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Title: Base-Catalyzed Depolymerization of Solid Lignin-Rich Streams Enables Microbial Conversion

Lignin valorization offers significant potential to enhance the economic viability of lignocellulosic biorefineries. However, because of its heterogeneous and recalcitrant nature, conversion of lignin to value-added coproducts remains a considerable technical challenge. Here, we employ base-catalyzed depolymerization (BCD) using a process-relevant solid lignin stream produced via deacetylation, mechanical refining, and enzymatic hydrolysis to enable biological lignin conversion. BCD was conducted with the solid lignin substrate over a range of temperatures at two NaOH concentrations, and the results demonstrate that the lignin can be partially extracted and saponified at temperatures as low as 60 degrees C. At 120 °C and 2% NaOH, the high extent of lignin solubility was accompanied by a considerable decrease in the lignin average molecular weight and the release of lignin-derived monomers including hydroxycinnamic acids. BCD liquors were tested for microbial growth using seven aromatic-catabolizing bacteria and two yeasts. Three organisms (Pseudomonas putida KT2440, Rhodotorula mucilaginosa, and Corynebacterium glutamicum) tolerate high BCD liquor concentrations (up to 90% v/v) and rapidly consume the main lignin-derived monomers, resulting in lignin conversion of up to 15%. Furthermore, as a proof of concept, muconic acid production from a representative lignin BCD liquor was demonstrated with an engineered P. putida KT2440 strain.more » Our results highlight the potential for a mild lignin depolymerization process to enhance the microbial conversion of solid lignin-rich biorefinery streams.« less
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [3] ;  [4] ;  [5] ; ORCiD logo [2] ;  [6]
  1. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Biomass Science and Conversion Technology Dept.
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States). National Bioenergy Center
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; USDOE Joint BioEnergy Inst., Emeryville, CA (United States)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; USDOE Joint BioEnergy Inst., Emeryville, CA (United States); Univ. of California, Berkeley, CA (United States). Dept. of Chemical and Biomolecular Engineering and Bioengineering; Novo Nordisk Foundation Center for Sustainability, Lyngby (Denmark)
  5. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Biomass Science and Conversion Technology Dept.; USDOE Joint BioEnergy Inst., Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division
  6. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Biomass Science and Conversion Technology Dept.; USDOE Joint BioEnergy Inst., Emeryville, CA (United States)
Publication Date:
Report Number(s):
NREL/JA-5100-70189
Journal ID: ISSN 2168-0485
Grant/Contract Number:
AC36-08GO28308; AC02-05CH11231; NA0003525
Type:
Accepted Manuscript
Journal Name:
ACS Sustainable Chemistry & Engineering
Additional Journal Information:
Journal Volume: 5; Journal Issue: 9; Journal ID: ISSN 2168-0485
Publisher:
American Chemical Society (ACS)
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies Office (EE-3B); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; base-catalyzed depolymerization; biological conversion; lignin liquor; lignin monomers; muconic acid
OSTI Identifier:
1394906
Alternate Identifier(s):
OSTI ID: 1476536

Rodriguez, Alberto, Salvachúa, Davinia, Katahira, Rui, Black, Brenna A., Cleveland, Nicholas S., Reed, Michelle, Smith, Holly, Baidoo, Edward E. K., Keasling, Jay D., Simmons, Blake A., Beckham, Gregg T., and Gladden, John M.. Base-Catalyzed Depolymerization of Solid Lignin-Rich Streams Enables Microbial Conversion. United States: N. p., Web. doi:10.1021/acssuschemeng.7b01818.
Rodriguez, Alberto, Salvachúa, Davinia, Katahira, Rui, Black, Brenna A., Cleveland, Nicholas S., Reed, Michelle, Smith, Holly, Baidoo, Edward E. K., Keasling, Jay D., Simmons, Blake A., Beckham, Gregg T., & Gladden, John M.. Base-Catalyzed Depolymerization of Solid Lignin-Rich Streams Enables Microbial Conversion. United States. doi:10.1021/acssuschemeng.7b01818.
Rodriguez, Alberto, Salvachúa, Davinia, Katahira, Rui, Black, Brenna A., Cleveland, Nicholas S., Reed, Michelle, Smith, Holly, Baidoo, Edward E. K., Keasling, Jay D., Simmons, Blake A., Beckham, Gregg T., and Gladden, John M.. 2017. "Base-Catalyzed Depolymerization of Solid Lignin-Rich Streams Enables Microbial Conversion". United States. doi:10.1021/acssuschemeng.7b01818. https://www.osti.gov/servlets/purl/1394906.
@article{osti_1394906,
title = {Base-Catalyzed Depolymerization of Solid Lignin-Rich Streams Enables Microbial Conversion},
author = {Rodriguez, Alberto and Salvachúa, Davinia and Katahira, Rui and Black, Brenna A. and Cleveland, Nicholas S. and Reed, Michelle and Smith, Holly and Baidoo, Edward E. K. and Keasling, Jay D. and Simmons, Blake A. and Beckham, Gregg T. and Gladden, John M.},
abstractNote = {Lignin valorization offers significant potential to enhance the economic viability of lignocellulosic biorefineries. However, because of its heterogeneous and recalcitrant nature, conversion of lignin to value-added coproducts remains a considerable technical challenge. Here, we employ base-catalyzed depolymerization (BCD) using a process-relevant solid lignin stream produced via deacetylation, mechanical refining, and enzymatic hydrolysis to enable biological lignin conversion. BCD was conducted with the solid lignin substrate over a range of temperatures at two NaOH concentrations, and the results demonstrate that the lignin can be partially extracted and saponified at temperatures as low as 60 degrees C. At 120 °C and 2% NaOH, the high extent of lignin solubility was accompanied by a considerable decrease in the lignin average molecular weight and the release of lignin-derived monomers including hydroxycinnamic acids. BCD liquors were tested for microbial growth using seven aromatic-catabolizing bacteria and two yeasts. Three organisms (Pseudomonas putida KT2440, Rhodotorula mucilaginosa, and Corynebacterium glutamicum) tolerate high BCD liquor concentrations (up to 90% v/v) and rapidly consume the main lignin-derived monomers, resulting in lignin conversion of up to 15%. Furthermore, as a proof of concept, muconic acid production from a representative lignin BCD liquor was demonstrated with an engineered P. putida KT2440 strain. Our results highlight the potential for a mild lignin depolymerization process to enhance the microbial conversion of solid lignin-rich biorefinery streams.},
doi = {10.1021/acssuschemeng.7b01818},
journal = {ACS Sustainable Chemistry & Engineering},
number = 9,
volume = 5,
place = {United States},
year = {2017},
month = {8}
}