Structural analysis, multiple kinetic measurements, and binding studies require the production of adequate amounts of soluble target protein. This task is frequently laborious because of low protein-expression levels and high insolubility.
In labs without bioreactors, dozens of shake-flask cultivations need to be run in parallel, and large cell-culture volumes need to be juggled during collection and purification. As a result, many labs desire an alternate cultivation method that can provide enhanced protein yield.
In addition, metabolic engineering and directed evolution of proteins are responsible for the introduction of thousands of strain variants, all of which need to be screened. This process requires high-throughput screening methods, which in turn require a large number of physiologically healthy cells.
Traditional systems for shake-flask or multiwell-plate cultures have been based on cultivation media in batch mode, which has several limitations. For example, Luria-Bertani (LB) and Terrific Broth (TB) media are supplied with the components already in the cultivation. Due to the presence of large quantities of glucose, the bacteria grow rapidly, and the corresponding high respiratory rate exceeds the oxygen-transfer capacity of the cultivation vessel, leading to anaerobic conditions.
In these conditions, the culture media lose control of pH, and dissolved oxygen and the growth-inhibitory effect of overflow metabolites becomes more abundant. These factors contribute to the inability of cultures to reach high cell density and good recombinant protein production.