A biochemical process such as fermentation that involves the culture of a single type or strain of microorganism. A process bioreactor or fermenter is first fully sterilized before being inoculated with a small volume of the required living and viable microorganism. The process is then operated in a monoseptic state by controlling the ports into and out of the bioreactor by filtration and the use of septic seals to avoid microbial contamination by other microorganisms.