Like a precious painting, the beautiful blue and green swirls of a lake or pond represent situations that should not be seen. This is due to the growth of cyanobacteria, also known as blue-green algae, which produce toxins that are toxic to humans and other animals, especially when the bloom contaminates freshwater supplies. These toxins, evolved by microbes to deter herbivores, have been linked to muscle paralysis and liver and kidney failure, as well as ALS and Parkinson’s disease. One of the toxins, anatoxin a, is very fast death factorin case you doubt its toxicity.
It seems unfortunate, then, that a highly nutritious fern called azolla (which green mallards eat in their ponds) long ago made a pact with a type of cyanobacteria called endocyanobionts. Ta. Microorganisms living inside the fern find shelter and in return supply essential nitrogen to the plant. Recently, scientists have been campaigning to turn the fast-growing Azolla into the food of the future. Some envision it becoming both a sustainable biofuel and a carbon-capturing fertilizer. But if the cyanobacteria that live inside end up being highly toxic, these ideas may not go very far.
a new paper An international research team has discovered that endocyanobionts are not typical cyanobacteria. “The cyanobacteria that live in Azolla do not produce any of these toxins, and they don’t even have the genes necessary to produce them,” said Penn State research engineer and co-author of the paper. said Daniel Winstead. “This means that one barrier to its use as food or animal feed is removed.”
This isn’t to say everyone should find their local pond, scoop up azolla, and eat them by the handful. Other research groups need to ensure that Azolla is completely non-toxic and safe for consumption before industry can develop and produce it for human consumption. Winstead’s Previous research Although some species of azolla are high in harmful polyphenols, researchers found that a species native to the southeastern United States called Carolina azolla has much lower levels, and cooking reduces them to even safer levels. Azolla is also rich in protein and nutrients such as potassium, zinc, iron, and calcium.
Azolla and its resident cyanobacteria have co-evolved a mutually beneficial relationship. Other cyanobacterial species floating in the field synthesize toxins to scare away hungry fish. “If cyanobacteria live in the azolla, they can’t produce those toxins that would otherwise kill the plant as well,” Winstead says. “So at some point, those genes were gone, which is unique among cyanobacteria.”
In exchange for providing a home for microorganisms, Azolla receives an extremely valuable resource: nitrogen. Plants need that element to grow, but not many species can extract it from the atmosphere. So-called “nitrogen fixers” such as beans and clover rely on bacteria in their roots to process nitrogen and make it available for plant growth. Endocyanobionts work similarly in Azolla, promoting growth and allowing the plant’s biomass to double as quickly as every two days.
Mr Winstead said some small farmers Already using Azolla as fertilizerand now that cyanobacteria are confirmed to be non-toxic, perhaps this technology could become widespread. With this natural source of nitrogen, farmers would be less dependent on synthetic fertilizers, which would greatly increase their production and use. greenhouse gas and pollute rivers and lakes. Azolla may also be used as livestock feed, as some farmers do already doing it If you cannot afford to feed your cattle or poultry traditional feed.
Back in the 1980s and ’90s, Chinese farmers successfully used Azolla for both purposes. They cultivated Azolla in flooded rice fields, added fish that ate the plant, and ate the fish. But it was a difficult process. Cultivation was labor-intensive, as farmers had to separate the fish before using herbicides and insecticides. When the fields ran out of water, workers mixed Azolla into the soil as fertilizer, which also required a lot of effort.
Although Azolla can fix nitrogen on its own thanks to cyanobacteria, it needed the application of phosphorus to actually grow in rice fields. “There’s no such thing as a free lunch,” says Jagdish Radha, a soil scientist and agronomist at the University of California, Davis, who was not involved in the new paper. Chinese farmers have turned to using cheaper synthetic fertilizers instead. However, the idea behind the industrialization of Azolla production is to produce the plant on a larger scale and conveniently package it as fertilizer or livestock feed.
Beyond its agricultural potential, Azolla also has the potential to become a biofuel, much like corn has been used to make biodiesel, Winstead said. That fuel will be close to carbon neutral. As plants grow, they sequester carbon. When biofuels are burned, their carbon is released into the atmosphere. By incorporating Azolla into the soil as fertilizer, farmers get even more carbon into the ground.
Humans may also form Azolla by modifying other crops such as wheat and corn, selectively breeding for the most desirable traits, such as larger grains. “It’s very possible that Azolla will go through that process,” Winstead said. Highest nitrogen fixing ability. ”
