Jenefir D. Isbister, a microbiologist with an Alexandria-based government contractor, has been awarded the Congressional Science and Technology Award for her work in developing a process that provides "an attractive alternative for the control of . . . acid rain."

The award is presented annually to private-sector companies or individuals for "pioneering leadership and achievements in energy and environmental research and development" by the Congressional Caucus for Science and Technology.

Working with a team of other scientists from Atlantic Research Corp. over the past three years, Isbister genetically engineered a microbe that has been able to remove as much as 50 percent of the sulfur from coal. Environmentalists and government officials argue that the burning of coal by heavy industry is the major reason for the life-threateningly high acid level of lakes and soil in the Northeast United States and Canada. Burning coal emits sulfurous fumes into the environment, which are then returned to the earth in the form of "acid rain."

In presenting the award, Rep. Mervyn M. Dymally (D-Calif.), chairman of the caucus, said the significance of Isbister's achievement is in reducing the costs of "cleaning" coal of its sulfur before it is burned. So-called precombustion cleaning is one of three ways of reducing the effect on the environment; the others methods involve the use of low-sulfur coal and the filtering of sulfurous fumes as they leave a coal-burning plant.

Isbister and a colleague in the project, chemist Judith Kitchens, said in an interview that while the patented process presents a possible new avenue of business for Atlantic Research, several factors probably preclude the immediate marketability of the process. These include the high cost of coal relative to other fuels; the lack of stringent federal regulation reducing the permissible level of sulfur emitted from coal-burning plants, and the need for further research.

Isbister said the process grew in part out of the company's program to develop a coal-water fuel that is a low-cost alternative to traditional fuels used by heavy industry.

Isbister, who received her doctorate in microbiology from the University of Maryland, works in the tiny -- but increasingly important -- environmental research section of Atlantic Research. The company, once best known as a developer of small rockets for missile systems, has diversified in recent years into data communications, printing, aerospace and alternative energy sources. Last year, it was the sixth-largest publicly owned high-tech firm in the Washington area, with revenue of $176.1 million.