Living artificial leaves: Solar panel-covered ‘cyborg’ bacteria to generate the renewable fuels of the future

Scientists have developed so-called ‘cyborg’ bacteria that mimic the natural photosynthesis of leaves to renewably generate food, fuels and plastics using only sunlight.

The bacteria, which are covered in minute semiconductors that serve as tiny solar panels, function in much the same way as natural leaves, but in a far more efficient manner.

“Rather than rely on inefficient chlorophyll to harvest sunlight, I’ve taught bacteria how to grow and cover their bodies with tiny semiconductor nanocrystals,” explained Dr Kelsey K Sakimoto, who undertook the research in Dr Peidong Yang’s lab at the University of California, Berkeley. “These nanocrystals are much more efficient than chlorophyll and can be grown at a fraction of the cost of manufactured solar panels.”

The research, which is being presented today at the 254th National Meeting & Exposition of the American Chemical Society has the potential to be developed into a valuable alternative to fossil fuels.

“Once covered with these tiny solar panels, the bacteria can synthesize food, fuels and plastics, all using solar energy,” said Sakimoto. “These bacteria outperform natural photosynthesis.”

The research involved taking a natural bacterium, Moorella thermoacetica, which is not conventionally capable of photosynthesis, and feeding it chemicals that it synthesised to augment its capabilities.

As the bacterium naturally produces acetic acid from CO₂, introducing other genetically engineered bacteria can enable it to produce fuels, polymers and even pharmaceuticals. In this case, Sakimoto fed it both cadmium and cysteine, an animo acid that contains sulphur, causing the bacteria to synthesis cadmium sulphide nanoparticles on its surface: the tiny solar panels that allow it to beat leaves in photosynthesising.

“The thrust of research in my lab is to essentially ‘supercharge’ nonphotosynthetic bacteria by providing them energy in the form of electrons from inorganic semiconductors, like cadmium sulfide, that are efficient light absorbers,” explained Dr Peidong Yang. “We are now looking for more benign light absorbers than cadmium sulfide to provide bacteria with energy from light.”

Image courtesy of Kelsey K Sakimoto

While the bacteria has only been developed in a lab setting, with an 80% efficiency, if it can be developed into a commercial product, it has the potential to be a hugely impactful technology in the transition away from fossil fuels.

“Synthetic biology and the ability to expand the product scope of CO₂ reduction will be crucial to poising this technology as a replacement, or one of many replacements, for the petrochemical industry,” said Sakimoto.

Other research has been previously undertaken to produce artificial leaves, which many hope could be used to form future decentralised power plants, however this research offers a significant improvement that could give it a much higher chance of being commercialised.

“Many current systems in artificial photosynthesis require solid electrodes, which is a huge cost,” explained Sakimoto. “Our algal biofuels are much more attractive, as the whole CO₂-to-chemical apparatus is self-contained and only requires a big vat out in the sun.”

Soviet report detailing lunar rover Lunokhod-2 released for first time

Russian space agency Roskosmos has released an unprecedented scientific report into the lunar rover Lunokhod-2 for the first time, revealing previously unknown details about the rover and how it was controlled back on Earth.

The report, written entirely in Russian, was originally penned in 1973 following the Lunokhod-2 mission, which was embarked upon in January of the same year. It had remained accessible to only a handful of experts at the space agency prior to its release today, to mark the 45th anniversary of the mission.

Bearing the names of some 55 engineers and scientists, the report details the systems that were used to both remotely control the lunar rover from a base on Earth, and capture images and data about the Moon’s surface and Lunokhod-2’s place on it. This information, and in particularly the carefully documented issues and solutions that the report carries, went on to be used in many later unmanned missions to other parts of the solar system.

As a result, it provides a unique insight into this era of space exploration and the technical challenges that scientists faced, such as the low-frame television system that functioned as the ‘eyes’ of the Earth-based rover operators.

A NASA depiction of the Lunokhod mission. Above: an image of the rover, courtesy of NASA, overlaid onto a panorama of the Moon taken by Lunokhod-2, courtesy of Ruslan Kasmin.

One detail that main be of particular interest to space enthusiasts and experts is the operation of a unique system called Seismas, which was tested for the first time in the world during the mission.

Designed to determine the precise location of the rover at any given time, the system involved transmitting information over lasers from ground-based telescopes, which was received by a photodetector onboard the lunar rover. When the laser was detected, this triggered the emission of a radio signal back to the Earth, which provided the rover’s coordinates.

Other details, while technical, also give some insight into the culture of the mission, such as the careful work to eliminate issues in the long-range radio communication system. One issue, for example, was worked on with such thoroughness that it resulted in one of the devices using more resources than it was allocated, a problem that was outlined in the report.

The document also provides insight into on-Earth technological capabilities of the time. While it is mostly typed, certain mathematical symbols have had to be written in by hand, and the report also features a number of diagrams and graphs that have been painstakingly hand-drawn.

A hand-drawn graph from the report, showing temperature changes during one of the monitoring sessions during the mission

Lunokhod-2 was the second of two unmanned lunar rovers to be landed on the Moon by the Soviet Union within the Lunokhod programme, having been delivered via a soft landing by the unmanned Luna 21 spacecraft in January 1973.

In operation between January and June of that year, the robot covered a distance of 39km, meaning it still holds the lunar distance record to this day.

One of only four rovers to be deployed on the lunar surface, Lunokhod-2 was the last rover to visit the Moon until December 2013, when Chinese lunar rover Yutu made its maiden visit.

Robot takes first steps towards building artificial lifeforms

A robot equipped with sophisticated AI has successfully simulated the creation of artificial lifeforms, in a key first step towards the eventual goal of creating true artificial life.

The robot, which was developed by scientists at the University of Glasgow, was able to model the creation of artificial lifeforms using unstable oil-in-water droplets. These droplets effectively played the role of living cells, demonstrating the potential of future research to develop living cells based on building blocks that cannot be found in nature.

Significantly, the robot also successfully predicted their properties before they were created, even though this could not be achieved using conventional physical models.

The robot, which was designed by Glasgow University’s Regius Chair of Chemistry, Professor Lee Cronin, is driven by machine learning and the principles of evolution.

It has been developed to autonomously create oil-in-water droplets with a host of different chemical makeups and then use image recognition to assess their behaviour.

Using this information, the robot was able to engineer droplets to have different properties­. Those which were found to be desirable could then be recreated at any time, using a specific digital code.

“This work is exciting as it shows that we are able to use machine learning and a novel robotic platform to understand the system in ways that cannot be done using conventional laboratory methods, including the discovery of ‘swarm’ like group behaviour of the droplets, akin to flocking birds,” said Cronin.

“Achieving lifelike behaviours such as this are important in our mission to make new lifeforms, and these droplets may be considered ‘protocells’ – simplified models of living cells.”

One of the oil droplets created by the robot

The research, which is published today in the journal PNAS, is one of several research projects being undertaken by Cronin and his team within the field of artificial lifeforms.

While the overarching goal is moving towards the creation of lifeforms using new and unprecedented building blocks, the research may also have more immediate potential applications.

The team believes that their work could also have applications in several practical areas, including the development of new methods for drug delivery or even innovative materials with functional properties.