that remain active at low temperatures. 

3. Halophilic Bacteria

Additionally, halophilic bacteria can survive in high-salt environments, such as salt lakes and the Dead Sea. These bacteria adapt by accumulating potassium ions to maintain osmotic pressure and using acidic proteins that function well in high-salt conditions. 

4. Acidophilic Bacteria

Acidophilic bacteria maintain a neutral cytoplasmic pH through specialized ion pumps.

5. Alkaphilic Bacteria

Alkaliphilic bacteria utilize sodium ions for survival.

Read more:
What Are Extremophiles?

History of the Discovery of Thermophilic Bacteria

One fascinating type of extreme bacteria is thermophilic bacteria, which can survive in very high temperatures (above 45°C). An example of a thermophilic bacterium is Thermus aquaticus, a rod-shaped, Gram-negative bacterium without flagella (mobility structures). This bacterium was discovered by Thomas Brock, a renowned professor in microbial ecology, during his visit to Yellowstone National Park in July 1964. 

While observing the hot springs, Brock noticed unique color patterns on the water surface, forming temperature gradients as the hot water gradually cooled. To his amazement, he discovered microbial colonies thriving along these temperature gradients, with some found in water as hot as 80°C. Brock and his student Hudson Freeze analyzed the microbial samples from the hot springs. 

Their analysis revealed the presence of proteins but no chlorophyll (the main pigment for photosynthesis in photosynthetic microbes). They concluded that the organism was a bacterium and coined the term “hyperthermophile,” meaning an organism that loves extreme heat. They eventually isolated a new bacterium, Thermus aquaticus, which could survive at temperatures between 60°C and 80°C. 

This groundbreaking discovery challenged the scientific belief that life could not thrive in such extreme conditions. Since then, research on extremophiles has reshaped scientists' understanding of life’s origins, characteristics, and boundaries. It also demonstrated that living cells could adapt their metabolism to survive extreme environmental conditions.

How Does Thermus aquaticus Adapt to Extreme Environments?

Extremophilic bacteria have specialized protein adaptations that enable them to survive in extreme conditions. These proteins are designed to remain stable and functional in harsh environments but would degrade in mesophilic organisms (organisms that prefer moderate conditions).Thermophilic proteins possess strong hydrophobic interactions, which reduce the surface area exposed to solvents, thereby minimizing the risk of thermal denaturation. 

Additionally, thermophilic proteins have strong electrostatic interactions, with charged residues like arginine and lysine forming salt bridges that stabilize the tertiary structure of proteins at high temperatures. Shorter surface loops in thermophilic proteins also reduce flexibility, increasing structural stability in high-temperature conditions. Thermus aquaticus produces Taq DNA polymerase, an enzyme that remains stable and functional at high temperatures.

Due to its heat resistance, Taq polymerase became a critical component in the polymerase chain reaction (PCR) technique, which is widely used in molecular biology. The bacterial cell membrane of Thermus aquaticus contains saturated fatty acids, which increase membrane stability and integrity under high-temperature conditions. 

The bacterium’s unique metabolic adaptations allow it to obtain energy by absorbing organic compounds from its environment, often derived from other organisms’ excretions or the degradation of biomolecules.

Industrial Applications of Extremophiles

In addition to providing scientific insights, extremophiles have broad applications in industrial biotechnology. Enzymes produced by extremophiles, such as Taq polymerase from Thermus aquaticus and β-galactosidase from Halorubrum lacusprofundi, are used in various fields, including industrial processes, medicine, and environmental technologies. These enzymes remain effective under conditions that would typically destroy enzymes from ordinary organisms.

Moreover, certain molecules produced by extremophiles have therapeutic potential, including antibiotic, anticancer, and antioxidant properties, which are currently being studied for commercial development. Overall, extremophiles are a valuable resource for advancing the bio-based economy, inspiring new sustainable technologies in energy, environmental management, and healthcare. Their remarkable ability to survive in extreme conditions continues to push the boundaries of scientific research and industrial innovation.

By understanding the various types and mechanisms of extreme bacterial adaptation, we not only broaden our horizons about the limits of life, but also open up new opportunities in the use of biotechnology for the benefit of industry and health. Don't miss the next article which will discuss other interesting topics about microbiology and its applications in the world of industry and health. See you in the next article!

Author: Safira, Editor: Sabilla

References:

Aiyer, Kartik. 2023. How Extremophiles Push the Limits of Life. Tersedia: https://joyfulmicrobe.com/forensic-microbiology/, diakses pada 9 Januari 2025. 

Brock, T.D. 1967. “Life at High Temperatures.” Science. 

Cavicchioli, R. 2006. Cold-adapted enzymes. Current Opinion in Biotechnology. 

Milnepublishing.geneseo. 2025. Thermus aquaticus. Tersedia: https://milnepublishing.geneseo.edu/botany/chapter/thermus-aquaticus/, diakses pada 9 Januari 2025. 

Oren, A. 2011. “Thermophilic Halophiles: Biology and Adaptations.” Extremophiles.