It is amazing, to me anyways, how much we borrow from Mother Nature. Legos are no different. These small pieces of plastic that can be connected with infinite possibilities have stirred the imagination of children and adults alike.
There is a perfect example of Nature’s Lego set within the genomes of microorganisms that degrade plant matter using large protein complexes called cellulosomes (see this post). Clostridium thermocellum is a model organism for this.
Thanks to its ability to interchange components, both the enzymes to degrade cellulose and the protein scaffold to attach these enzymes, C. thermocellum can optimize degradation any different sources of plant material. Shown in the my illustration above is only one assembly. The cellulosomes illustrated are of the actual protein structures (or models if no structure known) of the components. Essentially, there is one scaffold protein, OlpB, which can have up to 7 other scaffold proteins attached. In the case above, I have attached 7 CipA scaffoldins each with 9 cellulose degrading enzymes. So in total, each cellulosome shown has 63 enzymes to beakdown the cellulose polymers shown in brown. Those are actual cellulose polymers based upon the reported structure of cellulose in a crystal lattice.
I haven’t shown yet, however, larger cellulosomes or the other approach microorganisms use to break down plant material. Others can use excreted cellulases that release the sugar molecules for the microbe to transport into the cell. This has been demonstrated now in the bacterial “lab rat” organism E. coli. The goal is to find the right strategy to make this process cost effective and scalable for mass production of biofuels. The ultimate coal is consolidated bioprocessing in which a single organism or culture can both degrade the biomass and convert it into a particular biofuel like ethanol or diesel products. I hope to have an animation of this, but that is a more long term goal. Hope you are able to better understand strategies bacteria (and scientists and engineers) use to break down plant cell wall material.
- Breaking down the wall: Illustration of the cellulosome as an impressive bacterial machine to degrade plants…think Legos (mhrussel.wordpress.com)
- Biofuel From Wood: Researchers Look For Best Enzymes (scienceworldreport.com)
- Digestive Systems (breakinggroundagscience.wordpress.com)
- Biofuels (tmonicaortega.wordpress.com)