Transcript Efficient Environment, Part II: Phenol Resins

Efficient Environment, Part II:
Phenol Resins
Structure of Phenol Resins
Many phenolic resins are composed of formaldehyde and phenols
Sub-project 1: Phenol metabolism
• Goal: Engineer E. coli to metabolize phenol as a carbon
source, linking it to cellular respiration
Meta- and Ortho- Phenol Metabolism
Tuah 2006.
A schematic representation of the central carbon metabolism of E. coli (adapted from ref. 35)
Phenol as a Carbon Source
By-products of phenol
metabolism would enter
glycolysis pathway or TCA
Cycle of E. coli
Shlomi T. et.al. PNAS 2005;102:7695-7700
©2005 by National Academy of Sciences
The sequences of the enzymes for
both ortho- and meta- pathways are
available online
Sub-Project 2: Formaldehyde Metabolism
• Goal: Engineer E. coli to metabolize formaldehyde as
respiration precursor, bypassing the detoxification pathway
Oxidation versus assimilation
3-Hexulose-6-Phosphate Synthase: Condensation of ribulose 5phosphate with formaldehyde to form 3-hexulose 6-phosphate.
phospho-3-hexuloisomerase: 3-hexulose 6-phosphate to form
D-fructose-6-phosphate
http://sti.srs.gov/fulltext/ms2001058/fig1.gif
Project in Context
•
Tsai et al. isolated a strain of yeast capable of degrading both phenol (metafission) and formaldehyde, but acknowledged that “a microbe with a
biodegrading power toward phenol and formaldehyde concurrently has been
scarcely reported” (Tsai et al. 2005)
•
Gusse et al. isolated white-rot fungus capable of degrading phenolic resins but
efficiency uncertain (Gusse et al. 2006)
•
Hidalgo et al. showed the ability of Rhodococcus erythropolis UPV-1 to grow
on phenol and remove formaldehyde
•
Linking both to cellular respiration (not just detoxification) in E. coli would
facilitate future projects to make PR degradation more efficient--more
genetically tractable and better understood
Questions to Consider
• Can we make phenol the sole or preferred carbon source?
• Competition with formaldehyde resistance pathway?
• Linking to other pathways/phenomena in bacteria? (e.g.
quorum sensing, biofilms, etc.)