Electrical Current Stemming From Algae

Wednesday, April 14 2010

Stanford scientists have harnessed a tiny electrical current from algae cells. They found it at the very source of energy production – photosynthesis - and it may be the first step toward generating high-efficiency bioelectricity that doesn't give off carbon dioxide as a byproduct.

"We believe we are the first to extract electrons out of living plant cells," said WonHyoung Ryu, who conducted the experiments while he was a research associate for mechanical engineering Professor Fritz Prinz.

The Stanford research team developed a unique, ultra-sharp nanoelectrode made of gold, specially designed for probing inside cells. They gently pushed it through the algal cell membranes, which sealed around it, and the cell stayed alive. From the photosynthesizing cells, the electrode collected electrons that had been energized by light and the researchers generated a tiny electrical current.

Plants use photosynthesis to convert light energy to chemical energy, which is stored in the bonds of sugars they use for food. The process takes place in chloroplasts, the cellular powerhouses that make sugars and give leaves and algae their green color. In the chloroplasts, water is split into oxygen, protons and electrons. Sunlight penetrates the chloroplast and zaps the electrons to a high energy level, and a protein promptly grabs them. The electrons are passed down a series of proteins, which successively capture more and more of the electrons' energy to synthesize sugars until all the electrons' energy is spent.