A stirred tank bioreactor is a vessel used for growing microorganisms or cells in a controlled environment. It typically consists of a cylindrical tank equipped with an impeller to mix the contents, ensuring uniform distribution of nutrients and oxygen. This design allows for optimal growth conditions, making it suitable for various applications in biotechnology and pharmaceuticals. These bioreactors can be operated in batch, fed-batch, or continuous modes, depending on the desired outcome. They are often equipped with sensors to monitor parameters like temperature, pH, and dissolved oxygen, which are crucial for maintaining the health of the cultured cells or microorganisms.