Developments to Watch
THIS ENZYME MAY MAKE OIL BURN CLEANER
Pending Clean Air Act amendments are pushing oil companies to reduce sulfur in refined petroleum products, the villain behind acid rain and smog. Conventional methods using inorganic catalysts are costly because they require high temperature and pressure. So Texaco Inc. is working with four-year-old, Houston-based Energy BioSystems Corp. on a way to sweeten--or desulfurize--oil before it reaches refineries. The sweetener is an enzyme that the bacterium Rhodococcus rhodochrous evolved to survive in the soil around coal deposits.
The Institute of Gas Technology isolated the family of bacteria in 1988 and licensed the technology to Energy BioSystems in 1991. Energy BioSystems has since sequenced the key genes. The bacteria-produced enzyme works at room temperature to break the bonds between carbon and sulfur atoms. Past attempts to use desulfurizing bacteria failed because they ate too much oil. These bacteria don't consume oil--they just produce enzymes. St. Louis-based Petrolite Corp. and Energy BioSystems plan to desulfurize 10 to 100 barrels of oil a day at a pilot plant by mid-1994 and hope to build a commercial plant by 1996. Meanwhile, Energy BioSystems and the Institute of Gas Technology are speeding up evolution by rearranging the bacteria's genes to turn up enzyme production.EDITED BY PETER COY