Final answer:
The U.S. Army was interested in producing penicillin to effectively treat infections and save soldiers' lives during World War II.
Step-by-step explanation:
The U.S. Army was interested in producing penicillin because it proved to be a potent antimicrobial agent that could save millions of lives during World War II. Discovered by Alexander Fleming in 1928, penicillin's mass production and purification were eventually realized by Howard Florey and Ernst Chain. The antibiotic was especially important on the battlefront to treat infections that would have otherwise been deadly to soldiers. The push to produce penicillin in large quantities was a response to the urgent demand for effective medical treatments to keep the armed forces healthy.