Apologies for the late report, these should come out on Fridays in the future, but welcome to the first weekly report for iGEM Summer 2015! Our goal with these reports is to keep everyone in iGEM in the loop on the development of the project this summer.
So, starting things off with last week. On Tuesday, after getting our desk space and lab approval to Bindley, we dug into the biodigester project, starting with researching the enzymes we would need to do all of the breakdown in our preprocess. Things were looking good when on Wednesday, we met with Dr. Mosier (ABE professor who does research on biodigester pretreatment) to ask about how our solution would compare to current practices.
Dr. Mosier informed us that current industrial pretreatments essentially pressure cook the plant matter, exposing it to high temperature and high pressure. This melts the lignin, because lignin is hydrophobic, it wants to reduce its surface area as much as possible, so it clumps into small spheres. This allows the other enzymes (cellulases and hemicellulases) to go in and breakdown those polysaccharides (which happens in the biodigester). It turns out that lignin monomers actually inhibit one type of cellulose activity so our solution of just breaking apart the lignin may have a counter-productive effect on the efficiency of the biodigester. Dismayed with this news, we felt as though we had hit a dead end Wednesday afternoon. On Thursday, we resurrected the microbial desalination cell project as a back-up and began looking at details pertaining to that one. We found some great potential for a project.
On Friday, Arren discovered a paper in which a group of synthetic biologists had engineered a yeast cell to perform all of the biodigester processes except pretreatment. Suddenly, our lignin-breakdown idea was relevant again because we would breakdown the lignin but it would not inhibit the cellulase activity because the cellulases are only present inside the cell while the lignin is only outside of the cell. We also continued to research background on the fuel cell project and found a number of different areas we could focus on, including the production of electron conducting filaments called nanowires, focusing on increased electron shuttling between cells, and the application of this to a desalinating fuel cell (which would be new for iGEM).