Texas A&M AgriLife study shows fungal isolates can remediate potentially harmful microplastics in aqueous environments.
A new study led by Texas A&M AgriLife Research has identified what may be a novel biological approach for removing tiny and potentially dangerous plastic particles from water.
The study, “Microplastics removal in the aquatic environment via fungal pelletization,” was headed by Huaimin Wang, Ph.D.. She is a post-doctoral scientist in the Texas A&M College of Agriculture and Life Sciences Department of Plant Pathology and Microbiology. Collaborators included Susie Dai, Ph.D., an associate professor in the department, and a team of researchers.
The U.S. Department of Agriculture Forest Service’s Northern Research Station also participated in the study, found online in the September edition of Bioresource Technology Reports.
“Fungal pelletization has been studied for algae harvesting and wastewater treatment in the past decade. To the best of our knowledge, it has not yet been applied for removing microplastics from an aqueous environment,” Dai said. “This study examines their use for that purpose.”
Microplastics in the environment
Microplastics have gained increasing attention in recent years due to their potential harm to the ecosystem. The continual increase in global plastic production has resulted in an increase in microplastic pollution. This persistent waste contaminant group, derived from synthetic polymers, presents a significant environmental challenge.
The health risks posed by submicrometer microplastics to humans are not yet fully understood. Those studying them generally believe the overall risk associated with submicrometer microplastics is higher than that of larger plastics. They hypothesize this is due in considerable measure to their greater potential for long-range transport and ability to more easily penetrate the cells of living organisms.
“Previous studies have indicated that submicrometer microplastics can easily travel considerable distances in the environment, infiltrating plant root cell walls,” Wang said. “They have even been shown to have been transported into plant fruiting bodies and human placenta.”
Microplastics generated from direct human activity, such as cosmetic and industrial production, are one concern. However, nanoplastics can also be generated from the fragmentation or degradation of larger plastics.
About the study
Many microplastics generated from human activities end up in sewage and wastewater treatment plants. While these plants can remove the vast majority of them, many of the submicrometer particles are unfiltered.
“The microplastics and nanoplastics removed after activated sludge treatment can be further removed by additional conventional methods,” Dai said. “But enriched microplastics still pose a waste-management challenge.”
Unfortunately, she said, some disposal methods like landfill interment or incineration are not environmentally favourable for reintroducing these back into the natural carbon cycle.
For the study, three fungal strain candidates were chosen based on their speed of growth, dye degradation, spore production and pellet formation. Two were newly isolated white rot fungi strains.
The study yielded encouraging findings on removing polystyrene and polymethyl methacrylate microplastics and nanoplastics using these isolated fungal strains.
“These microplastics and nanoplastics are among the most common,” Dai said.
The three strains showed a high rate of microplastic removal and exhibited potential microplastic assimilation.
“The microplastics attach to the surface of the fungal biomass. That makes it easier to remove them from water as part of the pellet,” Dai explained.
Wang said due to the unique capacity of the selected white rot fungal strains to form pellets. They should be suitable for remediating microplastics.
“They may also have the potential for use in upgrading wastewater treatment plants. It could be a cost-effective means to further remove microplastics and minimize the pollution by plastics in natural water bodies,” he said.
More about Dai’s studies on natural bioremediation
The current study using fungus to remove microplastics is compatible with Dai’s previous research using fungus to remediate PFAS or “forever chemicals” in the environment.
“Fungi have unique environmental applications due to their diversity and robustness,” Dai said. “They have also been useful in our ability to develop a novel bioremediation technology for these chemicals. If we do not act, it can threaten human health and ecosystem sustainability.”
PFAS are used in many applications, from food wrappers and packaging to dental floss, fire-fighting foam, nonstick cookware, textiles and electronics.
Dai’s new technology uses a plant-derived material to absorb the PFAS and dispose of them using microbial fungi that literally eat them.
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