Oil Eaters

During a vacation two years ago at the popular Mediterranean beach of Tel Baruch, Israeli Professor Eugene Rosenberg discovered that no matter where he and his family went on the shore, their feet were continually blackened by globs of oil. Returning to Tel Aviv University, where he heads the microbiology department, Rosenberg angrily told an associate about the pollution. "It's a disgrace," he said. "Let's clean up those beaches." Since then, a university team under Rosenberg has developed a way of preserving not only beaches, but the oceans as well. The secret: oil-eating bugs.

With Biochemist David Gutnick, Rosenberg isolated a genus of bacteria called arthrobacter, which feast on crude oil, and then developed a particularly fast-multiplying new strain, which they named "RAG-1."* Bred in salt water enriched with phosphorus and nitrogen compounds, the strain gobbles up the paraffin (waxy) content of crude oil, leaving only small droplets of dewaxed oil that break down quickly in nature and become harmless carbon dioxide and water.

With their new strain, the Israeli scientists were able to begin an attack on the major direct cause of the world's oil pollution, which, contrary to popular belief, is not accidental spillage or the breakup of supertankers like Torrey Canyon. Most of this pollution is actually caused by routine tanker operations. Before entering harbor to take on a new load of crude oil, sea water used as ballast on the return trip is flushed into the ocean; it includes a small amount of crude oil (usually about one-half of 1% of the tanker's capacity) left over from the previous load. In this manner, the world's tanker fleets annually dump an estimated 1,000,000 tons of oil residue into the oceans.

No Slick. Going to the source of the problem, Rosenberg and Gutnick last winter boarded a 125,000-ton tanker to give RAG1 a practical test. Selecting two of the ship's tanks, which were each filled with 100 tons of sea water, they poured 55 lbs. of nitrogen-containing urea and 2.2 lbs. of potassium phosphates into each. Shipboard compressors were used to bubble air into the tanks through a perforated hose, thus turning them into ideal "bacterial fermenters," says Rosenberg. Then a flaskful of RAG1 bacteria was poured into one tank. Six and a half days later, the tanker discharged its ballast. The unbugged tank emitted an ugly black slick. But there was hardly any slick from the other tank; the bacteria had multiplied and taken the polluting elements out of the oil.

The result of the experiment is good news to shipowners. For one thing, none of the nutrient ingredients are expensive. For another, the bacteria do their work so well that tanks would not have to be washed and scraped when ships put in for periodic repairs. This is especially important because the scrubbing is done with high-pressure hoses; the nozzles sometimes develop charges of static electricity that can ignite oil fumes lingering in the tanks. Moreover, Rosenberg believes that his bugs may turn even the ballast water into profit. He figures that after the bacteria have cleaned the tanks in a 200,000-ton supertanker, the ballast could yield some 200 tons of dewaxed oil (which can be made into gasoline and other petroleum products). Beyond that, they can be harvested to produce about 150 tons of high-quality animal food.

Best of all, RAG1 cannot harm other life in the ocean. "We took the bacteria from nature," says Gutnick. "They are there and they are fastidious about what they like and do not like." When the bacteria run out of oil, they conveniently die and are themselves eaten by fish.

*An acronym for the names of the researchers:

Rosenberg, Avraham Reisfield and Gutnick.

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