Two plant-growth-promoting Bacillus species can utilize nanoplastics

Area of Science:

• Environmental microbiology
• Bioremediation
• Agricultural science

Background:

• Plastic pollution, particularly nanoplastics, is accumulating in agricultural soils.
• These environmental plastics pose risks to human health through food contamination.
• There is a critical need for effective methods to remove plastic debris from farmlands.

Purpose of the Study:

• To investigate the potential of plant-growth-promoting bacteria to bioremediate nanoplastics.
• To assess the survival and growth of specific Bacillus species in the presence of polystyrene nanoplastics.

Main Methods:

• Two plant-growth-promoting bacterial species, Bacillus inaquosorum and B. velezensis, were exposed to polystyrene nanoplastic beads.
• Bacterial growth and survival were monitored in various media conditions, including plastic as a sole carbon source.
• Microscopic analysis was used to observe bacterial interaction with nanoplastics.

Main Results:

• Bacillus species demonstrated the ability to oxidize polystyrene nanoplastics when used as a carbon source.
• Low nanoplastic concentrations exhibited hormesis, promoting bacterial growth beyond control levels after 24 hours.
• Microscopic examination revealed bacterial cells were shielded from excessive nanoplastic accumulation.

Conclusions:

• Certain Bacillus species can utilize polystyrene nanoplastics, indicating potential for bioremediation.
• These bacteria can survive and even thrive in agricultural settings with nanoplastic contamination.
• Further development of these bacterial strains could lead to novel solutions for agricultural plastic pollution.