Chinese scientists have cracked the biological codes of a heat-tolerant bacterial strain that feeds on crude oil, fueling hopes of future applications such as the cleanup of oil contamination.

 

Geobacillus thermodenirificans NG80-2, the bacterial strain, was isolated from an oil well in Dagang Oil Field in North China's Tianjin, and has been shown to grow at temperatures of 45-73 C with crude oil as the sole energy source.

 

Researchers at Nankai University in Tianjin, after almost three years of experimentation, have finally determined the genetic sequence of the bacterial strain and discovered its metabolic pathway.

 

"We identified the key enzyme that enables the bacterium to degrade long-chain alkanes, a chemical component of oil, to smaller molecules," said Wang Lei, a key researcher for the project.

 

"We also discovered a simple way to isolate the enzyme."

 

Wang and his colleagues found NG80-2 produced large amounts of a protein called LadA, which performs the first step in the degradation of long-chain alkanes.

 

Long-chain alkanes are used as lubricant and fuel oils. They are a component of heavy oil, usually more viscous and difficult to extract or remove than light oil, which consists of shorter-chain alkanes.

 

The research results were published in this week's US journal Proceedings of National Academy of Sciences online, and the scientists suggest in their report that the protein is an "ideal candidate" for treatment of environmental oil pollution.

 

The sequence analysis also suggests the bacterial strain can adapt to many different environmental conditions since it involves a versatile metabolic processes, adding to its potential for a variety of biotechnology applications.

 

Current microbial approaches to degradation of oil pollutants are of low efficiency, and mostly apply to light oil, according to Wang, professor and dean of TEDA School of Biological Sciences and Biotechnology at Nankai University.

 

"More importantly, they are used in a context where no definitive knowledge about how the bacteria works is available," he said. "With the identification of this protein, we can upgrade it or alter it to various applications and improve the efficiency of its performance."

 

The research team has started looking into the three-dimensional structure of the protein and tested it in a field experiment on oil pollutant degradation.

 

Wang believes a wider application of the protein could be realized in two to three years. In addition to cleaning oil spills, oil extraction is another potential field to explore, he added.

 

US Department of Energy data has shown that the microbial approach can improve oil extraction efficiency by 10 to 15 percent and sustain the development term of oil reserves by five to 10 years.

 

Science Daily, a Beijing-based newspaper, reported that pilot field experiments at Shengli Oil Field helped increase cumulative oil production by about 60,000 barrels by 2005.

 

But Han Xuegong, a retired professor at China National Petroleum Corporation Managers Training Institute, warns that laboratory success does not necessarily guarantee industrial usage. "Cost plays a crucial role," he said.

 

(China Daily March 20, 2007)