Step aside solar — bacteria and prickly pears could be the future of renewable, sustainable energy, according to new research in the United States and Mexico.
Scientists have been trying to recreate photosynthesis for years and a team of scientists at the University of California, Berkeley has finally created a bacteria that can harvest sunlight better than plants. What’s more, the groundbreaking bacteria is covered in semiconductors and could be used to generate a potential fuel source from nothing more than sunlight, carbon dioxide and water.
The discovery was spurred by a review of old microbiology literature which revealed that some bacteria possess a natural defense to cadmium, mercury or lead, allowing them to convert heavy metals into a sulphide, which the bacteria express as a small, crystal semiconductor on their surfaces.
Realizing the potential this could have for improving photosynthesis efficiency, researchers began harnessing this natural ability by introducing cadmium to the bacteria during their growth stage. The bacteria then produce cadmium sulphide crystals which agglomerate on the outside of their bodies and provide them with photosynthetic capabilities.
Efficiency isn’t the only thing that has piqued scientists’ interest. The supercharged bacteria also present a low-waste alternative to more traditional biological sources of clean energy, requiring only vats of liquid and ample sunlight. Scientists speculate that this final point could make it an ideal solution for rural areas in the developing world.
But this breakthrough is just the beginning. “There are so many different designs of these systems coming out and really we’ve only begun to explore the different ways we can combine chemistry and biology. And there’s a real possibility that there will be some upstart technology that will come out that will do better than our system,” Dr. Kelsey Sakimoto, a Harvard University researcher contributing to the project told the BBC.
Meanwhile, Mexico’s symbolic prickly pear — which was once considered sacred by the ancient Aztecs — is about to add renewable energy source to its long list of uses.
While the cactus’s soft inner flesh is prized for its culinary, cosmetic and medicinal uses, its spine-studded exterior has typically been discarded as a waste product. At the cactus market in Mexico City’s Milpa Alta neighborhood alone, 10 tons of cactus end up on the floor as waste each day. Mexico City-based startup Suema recognized the opportunity the waste product presented and began exploring the potential of using a biogas generator to turn the cactus waste into energy.
The generator, which will be built right at the source of the waste — the cactus market — is expected to produce around 175 kilowatt hours when it reaches full capacity in November, enough electricity to power 9,600 energy efficient lightbulbs. The byproduct of the process could also be used as compost. If successful, the project could boost the percentage of biogas contributing to Mexico’s clean energy mix, as well as further solidify the country’s status as a climate leader.
The concept has so far been praised by the Mexican government — which has provided $840,000 in funding for the project — and members of the local farming community for its ability to provide a viable method of improving regional energy sources and create new revenue sources. Mexico City’s scientific development chief, Bernardino Rosas also hopes to reproduce the model at the more than 300 produce markets across the city.