Great Bugs of Fire - Volcano Loving Bugs

A volcano-loving bug offers clues as to what makes life possible in extreme conditions.

They may be small, but they're very hot. They're the archaea, an ancient branch of microbial life on Earth discovered by scientists in 1977. Unlike the better known bacteria and eukaryotes (plants and animals), many of the archaea can thrive in extreme environments like volcanic vents and acidic hot springs. They can live without sunlight or organic carbon as food, and instead survive on sulfur, hydrogen, and other materials that normal organisms can't metabolize. It may sound like science fiction, but many scientists are working rapidly to explore the biology as well as the practical benefits of these life forms.

An enzyme, alcohol dehydrogenase (ADH), is derived from a member of the archaea called Sulfolobus solfataricus. It works under some of nature's harshest volcanic conditions: It can survive to 88 deg. C (190 deg. F) - nearly boiling - and corrosive acid conditions (pH=3.5) approaching the sulfuric acid found in a car battery (pH=2). ADH catalyzes the conversion of alcohols and has considerable potential for biotechnology applications due to its stability under these extreme conditions. To understand how it works, scientists first need to learn its basic structure. For this, an Italian research team went to space.

After collecting Sulfolobus solfataricus from the Solfatara volcanic area near Naples, the Italian team used the ADH enzyme for crystallization aboard the Space Shuttle.

Compared to crystals grown in Earth's gravity, the space crystals showed an improved quality of nearly 35%, and the researchers obtained diffraction data with a significantly higher resolution, indicating reduced disorder. Scientists hope to use the space grown crystals to improve the biological understanding of how these molecules work based on a detailed knowledge of their shape and exact atomic positions.

A fundamental question posed by the space shuttle investigation is: what features of these volcanic microbes' metabolism allows for such thermal stability in their enzymes? If unusual characteristics in their metabolism can be identified and studied, the transfer of this knowledge is almost immediate to applications in environmental cleanup, pollution prevention, or energy production. Many researchers envision a range of medically, industrially, and environmentally useful compounds derived from the extreme heat-loving, or "hyperthermophilic" Archaea.