9 May 2019

Ingenious ‘control panel’ in algae provides blueprint for super-efficient future solar cells

A single ingenious protein complex makes it possible for algae and cyanobacteria to use and store solar energy more efficiently than any other organism on earth. Scientists at the universities of Utrecht and Birmingham have unravelled the mechanism, which could serve as a source of inspiration for super-efficient photovoltaic cells. They published their results in the respected scientific journal CellChem.

Like plants, algae store the sun’s energy in biomass via photosynthesis, but while plants only store an average of 12 percent of the energy, algae can store up to 98 percent. “That enormous degree of efficiency makes algae ideal for energy storage and conversion”, explains Sem Tamara, PhD Candidate at Utrecht University.

Red algae are among the most efficient energy converting organisms on Earth.

Highly complex light harvesting system

Tamara conducts research into the molecular structure that facilitates the efficient photosynthesis process in algae. A single algae has many protrusions on its surface, called antennae, which form vital components of its light harvesting system. “It’s a highly complex system. Each protrusion is made up of stacks of tiny disks. Inside each disk, there is a ‘gamma’ building block that passes the light efficiently into the system.”

Different forms of a single molecule

Tamara used mass spectrometry (MS) to discover that there may be up to 20 different types of gamma building blocks. “MS allows you to determine the weight of molecules. Each specific molecule has its own weight. The number of peaks in our mass spectrum then displays the number of different forms of a specific type of molecule.” So far, Tamara has accurately defined four different gamma building blocks. “And some of them can convert the light better than others.”

The system is more complicated than a Swiss watch. This is the product of three billion years of evolution, and engineers could learn a lot from it.
Albert Heck

Efficient through diversity

The wide diversity of molecules that let light through does not mean that one form of the light harvesting system is more efficient than another, however. According to Professor of Mass Spectrometry Albert Heck, Tamara’s PhD supervisor: “I think that the diversity of gamma building blocks is what makes the system work optimally under all circumstances. It can constantly adapt, so it is much more refined than we earlier thought.”

New generation of solar panels

Heck hopes that today’s solar panels, which have a yield of 20 percent at most, may eventually be improved with help from the same system that algae use. “The ingenious control panel that algae use to convert sunlight into usable energy is more complicated than a Swiss watch. This is the product of three billion years of evolution, and engineers could learn a lot from it. A primal organism that gives us the blueprint for the ultimate super-efficient solar cells.”

Publication

A Colorful Pallet of B-phycoerythrin Proteoforms Exposed by a Multimodal Mass Spectrometry Approach
Sem Tamara*, Max Hoek*, Richard A. Scheltema*, Aneika C. Leney and Albert J.R. Heck*
CellChem, 9 May 2019

* Affiliated with Utrecht University