Fermenting Vat

a hermetically sealed, cylindrical vessel for the culturing of microorganisms in a nutrient medium under sterile conditions, intensive mixing, continuous aeration with sterile air, and constant temperature. It consists of a casing equipped with a diffuser for the introduction of sterile air and an electric mixer. Thin metal strips are attached crosswise along the inner surface of the casing, serving as baffles for increasing mixing efficiency. Vat capacities range up to 30 liters for laboratory use, from 0.05 to 5 m³ for pilot plant experiments, and from 50 to 100 m³ for industrial use.

Laboratory fermenting vats may be made of heat-resistant glass so that they can be sterilized in autoclaves; large vats are made of stainless steel and are equipped with a steam jacket for sterilization and temperature maintenance. Fermenting vats are usually equipped with devices for the measurement and control of the temperature, the amount of air introduced, and the interior pressure. When necessary, they are additionally equipped with devices for the measurement and control of the pH of the medium, the concentration of dissolved oxygen in the culture liquid, and the amount of carbon dioxide in the exhaust air, as well as a signal indicator for the foam level and devices for mechanical or chemical foam reduction. Vats designed for the continuous culturing of microorganisms are additionally equipped with reservoirs for storing components of the nutrient medium and pumps for continuous feeding of the components into the fermenter; both reservoirs and pumps can be sterilized.

Fermenting vats are used in industry in the microbiological synthesis of antibiotics, enzymes, vitamins, amino acids, nucleotides, and protein-vitamin concentrates. They also find application in research in microbiology, biochemistry, and related disciplines.