Exploring Mycoalgae Biofilm for Nutrient Management

August 28, 2018
carlise sorenson holds up a large display with square pieces of orange biofilm.Graduate student Carlise Sorenson holds up a 2-feet by 3-feet mesh with pieces of mycoalgae biofilm to grow on. In about five days, the mesh will be completely covered and will be taken out into nutrient-rich waters in the field to adsorb phosphates and suspended solids.

Researchers are using a fungus as a cost-effective and accessible method to treat and remove excess phosphorus from natural waterways.

“This is incredibly important because phosphorus is one of the main contributors to eutrophication, an excess of nutrients in the water, which can cause oxygen depletion and toxic algal blooms,” said Carlise Sorenson, a graduate student in BBE involved in the study, led by Professor Bo Hu.

Hu and his research team developed a biofilm using the fungus Mucor indicus to adsorb phosphates and suspended solids. They are testing the dense mat of fungal growth in a contaminated body of water in the field and measuring how much phosphorus it can adsorb compared to plants.

“The bench scale tests have shown a lot of promise. This fungus adsorbs a lot of nutrients and excess sediments very quickly and easily,” Sorenson said.

In the lab, researchers first grow the fungus on multiple small cotton-polyester mesh to create the biofilm. After three to four days, a full biofilm is formed, resembling a slice of cheddar cheese. Researchers then place the pieces of biofilm onto a 2-feet by 3-feet mesh where it’ll take about five days for the fungus to grow and completely cover it. Once there’s a good layer over the mesh, it’s taken to nutrient-rich waters in the field for testing.

The biofilm mat floats in the water and is rinsed every day to wash off the biomass it collects. The biomass is measured for phosphorus, and the rinsed mat is returned to the water to be reused. After about five days in the water, the mat reaches its maximum adsorption of phosphorus, and it’s removed for data collection.

“This technology could be used in place of vegetative floating island designs to allow for more adsorption of phosphorus. Treating and preventing the accumulation of these nutrients in our waters will protect aquatic environments and species from the devastating effects of eutrophication,” Sorenson said.

The research is ongoing, and while this particular aspect of the project is complete, “we will be taking the ideas and lessons we have learned to continue discovering more in this area.”

Special thanks to post-doc Ara Rajendran who initiated the project. The Environment and Natural Resources Trust Fund (ENRTF) funded this project.