Scientists discover beetle larvae that can biodegrade plastic

Scientists claim to have identified a species of darkling beetle larvae found in Korea that can digest and decompose polystyrene in their gut.

A joint research team at Pohan University of Science and Technology (POSTECH) has found that the larvae of the beetle Coleoptera (P. davidis), indigenous to East Asia, can consume polystyrene and reduce both its mass and molecular weight.

Polystyrene is known to be difficult to decompose due to its unique molecular structure and the scientists believe their discovery may help solve the issue of plastic waste.

With their findings published in Applied and Environmental Microbiology, the team also confirmed that the larvae’s isolated gut flora could oxidise and change the surface property of the polystyrene film.

The scientists isolated and identified Serratia bacteria from the intestinal tract of the larvae. After feeding polystyrene to the larvae for two weeks, the proportion of Serratia in the gut flora was said to have increased by six-fold.

According to the study, the unique diet of the darkling beetle larvae that was uncovered presents the possibility that polystyrene can be broken down by other insects that feed on rotten wood.

The scientists also anticipate the development of an effective polystyrene-decomposing flora using the bacterial strains found in the simple gut flora of P. davidis.

One of the authors of the study, Professor Hyung Joon Cha, said: “We have discovered a new insect species that lives in East Asia – including Korea – that can biodegrade plastic through the gut flora of its larvae.

“If we use the plastic-degrading bacterial strain isolated in this study and replicate the simple gut floral composition of P. davidis, there is the chance that we could completely biodegrade polystyrene, which has been difficult to completely decompose, to ultimately contribute to solving the plastic waste problem that we face.”

Earlier this year, scientists working for industrial chemistry firm Carbios discovered an enzyme which can reportedly break down PET plastics for recycling into food-grade material in hours, rather than weeks.