Bioreactor
A bioreactor is a vessel in which living cells or enzymes are grown under controlled conditions to make a product or carry out a process. Bioreactors range from small flasks in a laboratory to steel tanks holding tens of thousands of liters.
A bioreactor is a vessel in which living cells or enzymes are grown under controlled conditions to make a product or carry out a process. Bioreactors range from small flasks in a laboratory to steel tanks holding tens of thousands of liters.
Design: What Is Controlled?
A common type, the stirred-tank bioreactor, has an agitator to mix the culture and a sparger to bubble in air. Sensors monitor temperature, pH, dissolved oxygen and foam, and computers adjust heating, acid or base addition, and gas flow to hold conditions steady. Bioreactors are run as batch cultures, in which nutrients are supplied once, as fed-batch cultures, in which nutrients are added gradually, or as continuous cultures with constant inflow and outflow.
Products: What Is Made in Them?
Microbes in bioreactors make antibiotics, enzymes, vitamins and the insulin produced by recombinant DNA technology in modified bacteria and yeasts. Cultured mammalian cells make antibody drugs, and the mRNA of vaccines is made in cell-free reactors using enzymes. Microbes are also used in the treatment of wastewater and in bioremediation.
Modeling and Scale-Up: What Makes It Hard?
Conditions in a large tank differ from those in a small flask, since mixing and oxygen supply become limiting, so engineers use models of the cell's metabolism, such as flux balance analysis, to predict and tune performance. Work on strains is part of metabolic engineering and synthetic biology, and the whole field is a part of biotechnology.
Bioreactor at a Glance
| Property | Value |
|---|---|
| Common type | Stirred-tank |
| Controlled | Temperature, pH, oxygen, nutrients |
| Modes | Batch, fed-batch, continuous |