Biotechnology - Yu.O. Sazykin 2006

General Biotechnology
Main Stages of the Biotechnological Process
Preparation of Inoculum

It must be emphasized that every production culture used as a producer of the target product must have a specification passport indicating its name, genus (species), collection number, average activity level, batch, release date, expiration date, and CHARACTERISTICS OF THE medium used for its cultivation and storage.

The process of preparing the inoculum is multi-stage, consisting of several consecutive steps. First, the initial culture is grown on an Agar medium in a test tube. At this stage, plating the initial culture onto the agar medium allows for morphological examination to verify the purity of the culture. Next, cultivation is carried out in flasks with a liquid medium on a shaker. At this stage, aeration is introduced, and the initial culture is mixed with the liquid nutrient medium at a specific Temperature. Afterward, the initial culture mixed with the liquid nutrient medium is transferred into a seed tank (inoculator) at 10-25% of the inoculator's working volume. Mixing and aeration are also performed here. Sometimes the seed tank is referred to as a small fermenter and the production vessel as a large one, though there are no Functional differences between them.

Preparing the inoculum involves a stepwise increase in biomass. Therefore, one or more seed tanks of increasing volume may be used (the cultivation of the inoculum is typically scaled up to about 5–10% of the volume of the main fermenter). The inoculator is equipped with an air supply and filtration system. Like the main fermenter, this vessel is fitted with inspection ports, sensors, baffles, etc.

In the seed tank, the nutrient medium remains stable. In the fermenter, however, as the target product accumulates, the concentrations of carbon and nitrogen decrease—meaning the COMPOSITION OF THE nutrient medium changes over time. As a result, the microorganisms begin to experience nutrient starvation, and their physiological response to this stress is the production and release of substances such as Antibiotics.