What are the advantages of cell-free protein expression system over the traditional in vivo systems?

There are several advantages of CFPS over the traditional in vivo system. One advantage includes its open system. The open system of CFPS allows for greater control and manipulation of the reaction conditions. Another advantage is the ability to focus all system energy on production of the target protein. In contrast, in vivo systems typically use cellular resources among various cellular processes, leading to limitations in protein expression levels. Another advantage is the elimination of reliance on living cells and therefore faster synthesis. This independence allows for rapid protein generation without the limitations caused by cellular growth. These systems also enable protein labeling with altered amino acids, as well as expression of proteins which undergo rapid proteolytic degradation by proteases. Additionally, it is easier to express multiple proteins simultaneously (e.g. testing protein mutations by expression on a small scale from different recombinant DNA templates).