# Fermentation Products in Pharmacy > Fermentation products in Pharmacy: penicillin and streptomycin organisms, media design, submerged culture, downstream processing and biotransformation. - Canonical URL: https://prepelephant.com/topics/allied/pharmacy/fermentation-products-pharmacy - Exam / course: Allied Health · Subject: Pharmacy - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Fermentation Products in Pharmacy", PrepElephant, https://prepelephant.com/topics/allied/pharmacy/fermentation-products-pharmacy ## Direct answer Fermentation products are medicines and pharmaceutical intermediates made by cultivating microorganisms in nutrient media and harvesting their metabolites — a technology supplying antibiotics (penicillin from Penicillium chrysogenum, streptomycin from Streptomyces griseus, tetracyclines), vitamins, enzymes, amino acids, microbially transformed steroids and alcohol. The industrial logic runs through media design (carbon sources such as glucose, lactose or molasses; nitrogen sources such as corn steep liquor; minerals and precursors), fermentation modes (batch, fed-batch for substrate-controlled products, continuous), operation (submerged culture in stirred, aerated bioreactors, or solid-state fermentation), control (temperature, pH, dissolved oxygen, sterility) and downstream processing — filtration of broth, solvent extraction or ion-exchange, concentration, crystallisation. Steroid biotransformation is the classic demonstration that microbes act as selective reagents: Rhizopus species introducing the 11-alpha hydroxyl onto progesterone transformed corticosteroid economics. ## What you must remember - **Historical anchors:** Fleming's 1928 Penicillium notatum observation; the 1940s Peoria programme where P. chrysogenum, corn steep liquor and lactose multiplied yields and deep-tank submerged culture industrialised production; Waksman's streptomycin from S. griseus in 1943 (Nobel 1952) opening the actinomycete era. - **Media components:** carbon (glucose, lactose feeding penicillin slowly, sucrose, molasses), nitrogen (corn steep liquor, soybean meal, ammonium salts), minerals, and precursors — phenylacetic acid feeding benzylpenicillin's side chain. - **Fermentation types:** batch, fed-batch (the industrial standard for antibiotics, holding carbon feed low to favour secondary metabolism) and continuous; growth-associated primary versus idiophasic secondary metabolites — antibiotics are secondary. - **Bioreactor essentials:** stirred tank with aeration and agitation, temperature and pH control, dissolved oxygen as the critical parameter, strict sterility throughout (one contaminant ruins weeks of batch). - **Downstream processing:** broth filtration, solvent extraction (penicillin into solvent at acid pH) or ion exchange, carbon decolourisation, concentration, crystallisation as sodium or potassium salts, drying, pharmacopoeial quality control. - **Biotransformation showcase:** Rhizopus 11-alpha hydroxylation of progesterone — the Upjohn breakthrough enabling cortisone and hydrocortisone routes — chemistry ordinary synthesis could not perform selectively. - **Product families:** antibiotics; vitamin B12 (Propionibacterium, Pseudomonas species); lysine by Corynebacterium glutamicum; citric acid by Aspergillus niger; enzymes including penicillin acylase, which builds semi-synthetic penicillins; dextran for plasma expanders; ethanol. - **Pharmaceutical connection:** 6-aminopenicillanic acid from penicillin G by acylase is the nucleus for ampicillin and amoxicillin; fermentation plants run under the same Schedule M GMP documentation and validation as any pharmaceutical unit. ## The life of one penicillin batch A production strain of Penicillium chrysogenum, preserved as a working culture, is grown through flask and seed-tank stages until vigorous enough to seed the main fermenter — a stirred, aerated tank of tens of thousands of litres of sterile medium. Carbon feeding is the artistry: lactose or slowly metered glucose keeps growth in check and pushes the mould into the secondary-metabolite phase, while phenylacetic acid feeds the side chain so the product is benzylpenicillin specifically; pH holds near neutral, and dissolved oxygen is never allowed to sag because the mould is strictly aerobic. After days of fed-batch running, the broth is harvested: filtration removes mycelium, the filtrate is acidified and penicillin extracted into solvent, back-extracted, carbon-treated, concentrated and crystallised as a salt, the whole train chilled because penicillin is unstable in aqueous acid. From strain preservation to crystallisation, every stage is documented, validated and inspected. ## How the exam separates students The dependable marks sit in organism-product pairs: penicillin with Penicillium chrysogenum, streptomycin with Streptomyces griseus, vitamin B12 with bacterial producers, citric acid with Aspergillus niger, dextran with Leuconostoc — swapping Streptomyces into penicillin loses the whole table. The second discriminator is fed-batch reasoning: antibiotics are secondary metabolites made after growth slows, so unrestricted glucose drives growth and represses product — the counterintuitive point vivas are built around. Third, downstream processing answered as "purification" alone earns little; the chain worth marks is filtration, extraction or ion exchange, decolourisation, concentration, crystallisation and drying, with acid-pH solvent extraction of penicillin the classic worked example. Finally, the biotransformation question deserves its history: Rhizopus 11-alpha hydroxylation of progesterone made corticosteroids affordable where chemistry could not install that oxygen selectively — one sentence connecting microbiology to every hydrocortisone tube in the pharmacy. ## Frequently asked questions ### Which organisms produce the classic antibiotics? Penicillium chrysogenum produces benzylpenicillin, Streptomyces griseus produces streptomycin, with actinomycetes broadly yielding the streptomycin, tetracycline and erythromycin groups and moulds the penicillins. ### Why is penicillin produced by fed-batch rather than simple batch culture? Slow, controlled carbon feeding holds the mould in the secondary-metabolite (idiophase) state where penicillin is made; abundant glucose would drive growth and repress product formation. ### What is downstream processing in fermentation? The recovery train after fermentation — broth filtration to remove biomass, solvent extraction or ion exchange, carbon decolourisation, concentration, crystallisation and drying — taking the metabolite to pharmacopoeial purity. ### How does fermentation contribute to steroid medicines? Microorganisms perform selective transformations such as the Rhizopus 11-alpha hydroxylation of progesterone, installing oxygen where chemical synthesis cannot — the key step that industrialised corticosteroid production. ### Name non-antibiotic pharmaceutical products of fermentation. Vitamin B12, amino acids such as lysine, citric acid, enzymes including penicillin acylase, dextran for plasma expanders, ethanol, and steroid intermediates for semi-synthesis.