Just add poison: Bacteria outperform plants in efficiency

[mfb]

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.

 

[jim mcnamara]

I'm not sure what you are on about here. The statement that single celled organisms are more efficient at some biochemical task is an old idea. Consider the Bioenergetic model: The amount of biomass overhead (hence sunlight energy) that is directly required for a single cell to grow and survive, is smaller than for multicelluar organisms that have evolved non-photosynthetic tissue. This is why the majority of photosynthetic primary production in the oceans is from single celled algae in phytoplankton.

 

[mfb]

The 10% is a number for the chemical pathway in plant cells, not for the whole plant system. It is a comparison between two chemical process groups.