Scientists know that worms, bacteria, and various fungi can eat plants and use the vegetable cellulose as a source of carbon for their growth. Plants, on the other hand, simply sit back and photosynthesize carbon dioxide, water, and light. But now, as German researchers have discovered, algae don't always need to draw their power from the sun. Their research shows that when times get tough, some algae have no qualms about stealing energy from other plants.

The researchers, a team led by Olga Blifernez-Klassen and Olaf Kruse from Bielefeld University, made the discovery after cultivating a microscopically small green algae species called Chlamydomonas reinhardtii in a low carbon dioxide environment. The lack of CO2 was stressful for the algae as it couldn't go about photosynthesis.

But what the scientists then observed was that the single-celled plants had a backup plan; they began to tap into the energy from neighboring plants instead — essentially eating their vegetable cellulose. It was an unprecedented case of a plant eating another plant.


Chlamydomonas is able to do this by secreting enzymes that can metabolize the cellulose, breaking it down into sugars — a process that the researchers refer to as cellulose degradation and assimilation. These smaller sugary components are then transported into the cells and converted into a source of energy. So despite the lack of CO2, the algae can continue to grow and thrive.

According to Blifernez-Klassen and Kruse, this is the first time that such behavior has been confirmed in a vegetable organism — an observation that contradicts conventional notions of plant adaptability. They also suspect that other types of algae are capable of the same feat.


And interestingly, their discovery could pave the way for more efficient bioenergy production. Essentially, the algae could bypass the need to use fungus or other organisms to breakdown vegetable cellulose — what would then produce the desired cellular enzymes. Eventually, phototrophic microbes like Chlamydomonas may serve as biocatalysts for cellulosic biofuel production.

The entire study can be found at Nature Communications.

Images: Bielefeld University