Images. The page has finally been updated to include my most valued pieces. Hope you all enjoy!

Moving towards the renewables: biotech and more

Moving towards the renewables: biotech and more.

Bacteria; They’re not only for biofuel anymore. Unsung heroes for bioplastics

illustrated bacteria, microbiology, bioplastic, bioenergy, environment
Illustration of PHB within bacterial cells

I spend a lot of time on this blog illustrating and promoting the benefits of the things we can’t see, however, we can’t live without and finding new ways they can help us out. To focus on bacteria along for now, they are beneficial overwhelmingly more than they are hazardous. Lots of research is going into utilizing them in new arenas from ethanol to diesel and jet fuels.

Helping solve the forthcoming energy/climate crisis is not the only area these guys can help. Lots of bacteria, under certain environmental conditions, can and will produce huge internal polymers as carbon stores, especially when nitrogen supplies are limited. Think of this polymer like starch in plants and glycogen in mammals. Research is still ongoing into the mechanisms that regulate polymer synthesis and degradation.

The bacterial polymer is special, unlike the molecular make-up of starch or glycogen, this polymer is a class of polyhydroxyalkanoate (PHA).

Structure of poly-(R)-3-hydroxybutyrate (P3HB)
Structure of poly-(R)-3-hydroxybutyrate (P3HB) (Photo credit: Wikipedia)

One of the most prevalent forms of PHA is polyhydroxybutyrate, or PHB. Speaking from experience, PHB is an interesting macromolecule to study and observe under the microscope with cells treated with a fluorescent dye that stains PHB. PHB can account for up to 75%  of the total cell weight. PHB, and PHAs in general, can be used to make plastic thus replacing the need for petroleum based plastics.

Illustration: Synthetic Biology; Turning bacteria poop into a hot commodity

bacteria art, E. coli art, bioenergy, biomass, biodiesel
Illustration showing the concept of E. coli engineered to digest plant cell wall material (green) and produce fatty acids (white) that can be used as diesel as a waste product. The fatty acids shown are actual 3D structures of linoleic acid.

Mother Nature’s Lego Collection: Unfinished illustration of cellulose degrading polycellulosomes

biofuel, bioenergy, bacteria, microbiology, clostridium, bacteria art
Illustration of Clostridium thermocellum with two polycellulosomes (green) degrading cellulose fibers (brown). Size 2400 x 1920 px

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.

Micrograph image of C. thermocellum showing cellulosomes attached to its cell surface. Image source here.

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.