Title: Bioprocess development for muconic acid production from aromatic compounds and lignin

Abstract

Muconic acid (MA) is a bio-based platform chemical that can be converted into the commodity petrochemical building blocks adipic acid or terephthalic acid, or used in emerging, performance-advantaged materials. MA is a metabolic intermediate in the ß-ketoadipate pathway, and can be produced from carbohydrates or other traditional carbon sources via the shikimate pathway. MA can also be produced from lignin-derived aromatic compounds with high atom efficiency through aromatic-catabolic pathways. Metabolic engineering efforts to date have developed efficient muconic acid-producing strains of the aromatic-catabolic microbe Pseudomonas putida KT2440, but the titers, productivities, and yields from aromatic compounds in most cases remain below the thresholds needed for industrially-relevant bioreactor cultivations. To that end, this work presents further process and host development towards improving MA titers, yields, and productivities, using the hydroxycinnamic acids, pcoumaric acid and ferulic acid, as model aromatic compounds. Coupling strain engineering and bioprocess development enabled the discovery of new bottlenecks in P. putida that hinder MA production from these compounds. A combination of gene overexpression and removal of a global catabolic regulator resulted in highyielding strains (100% molar yield). Maximum MA titers of 50 g/L, which is near the lethal toxicity limit in this bacterium, and productivities over 0.5more » g/L/h were achieved in separate process configurations. Additionally, a high-pH feeding strategy, which could potentially reduce the salt load and enable higher titers by decreasing product dilution, was tested with model compounds and lignin-rich streams from corn stover and a complete conversion of the primary monomeric aromatic compounds to MA was demonstrated, obtaining a titer of 4 g/L. Overall, this study presents a step forward for the production of value-added chemicals from lignin and highlights critical needs for further strain improvement and bioprocess development that can be applied in the biological valorization of lignin.« less

Authors:

Salvachúa, Davinia  ^[1];

• Search DOE PAGES for author "Salvachúa, Davinia"
• Search DOE PAGES for ORCID "0000-0003-0799-061X"

Johnson, Christopher W.  ^[1];

• Search DOE PAGES for author "Johnson, Christopher W."
• Search DOE PAGES for ORCID "0000-0002-2979-4751"

Singer, Christine A. ^[1]; Rohrer, Holly ^[1]; Peterson, Darren J. ^[1]; Black, Brenna A. ^[1]; Knapp, Anna ^[1]; Beckham, Gregg T.  ^[1]

• Search DOE PAGES for author "Beckham, Gregg T."
• Search DOE PAGES for ORCID "0000-0002-3480-212X"

---

+ Show Author Affiliations

1. National Renewable Energy Lab. (NREL), Golden, CO (United States)

Publication Date:

Thu Oct 11 00:00:00 EDT 2018

Research Org.:

National Renewable Energy Lab. (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Sustainable Transportation Office. Bioenergy Technologies Office

OSTI Identifier:

1480230

Alternate Identifier(s):

OSTI ID: 1477891

Report Number(s):

NREL/JA-2A00-72687
Journal ID: ISSN 1463-9262; GRCHFJ

Grant/Contract Number:  

AC36-08GO28308

Resource Type:

Accepted Manuscript

Journal Name:

Green Chemistry

Additional Journal Information:

Journal Volume: 20; Journal Issue: 21; Journal ID: ISSN 1463-9262

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

09 BIOMASS FUELS; muconic acid; bioprocessing; aromatic compounds; lignin