SYDNEY, 27 July 2006 – For the first time, an acid- and heat-loving micro-organism plucked from deep-sea hydrothermal vents has been grown in the laboratory, giving researchers vital clues to understanding the role they play in their peculiar environment.
“We can only grow about one to ten per cent of all the microbes from the environment”, said microbiologist Anna-Louise Reysenbach from the School of Biology at Portland State University, “so any time you grow an important player in an ecosystem, it is really significant, because by growing them in the lab we can tell something about what their function in the environment is.”
This acid and heat loving or ‘thermoacidophilic’ microbe, belongs to a bacterial group known as DHVE2. Dubbed Aciduliprofundum boonei by Reysenbach and her colleagues in this week’s edition of the journal Nature, they found that it thrives at pH values between 3.3 and 5.8 – similar acidity to vinegar. It can also withstand temperatures between 55˚C and 75˚C – enough to kill off most other organisms.
Previous cultures from the deep-sea vents had only revealed microbes that thrived in pH neutral conditions, despite the apparently acidic environment of the hydrothermal vents.
“The hydrothermal fluids at deep-sea vents are highly acidic,” said Reysenbach, “and models have predicted that acidic microhabitats are present in sulphide deposits, yet all microbes that have been isolated from these deposits grow near pH7 and are, at best, only tolerant of acid conditions.”
By growing this newly discovered organism in the laboratory, Reysenbach and colleagues have shown for the first time that acid loving microbes do indeed play a significant role in the sulphur, iron and carbon cycles at deep-sea vents.
Reysenbach explained how these results illustrate just how much remains to be discovered in microbial world. Acid or heat-loving microbes could have many applications in industry. They could potentially clean up spills or be involved in mining processes. Studies of these extreme environments also prepare scientists for their search for life elsewhere in the solar system.
“There are some microbes that grow at pH1 and 70˚C”, said Reysenbach. “If there is a place on Earth, or elsewhere in the solar system, where there is energy to tapped, microbes will figure a way to use it. They’re very resourceful.”