Team:Paris/Perspectives

Metabolic engineering of polyhydroxyalkanoate biosynthesis pathways

Human overpopulation combined with the current lifestyle urges the rational, efficient, and sustainable use of natural resources to produce environmentally friendly plastic materials such as polyhydroxyalkanoic acids (PHAs), whose production/degradation cycle reduces undesirable wastes and emissions. we hope that if we applied our system to pathways that have differentes cross linked intermediaries like the biosynthesis of PHA (figure 1), by the FIFO we will optimized the expression of the differentes genes in order to avoid waste producte that will increase impurities. Our strategy consists on replacing the RFP,CFP and YFP genes by the PhaA ,PhaB and PhaC genes in our final system (containing oscillation,FIFO,synchronisation modules).

This strategy is more efficient than a constitutive activation for 3 main reasons:

• First, in this application the NADPH, which is a cellular metastable fuel, is used by the PhaB to synthesize bioplastic. This molecule is very important for many metabolic pathways in bacteria. A NADPH recuperation step is then needed to ensure other metabolic activities to go on. We can then make the hypothesis that if the PhaB is always activated the bacteria will get exhausted and die quickly. In our system, the bacteria will have a NADPH recuperation step, this is why we hope bacteria will live more than in an usual chemoreactor.

• Secondly, we hope that our system will increase the purity and the rate of PHA obtain because we don't activate the 3 genes simultaneously, instead of that we activate by a FIFO order system the 3 genes so we will avoid lost of acetoacetylcoA or others important intermediary product in others metabolic pathways.

In conclusion,our bacterioclock can be use to obtain many polymers or proteins fibers that their production pass by a lot of methabolic cross linked intermediary, in those situations the FIFO order may optimized the purity and the rate of the final products.

Bibliography