Optogenetic Amplification Circuits for Light-Induced Metabolic Control. Author Evan Zhao, Makoto Lalwani, Jhong-Min Chen, Paulina Orillac, Jared Toettcher, José Avalos Publication Year 2021 Type Journal Article Abstract Dynamic control of microbial metabolism is an effective strategy to improve chemical production in fermentations. While dynamic control is most often implemented using chemical inducers, optogenetics offers an attractive alternative due to the high tunability and reversibility afforded by light. However, a major concern of applying optogenetics in metabolic engineering is the risk of insufficient light penetration at high cell densities, especially in large bioreactors. Here, we present a new series of optogenetic circuits we call OptoAMP, which amplify the transcriptional response to blue light by as much as 23-fold compared to the basal circuit (OptoEXP). These circuits show as much as a 41-fold induction between dark and light conditions, efficient activation at light duty cycles as low as ∼1%, and strong homogeneous light-induction in bioreactors of at least 5 L, with limited illumination at cell densities above 40 OD. We demonstrate the ability of OptoAMP circuits to control engineered metabolic pathways in novel three-phase fermentations using different light schedules to control enzyme expression and improve production of lactic acid, isobutanol, and naringenin. These circuits expand the applicability of optogenetics to metabolic engineering. Keywords Transcription, Genetic, Signal Transduction, Transcription Factors, Gene Expression Regulation, DNA-Binding Proteins, Enzyme Activation, Gene Expression, Lactic Acid, Light, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Fermentation, Optogenetics, Butanols, Metabolic Networks and Pathways, Metabolic Engineering, Bioreactors, Microorganisms, Genetically-Modified, Flavanones Journal ACS Synth Biol Volume 10 Issue 5 Pages 1143-1154 Date Published 2021 May 21 ISSN Number 2161-5063 DOI 10.1021/acssynbio.0c00642 Alternate Journal ACS Synth Biol PMCID PMC8721662 PMID 33835777 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML