On the Way to Green Fuels? Israeli Scientists Grow Carbon Consuming Bacteria

By Arye Green/TPS • 1 December 2019
Photo by Itzik Bellenitzki TPS

Israeli scientists of the Weizmann Institute of Science have developed bacteria that survives solely on carbon dioxide (CO2) from their surroundings, instead of their regular food. The findings point to the possible future development of carbon-neutral fuels, a significant breakthrough in the battle against climate change.

This discovery, which involved nearly a decade of molecular design, genetic engineering and an accelerated version of evolution in the lab, was reported last week in the leading scientific journal Cell.

The study began by identifying crucial genes for the process of carbon fixation, through which plants take carbon from CO2 to turn it into biomass. The research team added and rewired the needed genes to the bacteria. They also inserted a gene that allowed the bacteria to get energy from a readily available substance called formate, which can be produced directly from electricity and air.

The bacteria were gradually weaned off the sugar they were used to consuming. At each stage, cultured bacteria were given just enough sugar to keep them from complete starvation, as well as plenty of CO2 and formate.

Some “learned” to develop a taste for CO2, giving them an evolutionary edge over those that stuck to sugar, and their descendants were given less and less sugar until after about a year of adapting to the new diet some of them eventually made the complete switch, living and multiplying in an environment that only gave them pure CO2 and electricity from formate.

The researchers believe that the bacteria’s new diet could ultimately be healthy for the planet.

Professor Ron Milo, who heads the lab at the Weizmann Institute, points out that today, biotech companies use corn syrup for cell cultures to produce commodity chemicals. Such cells could be induced to live on a diet of CO2 and electricity and spare the large amounts of corn syrup they live on today.

Bacteria could be further adapted to use renewable electricity, rather than taking their energy from a substance such as formate, and then store energy for later use. Such bio-fuel would be carbon-neutral, a crucial green development in the battle against climate change.

Milo said the seemingly impossible feat could promote various future green development.

“Our lab was the first to pursue the idea of changing the diet of a normal heterotroph (one that eats organic substances) to convert it to an autotroph (‘living on air’). It sounded impossible at first, but it has taught us numerous lessons along the way, and in the end, we showed it indeed can be done,” he said.

“Our findings are a significant milestone toward our goal of efficient, green scientific applications,” he added.