Fungal protein shows promise for ice control in frozen foods

RESEARCHERS in the US and Germany have identified a fungal protein that could be used to control ice formation in frozen foods by triggering crystallisation at relatively high subzero temperatures. 

In a study published in Science Advances, the team discovered a molecule from fungi in the Mortierellaceae family that promotes ice nucleation – the process by which ice crystals begin to form around a particle. 

While some fungi were already known to nucleate ice, recent developments in DNA sequencing enabled the researchers to identify the specific gene responsible for producing the protein. 

Current industrial approaches typically rely on whole bacterial cells to initiate ice formation. In contrast the fungal approach requires a single protein. Boris Vinatzer, a professor at Virginia Tech’s school of plant and environmental sciences and co-author of the study, said this offers “a big advantage in food production because you have just this one well-defined protein and you can get rid of everything else”. 

Samantha Bryan, white biotechnology lead at the University of Nottingham, who was not involved in the research, told TCE the proteins also offer practical advantages. “The fact that they do not need to be membrane bound is a big advantage over the bacterial proteins,” she said. “They are also more soluble which makes them easier to purify.”

The researchers also found that the fungal protein could be expressed in both bacteria and yeast, which Bryan said, “could aid scaleup”. However, Bryan noted that only nanomolar concentrations of the protein could be obtained and significantly higher yields would be needed for industrial use. She said that while more research is needed to understand the functional properties of the protein and how to make more of it, “it’s super exciting and shows the potential for the discovery of novel proteins which can be applied to industry”.

Engineering weather

Ice nucleation is also used to increase rainfall through cloud seeding, typically done by embedding toxic silver iodide particles into clouds. The researchers believe their fungal protein approach could offer a more sustainable alternative. 

Vinatzer said: “If we learn how to cheaply produce enough of this fungal protein, then we could put that into clouds and make cloud seeding much safer.”

The study, which also involved researchers at Boise State University, the University of Utah, the Air Force Research Laboratory in Ohio and the Max Planck Institute in Germany, was funded by the US National Science Foundation, the Department of Defense and the US Air Force Office of Scientific Research.