Biological modelling is a major component in synthetic biology that uses experimental data to visually communicate efficiency and yields of the system in question. This is especially important in modified systems, such as our photosynthetic, hydrogen producing E. coli.
The first steps to engineering an eco-friendly, sustainable hydrogen fuel cell was to genetically modify the chlorophyll a pathway, which could be used by photosystem II (PSII) to absorb energy from sunlight and transfer it to a hydrogenase for hydrogen production in E. coli. Fig 1. Project overview: PPIX precursor showing the changes undergone to form final product of the first pathway; chlorophyll a. Chlorophyll a absorbs photons from sunlight, providing energy to photosystem II to split water molecules to release O2, hydrogen ions and electrons. The latter two products are then diverged from photosystem I to a hydrogenase that then uses this energy to create hydrogen gas.
The model we created was based off enzyme kinetic data found in literature, and from previous Macquarie iGEM wiki’s. The enzyme kinetic model developed by the 2015 Macquarie iGEM team took the 5-aminolevulinic acid (ALA) precursor and modelled the pathway of its intermediates up to the production of protoporphyrinogen IX (PPIX). This year, the 2016 Macquarie iGem team have furthered this model and taken it through to the production of chlorophyll a (see figure 1). Matlab was the program chosen to create our model. Further models could enable us to optimise the hydrogen production yield.