Marine bacteria energy sources studied

BERKELEY, Calif., Feb. 13 (UPI) -- U.S. marine scientists have made a surprising discovery involving proteorhodopsin -- the light-sensitive protein found in many marine bacteria.

Researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory and the University of California-Berkeley found that when the ability to respire oxygen is impaired, bacterium equipped with proteorhodopsin will switch to solar power to carry out vital life processes.

"Our research shows proteorhodopsin contributes to a bacterial cell's energy balance only under certain environmental conditions, namely when the cell's ability to respire has been impaired," said biophysicist Jan Liphardt. "By harvesting light, proteorhodopsin enables bacterial cells to supplement respiration as a cellular energy source. This ability to withstand oxygen deprivation probably explains why so many ocean bacteria express proteorhodopsin."

Liphardt said the solar power option represents a potentially significant boost for efforts to develop alternatives to fossil fuel energy sources. Microbes that can simultaneously harvest energy from several different sources might be better at producing biofuels than microbes utilizing only a single energy source.

The study, with Howard Hughes Medical Institute investigator Carlos Bustamante and graduate students Jessica Walter and Derek Greenfield, appears in the Proceedings of the National Academy of Sciences.