Microbial cell factory is an approach to bioengineering which considers microbial cells as a production facility in which the optimization process largely depends on metabolic engineering.[1] MCFs is a derivation of cell factories, which are engineered microbes and plant cells.[2] In 1980s and 1990s, MCFs were originally conceived to improve productivity of cellular systems and metabolite yields through strain engineering.[3] A MCF develops native and nonnative metabolites through targeted strain design.[4] In addition, MCFs can shorten the synthesis cycle while reducing the difficulty of product separation.