Algal Mechanisms

In over 85% of plant species, the carbon dioxide (CO2) that enters a leaf is converted by the enzyme Rubisco into a carbohydrate made up of three carbon atoms, known as 3-phosphoglycerate (PGA). These plants are called C3 plants and include rice, cassava, all legumes, and wheat. Rubisco is an inefficient enzyme because it cannot distinguish between CO2 and oxygen molecules. Around 35% of the time, Rubisco binds with oxygen instead of CO2, resulting in wasted energy and reduced photosynthesis.

Cyanobacteria (blue-green algae) have overcome the limitation of Rubisco through the evolution of mini-organelles called carboxysomes, which allow the elevation of carbon dioxide around Rubisco, but requiring the participation of active molecular pumps for bicarbonate accumulation in the cell. Concentrations of carbon dioxide near the site of Rubisco are so high inside carboxysomes that oxygen cannot generally bind with the enzyme, thereby suppressing photorespiration. Photosynthesis in our crops takes place in small organelles within the cells of leaves, called chloroplasts, which evolved from cyanobacteria. Our mathematical modeling suggests that a large increase in photosynthesis could be achieved by re-engineering the active bicarbonate pumps and carboxysome structures into modern plant chloroplasts. RIPE is attempting this re-engineering, as well as sourcing bicarbonate pumps from the green micro-alga, Chlamydomonas. Many proteins are required to form carboxysomes and active pumps, making this is a particularly high-risk strategy, but one that could pay maximum dividends.

Eng Kee Au
Wei Yih (Wil) Hee
Steve Long
Ben Long
Justin McGrath
Dean Price
Loraine Rourke
Susanne von Caemmerer

Turbo-Charged Photosynthesis Could Make Crops Grow Faster While Using Fewer Nutrients

One of the great ironies of evolution is that almost all known life depends on one of the slowest and most inefficient enzymes on Earth. Now scientists have taken the largest step towards transferring a work-around from cyanobacteria into a plant.

By: IFLScience 


Crop genetic benefit two fold thanks to algae

Alge has long been known to be one of natures greatest carbon sinks, with some estimates being as high as 25% of carbon being captured into the biosphere by micro-organisms. Now researchers from The Australian National University (ANU) have engineered tiny carbon-capturing engines from blue-green algae into plants.

By: Cameron Costigan | Into the Void Science

Researchers hold tobacco plants next to growth chambers.

Algae could be crucial to boosting crop yields

Scientists have made the break through, into the way plants convert carbon dioxide, water, and sunlight into energy.

By: Eddie Summerfield | 2GB 873 AM

Jim Moroney

Missing link in algal photosynthesis found, offers opportunity to improve crop yields

Our team discovered a missing link in the photosynthetic process of green algae that could help boost crop productivity.

Team stands in greenhouse holding plant.

Blue-green algae promises to help boost food crop yields

In a breakthrough, RIPE has engineered tiny carbon-capturing engines from blue-green algae into plants to significantly boost crop yields one day.

Steve Long

Team Models Photosynthesis and Finds Room for Improvement

Teaching crop plants to concentrate carbon dioxide in their leaves could increase photosynthetic efficiency by 60 percent.