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Team:Michigan
From 2010.igem.org
Project Background
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Our team worked on two projects simultaneously this year: The Hy-Bi project and the Oil Sands Initiative: Hy-Bi The Hy-Bi project is in association with the Chemical Engineering department’s joint project to produce hydrocarbons from algae biomass, dubbed "Hy-Bi"[1,2]. This consists of hydrothermal processing of the algae followed by catalytic upgrading of the “bio crude” oil. Before the hydrothermal processing can take place the algae needs to be concentrated from 1 to 10 g/L to over 250 g/L. Traditional methods that are used like centrifugation, filtration and chemical flocculation are costly. For this project, we will be over-expressing type I pili and their associated adhesion protein, making a hyper-piliated, hyper-adhesive strain of E. coli. We hope that the extreme stickiness of the E. coli will turn them into an excellent bioflocculant- termed EcoGlue. In addition, we will also be expressing a virus protein which specifically binds to the algal species Chlorella vulgaris, a species of interest for harvesting algae oil. This protein will provide additional flocculation ability and specificity for this species. We hope that such a bioflocculant can provide a cheaper, safer alternative to chemical flocculants. Oil Sands Our team will also be working on the Oil Sands Initiative simultaneously. Tailings ponds have become a major ecological concern regarding oil sands operations due to the toxicity of the water. Oil sands companies are on zero discharge leases, so the tailings water must be held on site, which is done in retention ponds. The main cause of toxicity in tailings water has been identified as naphthenic acids (NAs), some of which can be very recalcitrant to degradation and persist in waters for decades. Thus, our will attempt to expedite the reclamation process. Two bacteria, Pseudomonas fluorescens and Pseudomonas putida, were isolated from tailings pond sediments and found to be capable of synergistically degrading >95% of a commercial mixture of NAs resembling those found in the tailings water over a 4 week period [3]. In addition, two other bacteria have shown degradation efficiencies near 100% when in an immobilized cell reactor (ICR)[4], which functionally represents a biofilm. Following these findings, the strategy we wish to implement will be to utilize the two naturally adapted Pseudomonas species and genetically engineer them to optimize their biofilm formation abilities in tailings pond water-like conditions. This would allow for easier and improved use in an ICR. Alternatively, a more organic and aesthetically pleasing method would be to create a large 'slide' or 'washboard', where the naturally adapted Pseudomonas species would grow under a constant stream of tailings water, and function similar to an ICR.
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