A novel bacterial combination for efficient degradation of polystyrene microplastics

Area of Science:

• Environmental Microbiology
• Polymer Science
• Biotechnology

Background:

• Polystyrene (PS) microplastics pose a significant environmental challenge.
• Microbial degradation offers a potential sustainable solution for plastic waste.
• Understanding bacterial consortia effects on PS degradation is crucial.

Purpose of the Study:

• To investigate the combined decomposition of polystyrene microplastics by three bacterial cultures: Stenotrophomonas maltophilia, Bacillus velezensis, and Acinetobacter radioresistens.
• To evaluate the efficacy of individual and combined bacterial treatments on PS microplastic biodegradation.
• To confirm biodegradation using various analytical techniques.

Main Methods:

• Cultivation of Stenotrophomonas maltophilia, Bacillus velezensis, and Acinetobacter radioresistens on PS microplastics as the sole carbon source.
• Incubation for 60 days to assess weight loss and half-life.
• Confirmation of biodegradation via scanning electron microscopy, water contact angle, high-temperature gel chromatography, Fourier transform infrared spectroscopy, and thermogravimetric analysis.

Main Results:

• Stenotrophomonas maltophilia and Bacillus velezensis achieved a maximum PS microplastic weight loss of 43.5% (half-life 74.9 days).
• Acinetobacter radioresistens showed a maximum weight loss of 16.7% (half-life 251.1 days).
• The combination of all three strains resulted in 17.0% weight loss (half-life 224.2 days), with interspecific interactions influencing degradation efficiency.

Conclusions:

• Stenotrophomonas maltophilia and Bacillus velezensis demonstrate superior PS microplastic degradation capabilities, potentially due to synergistic interactions.
• This study provides the first evidence of differential degradation by bacterial combinations on PS microplastics.
• Findings offer a valuable reference for developing mixed-bacterial biodegradation technologies for polystyrene waste.