Kenneth Raper – Master of Molds

Born in 1908 to a family of eight children in North Carolina, Kenneth Bryan Raper was an American mycologist, microbiologist, and botanist. He contributed heavily to medical and industrial mycology and pioneered the study of Dictyostelium discoideum, a cellular slime mold.

Kenneth Raper completed his BA at the University of North Carolina, moving on to procure master’s degrees from George Washington University and Harvard University before obtaining a Ph.D. from Harvard in 1936. Raper began his career at the USDA Bureau of Chemistry and Soils, where he worked as a mycologist from 1929-1936, followed by contributions at the USDA Bureau of Plant Industry in Peoria, IL from 1936-1940. During his time at the Bureau of Plant Industry, Raper met Dr. Charles Thom, with whom he would eventually co-author A Manual of the Aspergilli (1945) and A Manual of the Penicillia (1949), two landmark texts in mycological studies.

Continuing to serve the USDA, Dr. Raper took a position in 1940 as a microbiologist at the Northern Regional Research Laboratory in Peoria, IL. Here he received a visit from British scientists who sought to develop a method for producing large amounts of penicillin, which was rationed at the time due to WWII. Along with his “Penicillin Team” at the NRRL, Raper developed a method for producing penicillin in submerged culture which greatly increased yields. This innovation had a critical effect on the war effort as it increased the amount of penicillin available for wound care.

In 1953, Raper left the USDA for a position as Professor of Bacteriology and Botany at the UW-Madison. Here, Raper pioneered research on the Dictyosteliaceae, including their life histories, cytology, and taxonomy. This work led to Ken Raper’s publication of his well-known text The Dictyostelids in 1984.

What’s in a name? The history of “Raper” as a surname

The surname Raper, of English origin, is derived from the pre-7th century word “rap”, meaning rope. A “raper” (“roper”) would be the medieval name for a rope maker, an important career both in medieval and modern times. The name Raper in some form has been documented since as early as the year 1220.

Douglas Gorsline's 1948 painting depicts Peoria, IL's "Moldy Mary"holding the cantaloupe that would contribute the most successful of over 100,000 strains of Penicillium cultured by Raper and his team.