title: Engineering E. coli-E. coli cocultures for production of muconic acid from glycerol.
abstract: BACKGROUND
  cis, cis-Muconic acid is an important chemical that can be biosynthesized from simple substrates in engineered microorganisms. Recently, it has been shown that engineering microbial cocultures is an emerging and promising approach for biochemical production. In this study, we aim to explore the potential of the E. coli-E. coli coculture system to use a single renewable carbon source, glycerol, for the production of value-added product cis, cis-muconic acid.
  
  
  RESULTS
  Two coculture engineering strategies were investigated. In the first strategy, an E. coli strain containing the complete biosynthesis pathway was co-cultivated with another E. coli strain containing only a heterologous intermediate-to-product biosynthetic pathway. In the second strategy, the upstream and downstream pathways were accommodated in two separate E. coli strains, each of which was dedicated to one portion of the biosynthesis process. Compared with the monoculture approach, both coculture engineering strategies improved the production significantly. Using a batch bioreactor, the engineered coculture achieved a 2 g/L muconic acid production with a yield of 0.1 g/g.
  
  
  CONCLUSIONS
  Our results demonstrate that coculture engineering is a viable option for producing muconic acid from glycerol. Moreover, microbial coculture systems are shown to have the potential for converting single carbon source to value-added products.
authors.affiliation: Chemical Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02139, USA. zhanghr@mit.edu.
authors.forename: Haoran
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Chemical Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02139, USA. lizj@mit.edu.|Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China. lizj@mit.edu.
authors.forename: Zhengjun
authors.initials: Z
authors.lastname: Li
authors.affiliation: Chemical Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02139, USA. bpereira@mit.edu.
authors.forename: Brian
authors.initials: B
authors.lastname: Pereira
authors.affiliation: Chemical Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02139, USA. gregstep@mit.edu.
authors.forename: Gregory
authors.initials: G
authors.lastname: Stephanopoulos
mesh_terms: D019149:Bioreactors; D018920:Coculture Techniques; D004926:Escherichia coli / Q000378:metabolism*; D005990:Glycerol / Q000737:chemistry / Q000378:metabolism*; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways; D013011:Sorbic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism
chemical_list: C005939:muconic acid; D005990:Glycerol; D013011:Sorbic Acid