The authors call them "cyborg bacteria", but as far as I can see they didn't change the bacteria artificially, they just put them in unusual conditions, including poison. They used bacteria that get rid of poisonous substances (such as cadmium) by forming crystals out of them. Under the right conditions, they could grow cadmium sulfide on their surface - a semiconductor that collects light and makes the energy available for chemical reactions. The bacteria produce acetic acid, an important substance for the chemical industry, out of CO2, water and light. The efficiency of this conversion is quoted as 80%, to be compared to ~10% for photosynthesis in plants under ideal conditions. The produced substances are different, however, so direct comparisons are not necessarily perfect. American Chemical Society news BBC news The usual caveats apply, of course: It works in the lab, it is unclear if the process can be scaled up and how much an industrial application would cost. Replacing cadmium by a less toxic substance would be nice as well. At least less toxic to humans, as "being toxic to bacteria" is part of the concept.