Soil fauna Protaetia brevitarsis mediated polyethylene microplastic biodegradation

Area of Science:

• Environmental Science
• Microbiology
• Ecology

Background:

• Polyethylene (PE) microplastics (MPs) are persistent soil contaminants, primarily from agricultural mulch films.
• Conventional degradation methods are insufficient, necessitating novel bioremediation strategies.

Purpose of the Study:

• To investigate the potential of soil-dwelling grubs (Protaetia brevitarsis larvae) to biodegrade PE microplastics.
• To elucidate the role of gut microbes in the PE microplastic degradation process.
• To assess the feasibility of using P. brevitarsis for in situ remediation of agricultural plastic pollution.

Main Methods:

• Experimental exposure of P. brevitarsis larvae to PE microplastics over 28 days.
• Quantification of PE mass reduction and molecular analysis (molecular weight, functionalization, thermal profiles) of degraded MPs.
• Antibiotic treatment to assess microbial contribution and gut microbiota profiling.

Main Results:

• P. brevitarsis larvae consumed significant amounts of PE MPs, achieving a 28.6% mass reduction.
• Degraded MPs exhibited reduced molecular weight and oxidative functionalization, indicating depolymerization.
• Gut microbiota shifted to Enterococcaceae-dominated consortia, crucial for polymer breakdown; larvae maintained survival and growth.

Conclusions:

• P. brevitarsis larvae, in synergy with their gut microbiota, can effectively biodegrade ultrahigh molecular weight PE microplastics.
• This study demonstrates the first instance of PE-MP biodegradation by P. brevitarsis, highlighting their potential as natural bioremediators.
• P. brevitarsis offers a sustainable, in situ solution for mitigating agricultural PE-MP pollution with minimal ecological impact.