Team:Wisconsin-Madison

'''A tool to evaluate the translation of heterologous genes in Eschericia coli.'''

In synthetic biology, a powerful method for the production of novel metabolites is the expression of heterologous genes in Escherichia coli. A common challenge when using non-native genes in metabolic engineering is determining if they are being properly expressed. To address this issue, we have constructed a BioFusion compatible system for testing the translation of a gene of interest. This system couples the translation of the target gene to a fluorescent reporter gene. Fluorescence will only be detected when the target gene is entirely translated. This construct enables synthetic biologists to quickly determine if a gene is being expressed without the need for costly antibodies or analytical instruments (e.g. mass spectrometry). Currently, we are utilizing this cassette to troubleshoot the expression of limonene synthase, an enzyme that catalyzes the production of limonene, a monoterpene with potential as a renewable jet fuel.

SURFACE DISPLAY AND FLOCCULATION
Engineering an easy cut and paste method to display proteins
Many previous iGEM teams have had success displaying a number of different enzymes and proteins on the surface of a cell. However, many of the methods used were specific to a lab at their respective universities. We wanted to create a common “display vector” that all teams can use to display any part they would like. This vector also allows for the use of standard digestion and ligation protocols, and not newer cloning methods like Gibson or PIPE. We also wanted to characterize a surface displayed Beta-Glucosidase part which would allow the degradation of cellobiose, which has large implications for the alternative fuel industry.
Flocculation
Flocculation is the process of individual cells, suspended in solution, coming together to form larger clumps, subsequently settling out of solution. The practical applications of having strains of bacteria capable of doing this in response to an inducible signal are numerous. This project seeks to us the high affinity binding interaction between the LamB maltoporin, and gpJ—a truncated portion of the C-terminal of the J protein of the lambda bacteriophage. gpJ is the region of the J protein that is responsible for the binding of the lambda phage to e. coli, at its surface receptor—LamB. By surfacing displaying a fusion of gpJ and maltose binding protein (MBP) with ice nucleation protein (INP), and over-expressing LamB in response to IPTG induction, we hope to produce a form of inducible flocculation in E. Coli Cells. Furthermore, by using the sigma-S promoter, we hope to make this flocculation occur automatically at the beginning of the stationary phase of the cell cycle. This would make the system ideal for a bioreactor which produces a growth phase metabolite, such as limonene.