title: A Two-Layer Gene Circuit for Decoupling Cell Growth from Metabolite Production.
abstract: We present a synthetic gene circuit for decoupling cell growth from metabolite production through autonomous regulation of enzymatic pathways by integrated modules that sense nutrient and substrate. The two-layer circuit allows Escherichia coli to selectively utilize target substrates in a mixed pool; channel metabolic resources to growth by delaying enzymatic conversion until nutrient depletion; and activate, terminate, and re-activate conversion upon substrate availability. We developed two versions of controller, both of which have glucose nutrient sensors but differ in their substrate-sensing modules. One controller is specific for hydroxycinnamic acid and the other for oleic acid. Our hydroxycinnamic acid controller lowered metabolic stress 2-fold and increased the growth rate 2-fold and productivity 5-fold, whereas our oleic acid controller lowered metabolic stress 2-fold and increased the growth rate 1.3-fold and productivity 2.4-fold. These results demonstrate the potential for engineering strategies that decouple growth and production to make bio-based production more economical and sustainable.
authors: Department of Biochemistry, Yong Loo Lin School of Medicine and NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore.
authors: Tat-Ming
authors: TM
authors: Lo
authors: Department of Biochemistry, Yong Loo Lin School of Medicine and NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore.
authors: Si Hui
authors: SH
authors: Chng
authors: Department of Biochemistry, Yong Loo Lin School of Medicine and NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore.
authors: Wei Suong
authors: WS
authors: Teo
authors: Department of Biochemistry, Yong Loo Lin School of Medicine and NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore.
authors: Han-Saem
authors: HS
authors: Cho
authors: Department of Biochemistry, Yong Loo Lin School of Medicine and NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore. Electronic address: bchcmw@nus.edu.sg.
authors: Matthew Wook
authors: MW
authors: Chang
mesh_terms: D004926:Escherichia coli; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D053263:Gene Regulatory Networks; D005947:Glucose; D006128:Growth; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways
chemical_list: D029968:Escherichia coli Proteins; D005947:Glucose
keywords: autonomous regulation; genetic controllers; genetic sensors; synthetic biology