Last year I reported the chance discovery that the larvae of the wax moth had the ability to chew through plastic shopping bags. That was cool but the finding was limited to the animals being able to devour only a single type of plastic and did not explore what was in their poop. That matters because if the bugs are only pooping out plastics then the fact that they are eating plastic in the first place is not particularly exciting. Now a new experiment with meal worms is revealing that the bugs are capable of eating two very different types of polymers and that they very effectively biodegrade both of these materials into carbon dioxide.
The new work follows on from a series of experiments that took place three years ago and revealed that meal worms could break down polystyrene in their guts within a period of 12-15 hours. Fascinated by that, the researchers wondered whether other polymers could be put on the meal worm menu. Since global production of polyethylene is roughly four times greater than that of polystyrene and since polyethylene is the most common plastic pollutant on the planet, the team decided to try feeding that to their larvae.
The results were great. The worms were capable of degrading the polyethylene at much the same rate as they degraded polystyrene. Crucially, mass balances calculated by the researchers revealed that the worms were converting roughly 49% of the polyethylene into carbon dioxide which they reckon could be captured and put to use.
What is really important to keep in mind here is that polyethylene has a very different chemical structure to polystyrene and the fact that the meal worms devour it just as effectively as they do the polystyrene suggests that pretty much any plastic is going to prove palatable to them and, if that is ultimately proved true, then their appetite has the potential to be thoroughly harnessed. You can read more in The Economist article that I wrote on this here.