To help it catalyze methane

Mar 25, 2010 07:28 GMT  ·  By

Microbiologists are in awe, after the discovery of a new species of bacteria that can apparently synthesize its own oxygen. The microorganism actually thrives on methane, as it lives in a very specific layer of mud at the bottom of lakes and other bodies of water, where the hydrocarbon abounds, but oxygen is nearly inexistent. The bacteria, provisionally called Methylomirabilis oxyfera, hints at the fact that life on Earth may have developed without plants in its earliest days, and also that similar forms of organisms may exist on other planets, where oxygen is lacking as well, Nature News reports.

“The mechanism we have now discovered shows that, long ago, these organisms could have exploited the methane sources on Earth and possibly on other planets and moons by mechanisms that we didn't know existed,” explains microbiologist Mike Jetten, who holds an appointment at the Radboud University Nijmegen, in the Netherlands. He was also a member of the research group that discovered M. oxyfera. Details of their investigation appear in the latest issue of the esteemed scientific publication Nature. The expert says that the oxygen the bacteria produces is then consumed by its creator, so that the bacteria becomes capable of synthesizing methane.

The scientists in charge of the research were able to establish that these lifeforms thrived on methane and nitrogen oxides. Their diets include nitrites and nitrates, which nowadays can be found in larger concentrations at the bottom of waters that have been contaminated by agricultural residues. The fact that M. oxyfera is capable of producing oxygen from these chemicals adds the fourth method for doing this ever discovered in nature. The other three are photosynthesis (the process through which trees consume carbon dioxide to produce oxygen), reduction of chlorates in bacteria, and the enzymatic conversion of reactive oxygen species.

“It's a very unusual form of metabolism in that it's not directly utilizing oxygen from photosynthesis. It's an anaerobic form of metabolism at heart that then produces oxygen and becomes an aerobic form of metabolism,” says University of California in Santa Barbara (UCSB) geomicrobiologist David Valentine, a researcher unaffiliated with the new investigation. “It was very paradoxical. We found that they did have all the pathways that are necessary for living with oxygen, although they never see any oxygen, at least in our culture,” says RUN microbiology PhD student Katharina Ettwig. She was also one of the authors of the journal entry.