Technology Transfer

Underestimating the Power of Plants

BIOLOGISTS ARE STUDYING THE ENERGY conversion processes in photosynthesis by examining space-grown protein crystals from green plants. The goal is to obtain more information on possible alternative solar power sources.

A German research team presented the results of a Space Shuttle experiment designed to crystallize Photosystem I molecules, a protein in green plants that uses trapped energy in sunlight to convert carbon dioxide into carbon and oxygen. Photosystem II protein molecules use light energy to split water into hydrogen and oxygen for plant respiration.

Previous Space Shuttle missions have shown that some protein crystals grown in the microgravity conditions of space have better order and dimension. Microgravity can also affect the rate at which the proteins initiate new growth. This Space Shuttle photosynthesis investigation is trying to discover what features of Photosystem I protein molecules allow for solar energy conversion and produce results that can improve the protein's crystallization conditions on Earth. According to the researchers, this experiment has yielded the best data set thus far obtained from Photosystem I crystals.

Photosystem I and II molecules are significant because they underlie Earth's balance between water and heat, as well as between oxygen and carbon dioxide, the building blocks of life. Earth's environments—from forests to grasslands to the oceans—are direct products of these molecules. Without them, life as we know it would not exist.

Burning carbon fuel such as oil and coal now supplies much of the world's power needs and is suspected of producing most of the excess carbon dioxide greenhouse gasses implicated in the current global warming debate. Nonpolluting alternative fuel sources are being developed to take the place of rapidly depleting oil and coal reserves. Solar power, a clean and unlimited power source, may be the most promising alternative. However, to harness and generate the Sun's power, extremely large solar panels are needed, and there is no solution for power when the Sun sets.

By identifying and studying metabolism characteristics of Photosystem I, scientists hope to develop more systems that use light as a power source and apply this information to pollution prevention and environmental cleanups. Green plants use Photosystem proteins to capture and use energy from sunlight. In photosynthesis, there are many energy-producing conversion steps from sunlight to plant development and growth.

Ancient organisms called cyanobacteria—the first oxygenic organisms to convert light to energy on Earth—were used in the space experiment. Found abundantly today, the cyanobacterium protein represents more than half the total biomass productivity in all open ocean environments and may process up to 50 percent of the excess carbon dioxide greenhouse gases implicated in the current global warming debate.

The Photosystem I experiment used the European Space Agency's Advanced Protein Crystallization Facility and is among the results recently published by NASA from the 16-day Life and Microgravity Spacelab (LMS), which flew June 20 to July 7, 1996, aboard the Space Shuttle Columbia. Its record development and cost—each experiment cost about half of most Spacelab experiments—make LMS an example of how future space station missions can control experiments remotely from locations around the globe.

For more information, contact David Noever at Marshall Space Flight Center.
Call: 256/544-7783, Fax: 256/544-1777, E-mail: David.A.Noever.Dr@msfc.nasa.gov Please mention you read about it in Innovation.