The energy in the system seems to be coming from ATP which is used to move energy around in both animals and plants, so it could presumably be wired to photosyn

The energy in the system seems to be coming from ATP which is used to move energy around in both animals and plants, so it could presumably be wired to photosynthesis (which I assume is what the researchers had in mind — take the process plants use to store energy by converting water + C02 into sugar and replace it with something more efficient). And that's the limit of my high school organic chemistry. And e coli can be modified to do photosynthesis too.