University of Florida researchers may have found a way to stop the growth of blue-green algae in freshwater across the state.
These toxic blooms usually surface in nutrient-rich freshwater during the hot summer months, killing fish and other animals. They have also been linked to health issues in people, including liver and nervous system complications.
In 2018, Florida experienced the worst blue-green algae outbreak in its history. About a year later, the Blue-Green Algae Task Force, appointed by Gov. Ron DeSantis, met for the first time to begin offering solutions to the state legislature.
Their recommendations were written into this year’s Clean Waterways Act, though some environmental groups said the legislation did not go far enough. The main focus areas were septic systems, agriculture and stormwater runoff.
Yousong Ding, an associate professor of medicinal chemistry in UF's College of Pharmacy, led a team that determined how to target a specific enzyme within blue-green algae to prevent it from growing.
Those enzymes, called dihydroxyacid dehydratase, are used by microbes and plants to produce branched-chain amino acids. All lifeforms need these amino acids to grow. Humans and animals get them from eating food, but blue-green algae can make them on their own.
The UF study found that using chemicals to block the function of the enzymes would essentially starve the cyanobacteria, which cause blooms.
This will provide an alternative way to manage blue-green algae, Ding said.
Other treatments have been reactionary, using toxic chemicals to combat existing blooms. But those treatments can make the water unsafe for people, Ding said. The prevention method has promise because it’s meant to stop a bloom from even starting, he said.
“For example, in certain lakes, or certain freshwater you know what occurred in a certain period because of past data, then you can pretreat this water body and eventually lead to better management,” he said.
Ding said his chemical technique is safe for humans and animals in the water.
“Humans and animals do not have this machinery available to produce these amino acids," he said. “Any chemicals that prevent the function of the enzymes to produce these amino acids have no effect on humans or animals.”
However, the method could affect aquatic plants, which produce their own amino acids in the same way that blue-green algae does, Ding said.
But research has shown that cyanobacteria is nearly 1,000 times more sensitive to the process than plants.
Researchers need to conduct more testing to determine how to selectively kill the one kind of cyanobacteria that causes toxic blue-green algae blooms.
They will start by observing the process in enclosed water bodies, like ponds. There’s a long way to go before they can begin using it in Florida's lakes and rivers, Ding said.
The research may actually go beyond algae growth. It can potentially help with antibiotic-resistant bacteria, as well. This occurs when bacteria evolve in response to medications and become resistant to treatments.
At least 2.8 million Americans are infected with antibiotic-resistant bacteria or fungi annually, according to the Centers for Disease Control and Prevention.
Ding is hopeful that new medicines can be developed for microbial infections, if pathogen growth can be controlled, much like cyanobacteria.
The study, called “Cyanobacterial Dihydroxyacid Dehydratases Are a Promising Growth Inhibition Target,” was recently published in the American Chemical Society’s journal Chemical Biology.
