An in vitro synthetic biology platform for emerging industrial biomanufacturing: Bottom-up pathway design

Although most in vitro (cell-free) synthetic biology projects are usually used for the purposes of fundamental research or the formation of high-value products, in vitro synthetic biology platform, which can implement complicated biochemical reactions by the in vitro assembly of numerous enzymes and coenzymes, has been proposed for low-cost biomanufacturing of bioenergy, food, biochemicals, and nutraceuticals. In addition to the most important advantage-high product yield, in vitro synthetic biology platform features several other biomanufacturing advantages, such as fast reaction rate, easy product separation, open process control, broad reaction condition, tolerance to toxic substrates or products, and so on. In this article, we present the basic bottom-up design principles of in vitro synthetic pathway from basic building blocks-BioBricks (thermoenzymes and/or immobilized enzymes) to building modules (e.g., enzyme complexes or multiple enzymes as a module) with specific functions. With development in thermostable building blocks-BioBricks and modules, the in vitro synthetic biology platform would open a new biomanufacturing age for the cost-competitive production of biocommodities.