Are microbes the answer to the energy crisis?

Microscopic organisms could be the answer to the looming fuel crisis in the not too distant future.

These biological factories can turn out unlimited supplies of inexpensive, eco-friendly biofuels as an oil-substitute, according to a study.

Among alternative fuels, ethanol is the current king. Almost all ethanol produced in the US is fermented from readily available sugars in maize. Ethanol from maize has also been blamed for rising food prices.

The most attractive alternatives are known as lignocellulosic biomass and include wood residues (sawmill and paper mill discards), municipal paper waste, agricultural residues (sugarcane bagasse) and dedicated energy crops (like switchgrass).

The problem is, unlike corn, the sugars necessary for fermentation are trapped inside the lignocellulose.

Govind Nadathur and colleagues at the University of Puerto Rico have been looking at unusual ecosystems and unusual organisms to find enzymes to help extract these sugars.

"Wood falls into the ocean. It disappears. What's eating this biomass? We found molluscs that eat the wood, with the help of bacteria in their stomachs that produce enzymes that break down the cellulose.

"We found something similar in termites," says Nadathur. They plan on using these enzymes as a key step in a closed, integrated system that would not only produce ethanol, but would also produce sugar, molasses, hibiscus flowers and bio-diesel with a minimum of waste.

Another promising bio-fuel is hydrogen. Unfortunately, current chemical manufacturing processes for hydrogen are not that efficient or use fossil fuels as a source.

Sergei Markov of Austin Peay State University has developed a prototype bioreactor that uses the purple bacterium Rubrivivax gelatinosus to produce enough hydrogen to power a small motor.

Certain purple bacteria, which usually grow in the mud of various ponds and lakes, have the ability to convert water and carbon monoxide into hydrogen gas, though only a certain set could use carbon monoxide.

These findings were presented Wednesday at the 108th general meeting of the American Society for Microbiology in Boston.