OPEN ACCESS
Research Article
06 October 2021

Aromatic dimer dehydrogenases from Novosphingobium aromaticivorans reduce monoaromatic diketones

Abstract

Lignin is a potential source of valuable chemicals, but its chemical depolymerization results in a heterogeneous mixture of aromatics and other products. Microbes could valorize depolymerized lignin by converting multiple substrates into one or a small number of products. In this study, we describe the ability of Novosphingobium aromaticivorans to metabolize 1-(4-hydroxy-3-methoxyphenyl)propane-1,2-dione (G-diketone), an aromatic Hibbert diketone which is produced during formic acid-catalyzed lignin depolymerization. By assaying genome-wide transcript levels from N. aromaticivorans during growth on G-diketone and other chemically-related aromatics, we hypothesized that the Lig dehydrogenases, previously characterized as oxidizing β-O-4 linkages in aromatic dimers, were involved in G-diketone metabolism by N. aromaticivorans. Using purified N. aromaticivorans Lig dehydrogenases, we found that LigL, LigN, and LigD each reduced the Cα ketone of G-diketone in vitro but with different substrate specificities and rates. Furthermore, LigL, but not LigN or LigD, also reduced the Cα ketone of 2-hydroxy-1-(4-hydroxy-3-methoxyphenyl)propan-1-one (GP-1) in vitro, a derivative of G-diketone with the Cβ ketone reduced, when GP-1 was provided as a substrate. The newly identified activity of these Lig dehydrogenases expands the potential range of substrates utilized by N. aromaticivorans beyond what has been previously recognized. This is beneficial both for metabolizing a wide range of natural and non-native depolymerized lignin substrates and for engineering microbes and enzymes that are active with a broader range of aromatic compounds.
Importance
Lignin is a major plant polymer composed of aromatic units that have value as chemicals. However, the structure and composition of lignin has made it difficult to use this polymer as a renewable source of industrial chemicals. Bacteria like Novosphingobium aromaticivorans have the potential to make chemicals from lignin not only because of their natural ability to metabolize a variety of aromatics but also because there are established protocols to engineer N. aromaticivorans strains to funnel lignin-derived aromatics into valuable products. In this work, we report a newly discovered activity of previously characterized dehydrogenase enzymes with a chemically-modified byproduct of lignin depolymerization. We propose that the activity of N. aromaticivorans enzymes with both native lignin aromatics and those produced by chemical depolymerization will expand opportunities for producing industrial chemicals from the heterogenous components of this abundant plant polymer.
Formats available

You can view this article in different formats.

Information & Contributors

Information

Published In

Applied and Environmental Microbiology cover image
Applied and Environmental Microbiology
Preprint6 October 2021
eLocator: AEM.01742-21
PubMed: 34613756

History

Published online: 6 October 2021

Permissions

Request permissions for this article.

Contributors

Authors

DOE Great Lakes Bioenergy Research Center, Univ. of Wisconsin-Madison, Madison, WI, USA
Wisconsin Energy Institute, Univ. of Wisconsin-Madison, Madison, WI, USA
Yanjun Ma
DOE Great Lakes Bioenergy Research Center, Univ. of Wisconsin-Madison, Madison, WI, USA
Wisconsin Energy Institute, Univ. of Wisconsin-Madison, Madison, WI, USA
Jose M. Perez
DOE Great Lakes Bioenergy Research Center, Univ. of Wisconsin-Madison, Madison, WI, USA
Wisconsin Energy Institute, Univ. of Wisconsin-Madison, Madison, WI, USA
Department of Civil and Environmental Engineering, Univ. of Wisconsin-Madison, Madison, WI, USA.
DOE Great Lakes Bioenergy Research Center, Univ. of Wisconsin-Madison, Madison, WI, USA
Wisconsin Energy Institute, Univ. of Wisconsin-Madison, Madison, WI, USA
Wayne S. Kontur
DOE Great Lakes Bioenergy Research Center, Univ. of Wisconsin-Madison, Madison, WI, USA
Wisconsin Energy Institute, Univ. of Wisconsin-Madison, Madison, WI, USA
Daniel R. Noguera
DOE Great Lakes Bioenergy Research Center, Univ. of Wisconsin-Madison, Madison, WI, USA
Wisconsin Energy Institute, Univ. of Wisconsin-Madison, Madison, WI, USA
Department of Civil and Environmental Engineering, Univ. of Wisconsin-Madison, Madison, WI, USA.
DOE Great Lakes Bioenergy Research Center, Univ. of Wisconsin-Madison, Madison, WI, USA
Wisconsin Energy Institute, Univ. of Wisconsin-Madison, Madison, WI, USA
Department of Bacteriology, Univ. of Wisconsin-Madison, Madison, WI, USA

Metrics & Citations

Metrics

Citations

View Options

Media

Figures

Other

Tables

Share

Metrics & Citations

If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.

Share Options
Share the article link

Share on social media
Get Access
LOGIN OPTIONS
Non-Member Login
Buy Article
Applied and Environmental Microbiology Vol.0 • Issue ja • ASM Journals Pay Per View, PPV 25
Journal Subscription
Applied and Environmental Microbiology
ASM members can purchase subscriptions to journals.
Join or renew

Restore your content access

Enter your email address to restore your content access:

Note: This functionality works only for purchases done as a guest. If you already have an account, log in to access the content to which you are entitled.

View Options
Tables
Figures and Media
References
American Society for Microbiology ("ASM") is committed to maintaining your confidence and trust with respect to the information we collect from you on websites owned and operated by ASM ("ASM Web Sites") and other sources. This Privacy Policy sets forth the information we collect about you, how we use this information and the choices you have about how we use such information.
FIND OUT MORE about the privacy policy