Systems Biocatalysis: Development and engineering of cell-free “artificial metabolisms” for preparative multi-enzymatic synthesis

• Published in: New biotechnology 2015-12, Vol.32 (6), p.658-664
• Main Author: Fessner, Wolf-Dieter
• Format: Article
• Language: English
• Subjects: Animals; Biocatalysis; Cell-Free System - physiology; Computer Simulation; Humans; Metabolic Engineering - methods; Metabolic Flux Analysis - methods; Models, Biological; Multienzyme Complexes - metabolism; Synthetic Biology - methods
• ISSN: 1871-6784; 1876-4347
• DOI: 10.1016/j.nbt.2014.11.007

Whole-cell biocatalysis in vivo compared to artificial metabolic pathways assembled in vitro. •Efficient bioproduction of non-natural targets incompatible with living systems.•Novel pathways using enzymes engineered for substrate promiscuity.•Examples: phosphosugar, glycolysis intermediates, oxidative pathways, sialoconjugates.•Artificial cell-free systems are easy to assemble, operate, and optimize.•Technology offers high freedom to operate. Systems Biocatalysis is an emerging concept of organizing enzymes in vitro to construct complex reaction cascades for an efficient, sustainable synthesis of valuable chemical products. The strategy merges the synthetic focus of chemistry with the modular design of biological systems, which is similar to metabolic engineering of cellular production systems but can be realized at a far lower level of complexity from a true reductionist approach. Such operations are free from material erosion by competing metabolic pathways, from kinetic restrictions by physical barriers and regulating circuits, and from toxicity problems with reactive foreign substrates, which are notorious problems in whole-cell systems. A particular advantage of cell-free concepts arises from the inherent opportunity to construct novel biocatalytic reaction systems for the efficient synthesis of non-natural products (“artificial metabolisms”) by using enzymes specifically chosen or engineered for non-natural substrate promiscuity. Examples illustrating the technology from our laboratory are discussed.