title: Extending shikimate pathway for the production of muconic acid and its precursor salicylic acid in Escherichia coli.
abstract: cis,cis-Muconic acid (MA) and salicylic acid (SA) are naturally-occurring organic acids having great commercial value. MA is a potential platform chemical for the manufacture of several widely-used consumer plastics; while SA is mainly used for producing pharmaceuticals (for example, aspirin and lamivudine) and skincare and haircare products. At present, MA and SA are commercially produced by organic chemical synthesis using petro-derived aromatic chemicals, such as benzene, as starting materials, which is not environmentally friendly. Here, we report a novel approach for efficient microbial production of MA via extending shikimate pathway by introducing the hybrid of an SA biosynthetic pathway with its partial degradation pathway. First, we engineered a well-developed phenylalanine producing Escherichia coli strain into an SA overproducer by introducing isochorismate synthase and isochorismate pyruvate lyase. The engineered strain is able to produce 1.2g/L of SA from simple carbon sources, which is the highest titer reported so far. Further, the partial SA degradation pathway involving salicylate 1-monoxygenase and catechol 1,2-dioxygenase is established to achieve the conversion of SA to MA. Finally, a de novo MA biosynthetic pathway is assembled by integrating the established SA biosynthesis and degradation modules. Modular optimization enables the production of up to 1.5g/L MA within 48h in shake flasks. This study not only establishes an efficient microbial platform for the production of SA and MA, but also demonstrates a generalizable pathway design strategy for the de novo biosynthesis of valuable degradation metabolites.
authors.affiliation: College of Engineering, University of Georgia, Athens, GA 30602, USA.
authors.forename: Yuheng
authors.initials: Y
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
authors.forename: Xinxiao
authors.initials: X
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
authors.forename: Qipeng
authors.initials: Q
authors.lastname: Yuan
authors.affiliation: BioChemical Engineering Program, College of Engineering, University of Georgia, Athens, GA 30602, USA. Electronic address: yajunyan@uga.edu.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Yan
mesh_terms: D019757:Carbon-Oxygen Lyases / Q000096:biosynthesis / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000096:biosynthesis / Q000235:genetics; D019751:Intramolecular Transferases / Q000096:biosynthesis / Q000235:genetics; D060847:Metabolic Engineering / Q000379:methods; D020156:Salicylic Acid / Q000378:metabolism*; D012765:Shikimic Acid / Q000378:metabolism*; D013011:Sorbic Acid / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D012765:Shikimic Acid; C005939:muconic acid; D019757:Carbon-Oxygen Lyases; D019751:Intramolecular Transferases; C058486:isochorismate synthase; D020156:Salicylic Acid; D013011:Sorbic Acid
keywords: Escherichia coli; Metabolic engineering; Microbial production; Muconic acid; Salicylic acid