Antibiotics are produced in laboratory conditions by fermenting microorganisms in tanks that hold hundreds of thousands of gallons, according to Infoplease from Pearson Education. Scientists strain the mold out of fermentation broth before the antibiotics are separated by filtration or precipitation. Antibiotics grow in nutrient-rich media under optimum conditions.
Some antibiotics are synthesized, while others are modified from natural sources. Synthetic antibiotics may be more effective to treat some infections because the body absorbs them more efficiently and bacteria strains could be less resistant to synthetic variations, notes Infoplease.
Actinomycetes offer scientists one natural source of antibiotics. These microorganisms grow in the soil, and scientists can mutate the genes of these bacteria to produce antibiotic properties that kill bacterial infections, according to the Center for Bioenergy & Photosynthesis at Arizona State University.
Actinomycetes, especially from the genus Streptomyces, have been used to produce antibiotics since the mid-1940s, as explained in class notes from the Botany Department at the University of Hawaii. Actinomycetes led to the discovery of streptomycin, the first antibiotic to fight tuberculosis.
New antibiotics are discovered by activating or deactivating genes of various microorganisms that have antibiotic properties, notes the Center for Bioenergy & Photosynthesis. Some genetic mutations produce stronger antibiotics while others do not. In the United States, such drugs must be thoroughly tested and certified before the FDA approves a new antibiotic.