Bacteria Breaking Down Lignins

  • Author: Meghan Campbell
  • Published: 26 March 2018
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
  • Source / Publisher: Proceedings of the National Academy of Sciences/National Academy of Sciences
thumbnail image: Bacteria Breaking Down Lignins

One of the largest components of plant cells, lignin, could be converted into useful chemical building blocks, but scientists currently lack efficient methods to unlock this potential. Lignin is composed of polyphenylpropanoid units that, when broken down, afford chemicals that can be turned into plastics, nylon, or resins. So far, lignin has escaped digestion by bacterial culture because its aromatic byproducts, i.e. vanillin, inhibit bacterial growth. In addition, it is hard for bacteria to take up these aromatic compounds and much of the substrate remains in the surrounding culture.


Seema Singh and colleagues, Sandia National Laboratories, CA, USA, have tackled these issues by engineering E. coli that can both take up vanillin and use it to produce catechol without suffering from toxic effects. The team alleviated most of the toxicity associated with this molecule by introducing a biosynthetic pathway that breaks down vanillin. In addition, they put the pathway under the control of a promoter that is induced by vanillin, which means the pathway is self-regulated. Such a promoter element also eliminates the need for the more expensive inducer, isopropyl-β-D-1-thiogalactopyranoside (IPTG), which would be too costly for the industrial-scale break down of lignin.


In a second modification, the researchers added CouP (a transporter known to import aromatic substrates into bacteria) so the E. coli could more efficiently process vanillin. Together, these modifications significantly increased the production of catechol from lignin aromatics, which represents an important prototype for the industrial-scale use of lignins. Further engineering of the promoter and the biosynthetic pathway could increase the production of catechol or allow other important building blocks to be made.


 

Article Views: 734

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

Bookmark and Share

If you would like to reuse any content, in print or online, from ChemistryViews.org, please contact us first for permission. more


CONNECT:

ChemistryViews.org on Facebook

ChemistryViews.org on Twitter ChemistryViews.org on YouTube ChemistryViews.org on LinkedIn Sign up for our free newsletter


A product of ChemPubSoc Europe (16 European Chemical Societies)and Wiley-VCH