Cockroach Metabolism Unveils Rapid Plastic Breakdown

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A new study demonstrates that the cockroach Blaptica dubia can efficiently biodegrade polystyrene through a tightly integrated gut microbe–host metabolic system. The insects removed nearly 55% of ingested polystyrene within 42 days, achieving a degradation rate far exceeding those reported for other plastic-feeding insects. Analyses of residual polymer in frass versus original PS confirmed depolymerization, oxidation, enrichment of stable isotope 13C and partial mineralization.

Why it matters

Plastic pollution remains one of the most persistent environmental crises, with polystyrene (PS) among the hardest polymers to break down due to its stable aromatic backbone. This discovery expands the biological toolkit available for addressing plastic pollution and suggests that insects may possess unexpected evolutionary flexibility to adapt to anthropogenic polymers, offering a new paradigm for sustainable bioremediation.

The details

In controlled feeding experiments, cockroaches consumed an average of 6.0 mg of polystyrene per individual per day. Over 42 days, they removed 54.9% of ingested plastic, corresponding to a specific degradation rate of 3.3 mg per cockroach per day—an order of magnitude higher than rates reported in mealworms, superworms and other plastic-degrading insects. Metagenomic sequencing revealed that polystyrene feeding reshaped the gut microbiome toward plastic-degrading taxa such as Pseudomonas, Citrobacter, Klebsiella, and Stenotrophomonas, accompanied by enrichment of oxidoreductases and transferases. Network analysis showed tightly connected microbe–enzyme modules driving aromatic oxidation. Meanwhile, host transcriptomics revealed strong upregulation of β-oxidation, NADH dehydrogenase, oxidative phosphorylation, and TCA cycle pathways, indicating that microbial degradation intermediates were absorbed and metabolically integrated.

• The study was reported on February 25, 2026.