Sundarbans mangrove microbiota as agents for low-density polyethylene degradation

Area of Science:

• Environmental Microbiology
• Bioremediation
• Polymer Science

Background:

• Marine and terrestrial ecosystems face a crisis due to Low-Density Polyethylene (LDPE) accumulation.
• Current microbial degradation methods often require abiotic pretreatments and use terrestrial bacteria lacking resilience.
• There's a need for sustainable bioremediation strategies using robust microbial isolates.

Purpose of the Study:

• To investigate the biodegradation potential of novel bacterial strains from the Sundarbans mangrove ecosystem.
• To assess the efficacy of Bacillus tropicus SBAA01 and Pseudomonas aeruginosa SBAA02 in degrading untreated LDPE films.
• To identify resilient biocatalysts for plastic waste management.

Main Methods:

• Isolation of lipolytic bacterial strains Bacillus tropicus SBAA01 and Pseudomonas aeruginosa SBAA02 from the Sundarbans mangrove ecosystem.
• Incubation of untreated LDPE films with bacterial strains under co-metabolic conditions for 42 days.
• Analysis of LDPE degradation using weight loss measurements, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), and Carbonyl Index (CI).

Main Results:

• Bacillus tropicus SBAA01 demonstrated the highest LDPE degradation efficiency, achieving 13.63% net dry weight loss and a half-life of 198 days.
• AFM analysis showed a 736% increase in surface roughness for LDPE treated with B. tropicus SBAA01, with SEM revealing significant pitting.
• P. aeruginosa SBAA02 exhibited lower weight loss (8.89%) but significant surface disruption (142% Rq increase); B. tropicus SBAA01 maintained a moderate Carbonyl Index (0.184).

Conclusions:

• The Sundarbans mangrove ecosystem harbors stress-tolerant bacteria capable of degrading pristine LDPE without prior oxidation.
• Bacillus tropicus SBAA01 is a highly effective biocatalyst for LDPE biodegradation, offering a scalable, nature-based solution.
• These findings highlight the potential of mangrove ecosystems as a source for novel plastic-degrading microbial agents.