Cell-free platforms for flexible expression and screening of enzymes

As was witnessed from PCR technology, in vitro applications of biosynthetic machinery can expand the horizon of biotechnology. Cell-free protein synthesis has emerged as a powerful technology that can potentially transform the concept of bioprocess. With the ability to harness the synthetic power of biology without many of the constraints of cell-based systems, cell-free protein synthesis enables instant creation of protein molecules from diverse sources of genetic information. Enzyme discovery and engineering is the field of particular interest among the possible applications of cell-free protein synthesis since many of the intrinsic limitations associated with traditional cell-based expression screening of enzymes can be effectively addressed. Cell-free synthesis not only offers excellent throughput in the generation of enzymes, it allows facile integration of expression and analysis of enzymes, greatly accelerating the process of enzyme discovery. This review article is thus intended to survey recent progress in cell-free protein synthesis technology focused on its applications in enzyme expression and screening.