Lessons in Photosynthesis

Lessons in Photosynthesis

photosynthesis example

This month, as I work at my desk, I get to watch the leaves on the birch and maple trees outside my window change from healthy greens to gloriously rich yellows and reds. Fall shows us the flip side of photosynthesis — the process by which deciduous trees produce fabulous amounts of energy in their chlorophyll-rich leaves by converting spring and summer sunlight, CO2, and water into delicious glucose. In the fall, waning sun and colder temperatures cause the trees to reabsorb the chlorophyll and pull nutrients down into their roots for storage till spring. This reveals the beautiful yellows that were there the entire time, just waiting for their moment! (Reds are actually anthocyanins, found in “superfoods” like blueberries, and produced by the trees as a last-gasp sunscreen to protect leaves that are slower to withdraw their nutrients.)
Scientists have tried to replicate Mother Nature’s powerhouse for a long time. If humans could replicate photosynthesis, it would mean renewable, green (pun intended) energy based on one of the most efficient models out there. A new study led by Cambridge University has just shown a more efficient and cheaper way to do exactly that, paving the way for mass use of our “nutrient,” hydrogen.
The process uses hydrogenase, an enzyme present in green algae that acts on water. The enzyme frees the hydrogen in water from its molecular bond with oxygen and allows it to be harvested. In nature, this process was deactivated in plants in evolutionary favour of traditional photosynthesis, which was more important for their survival. The Cambridge scientists have now mimicked this parallel photosynthesis with hydrogenase, for ours.
“But according to [chemist and study lead author Katarzyna] Sokół, most earlier technologies simply won’t scale up to industrial levels, either because they’re too expensive, inefficient, or use materials that pose their own risks as pollutants.

Her team’s approach was to create an electrochemical cell — not unlike a battery — based on the light-collecting biochemistry of a process called photosystem II.

This provided the necessary voltage required for the hydrogenase enzyme to do its work, reducing the hydrogen in water so it can divorce from oxygen and bubble away as a gas.”
There is still lots more research to be done, says the team, before this can be rolled out to the mass market, but its compactness and efficiency both bode well. I love looking to nature for solutions to human problems. Not only are chances good that nature’s already figured it out, but it serves as a reminder that we are part of nature too.