(328b) Will Cell-Free Synthetic Pathway Biotransformation (SyPaB) Compete with Microbial Fermentation for Producing Biocommodities?

A single enzyme can catalyze a one-step chemical reaction, while a microorganism can transform a complicated chemical reaction by integrating numerous enzymatic steps. In vitro (cell free) synthetic biology projects are a largely unexplored strategy. Different from most of cell-free synthetic biology projects that produce high-value biopolymers (e.g., proteins) from small building bricks, cell-free synthetic pathway biotransformation (SyPaB) is to in vitro assemble a number of enzymes and coenzymes for producing low-value products (e.g., hydrogen) by breaking down natural biopolymers (e.g., cellulose and starch). Recently, novel synthetic pathways composed of 13-14 enzymes have been demonstrated to produce nearly 12 molecules of hydrogen per molecule of glucose unit of starch or cellulosic materials and water as C6H10O5 (aq) + 7 H2O (l) --> 12 H2 (g) + 6 CO2 (g) [1,2]. Here we will further analyze the technological and economical feasibility of SyPaB for producing low-value high-volume biocommodities. SyPaB is expected to have comparative advantages over microbial fermentations, such as high product yield, fast reaction rate, high product titer, simple product separation, easy control, and so on.

[1] Y.-H. P. Zhang, B. R. Evans, J. R. Mielenz, R. C. Hopkins, M. W. W. Adams, PLoS One 2007, 2, e456.

[2] X. Ye, Y. Wang, R. C. Hopkins, M. W. W. Adams, B. R. Evans, J. R. Mielenz and Y.-H. P. Zhang, ChemSusChem, 2009, 2, 149-152.