Features: Nov. 26, 2001

Researchers Study Unusual Bacteria

A rare group of microorganisms, which thrive in a harsh, sulfidic, oxygen-free environment, was known to exist only in New Zealand. But Rensselaer researchers may have found extensive amounts of it in several hot springs in the Philippines.

Their new research of what is collectively called thermophilic green sulfur bacteria could give a better glimpse into the beginning of life on Earth, when oxygen was virtually nonexistent on its surface. The research could also advance energy production and wastewater cleanup.

The low pH, high temperature, and high-sulfide content in the hot springs provide an ideal oxygen-free environment to study the type of photosynthesis that existed before oxygenic plants, the typical green plants we see today.

The bacteria feed themselves, or photosynthesize, by harnessing light to split hydrogen from sulfur-containing compounds and cannot tolerate oxygen.

In contrast, green plants photosynthesize by using light to split hydrogen from water. The hydrogen combines with carbon dioxide from the air. The leftover oxygen is released.

These sulfur bacteria could be used for wastewater treatment because they convert toxic sulfur compounds into harmless sulfur compounds. Since the bacteria are capable of producing hydrogen, they also could be used to generate alternative energy.

"These bacteria are potentially a window into the earliest environment of sustainable life and they are potentially useful for biotechnological applications," says Jun Abrajano, professor of earth and environmental sciences.

The Rensselaer research team has received a $100,000 grant from the National Science Foundation Biocomplexity Program to further explore the unique bacteria and to better understand their complex interactions with other bacteria and the surrounding environment. The team consists of Abrajano, Donna Bedard, research professor of biology, and Russell Manson, assistant professor of environmental engineering.