Science: Penicillin Production

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Penicillin was still making news last week. In Britain, its discoverer and chief developer, Professors Alexander Fleming and Howard W. Florey (TIME, May 15), were knighted by King George VI. Sir Howard reported progress toward chemical synthesis of the drug. In the U.S. the available supply for civilians was doubled: penicillin was shipped to 1,000 more hospitals, including some in Alaska, Hawaii, Puerto Rico, the Virgin Islands. But the biggest news was on the production front. In May, U.S. plants made 100 billion units of penicillin — one-third more than in April and just 250 times as much as a year ago. A small army of biochemists and mycologists had contributed to this achievement. Last week their leader told how it was done. Dr. Robert D. Coghill, of the U.S. Agriculture Department's Northern Regional Research Laboratory in Peoria, Ill., addressing chemists in Manhattan, reported that new methods developed in his laboratory had speeded up the making of penicillin 150-fold. The huge effort concentrated on penicillin—hundreds of scientists, 21 manufacturers, $20,000,000 in plants—has been concerned with one major problem: how to make the mold that produces penicillin yield more heavily. This delicate process has more hazards than an obstacle race. The penicillium mold, found in fertile soil, is cultivated in a sugary solution. It develops a network of very fine branches, *called "mycelium," which secrete penicillin. If the delicate mycelium breaks, production of penicillin stops. Temperature must be kept at 24°C. Worst of all hazards is contamination. The sugary bath in which the mold grows is an ideal medium for bacteria; if any get in, they destroy all penicillin present in three hours. And when all these hazards are survived, the yield is fantastically small. The broth from which powdered penicillin is extracted contains only two to six thousandths of 1% of pure penicillin.

At first, penicillin was produced only in small flasks (relatively easy to protect against contamination) from a strain of the mold, Penicillium notatum. In Dr. Coghill's laboratory, mycologists developed new, heavier-yielding strains. They also found that the mold's growth could be greatly speeded in a brew of lactose made from skimmed milk and steep liquor made from corn.

But the biggest step forward was the development of a method of making penicillin in tanks instead of in flasks. The tank ("submerged") method has saved much labor, cut the minimum cycle of the mold's growth from six to three days, helped cut the price of penicillin nearly 85%. Present average costs of penicillin treatments: $35 for severe septicemia (1,000,000 units), $5 for gonorrhea (150,000 units).

Nonetheless, though authorities predicted in January that all needs for penicillin could be met by this month, production is still far behind demand. Reason: new uses for penicillin are being discovered faster than new methods of production.

*The fuzzy ends of these branches (see cut) gave penicillium its name, which comes from the Latin penicillus, meaning "brush" (forerunner of the modern pencil).