Recently, a few insects, including the caterpillar larva of the greater wax moth
Galleria mellonella
, have been identified as avid ‘plastivores’. These caterpillars are able to ingest and metabolize polyethylene at unprecedented rates. While it appears that
G. mellonella
plays an important role in the biodegradation process, the contribution of its intestinal microbiome remains poorly understood and contested. In a series of experiments, we present strong evidence of an intricate relationship between an intact microbiome, low-density polyethylene (LDPE) biodegradation and the production of glycol as a metabolic by-product. First, we biochemically confirmed that
G. mellonella
larvae consume and metabolize LDPE, as individual caterpillars fed on polyethylene excreted glycol, but those excretions were reduced by antibiotic treatment. Further, while the gut bacterial communities remained relatively stable regardless of diet, we showed that during the early phases of feeding on LDPE (24–72 h), caterpillars exhibited increased microbial abundance relative to those starved or fed on their natural honeycomb diet. Finally, by isolating and growing gut bacteria with polyethylene as their exclusive carbon source for over 1 year, we identified microorganisms in the genus
Acinetobacter
that appeared to be involved in this biodegradation process. Taken collectively, our study indicates that during short-term exposure, the intestinal microbiome of
G. mellonella
is intricately associated with polyethylene biodegradation
in vivo
.
Plastic biodegradation: do Galleria mellonella larvae - bio-assimilate polyethylene? A spectral histology approach using isotopic labelling and infrared microspectroscopy.
