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Updated: May 22, 2025
Isolation of Native Soil Microorganisms with Potential for Breaking Down Biodegradable Plastic Mulch Films Used in Agriculture
Published on: May 10, 2013
Polystyrene microplastic degradation by a novel PGPR Bacillus spizizenii
Riya Chandel1, Sanya Chauhan2, Sushila Devi2
1Department of Biosciences, Himachal Pradesh University, Shimla, H.P 171005, India.
Abstract:
This study explores the novel use of Plant Growth Promoting Rhizobacteria, Bacillus spizizenii as a Polystyrene Microplastic (PS-MP) degrading agent. An impressive 85.86 % MP degradation efficiency was reported over a span of 30 days when Polystyrene (PS) was used as an exclusive carbon source. Fourier transform infrared spectroscopy (FTIR) confirmed the significant alteration in PS-MP peak intensities, indicating the breakdown of PS. Further, PS surface degradation was clearly visible in scanning electron microscopy (SEM) imaging. The metabolic analyses were performed after 30 days using Gas Chromatography-Mass Spectrometry (GC-MS). Using these metabolic data references in the KEGG database of Bacillus spizizenii potential degradation pathways were outlined. The PGPR traits of Bacillus spizizenii were confirmed by Indole Acetic Acid (IAA) Production, Phosphate solubilization, Ammonia, Hydrogen Cyanide (HCN), and Siderophore production. The results provide a novel candidate for PS degradation. The PGPR qualities further make it feasible for the use of plastic-polluted soil restoration.
Insights
Bacillus spizizenii effectively degraded 85.86% of polystyrene microplastics (PS-MP) in 30 days. This plant growth-promoting bacterium shows potential for plastic-polluted soil restoration.
Area of Science:
- Environmental Microbiology
- Bioremediation
- Polymer Science
Background:
- Plastic pollution, particularly microplastics (MPs), poses a significant environmental threat.
- Polystyrene (PS) is a common plastic polymer that is persistent and difficult to degrade.
- Bioremediation using microorganisms offers a sustainable approach to plastic waste management.
Purpose of the Study:
- To investigate the potential of Bacillus spizizenii, a plant growth-promoting rhizobacterium (PGPR), for degrading polystyrene microplastics (PS-MPs).
- To evaluate the efficiency and mechanisms of PS-MP degradation by Bacillus spizizenii.
- To assess the plant growth-promoting traits of the bacterium for potential soil restoration applications.
Main Methods:
- Cultivation of Bacillus spizizenii with Polystyrene (PS) as the sole carbon source.
- Quantification of PS-MP degradation efficiency over 30 days.
- Analysis of chemical structure changes using Fourier Transform Infrared Spectroscopy (FTIR).
- Visualization of surface morphology changes using Scanning Electron Microscopy (SEM).
- Metabolic profiling using Gas Chromatography-Mass Spectrometry (GC-MS) to infer degradation pathways.
- Confirmation of plant growth-promoting traits (IAA production, phosphate solubilization, ammonia, HCN, siderophore production).
Main Results:
- Bacillus spizizenii achieved an 85.86% degradation efficiency of PS-MPs within 30 days.
- FTIR analysis confirmed significant alterations in PS-MP peak intensities, indicating chemical breakdown.
- SEM imaging revealed clear surface degradation of PS-MPs.
- GC-MS metabolic data, when cross-referenced with the KEGG database, suggested potential degradation pathways.
- The bacterium exhibited key PGPR traits, including Indole Acetic Acid (IAA) production, phosphate solubilization, ammonia, Hydrogen Cyanide (HCN), and siderophore production.
Conclusions:
- Bacillus spizizenii is a highly effective agent for the degradation of polystyrene microplastics.
- The bacterium's ability to degrade PS-MPs and its PGPR characteristics make it a promising candidate for bioremediation of plastic-contaminated soils.
- This study presents a novel biological solution for addressing polystyrene pollution.
