Worldwide plastic production increased from 2 Million tons (Mt) in 1950 to 380Mt in 2015. In addition, recycling only means to post the future of plastic, which will ultimately be incinerated to eliminate it completely from the environment1. However, it is surprising to see more impact about new ways to get rid of it instead of reducing its production. So, should we really be that proud about another organism feeding on our waste?
Galleria Mellonella as model organism
Every now and then, we hear breaking news about organisms that could help us “digest” all the plastic waste we have produced 2. It is not surprising that we seek the solution in the smallest organism. One example could be that we have relied on them to obtain compost; produced from the oxidation of organic matter. Because of the use of microscopic (for example: bacteria) and macroscopic agents (for example: worms).
In the latter case, the news focussed on the caterpillar Galleria mellonella, a species of lepidopteran, also known because of its threat to bees3. It is a natural pest to bees because of its ability to feed on beeswax. However, it has also been described for eating plastic4. It turned out that some scientists observed how these caterpillar pierced a plastic bag and escaped. Then, they thought that this intrinsic ability of the caterpillar might be a solution to the our plastic problem.
Despite the potential of the discovery, it is still a controversy. However, it is not clear whether it will biodegrade polyethylene (PE)5 to other components or if it simply degrades the plastic in a mechanical way. Furthermore, if it were possible that this caterpillar really metabolizes PE to ethylene glycol, it must be used carefully in a controlled environment. Because of the potential toxicity of this component.
In the other hand, other example of a microorganism that is being studied is Ideonella sakaiensis, a bacteria strain that possess an enzyme called PETase 2 and could be useful in one of the steps of the recycling process.
Therefore, is clear that there is still much to study, and of course, we have to look for alternatives to process this material, but we should not forget that, for now, our hope lies in understanding how to reduce the production of plastic as well as looking for compostable alternatives .
Finally, do not forget that plastics are not so easy to recycle or degrade, due to the amount of additives they have, so it is still unclear how we could use different organisms to eliminate them. Therefore, we can not leave the future in the hands of possible organisms that will save us and not decreasing its consumption and production.
At the moment, our hope relays on the new EU legislation that is expected to be running in 2021. This claims to be a way to reduce the production of single-use plastic6 which, although is not enough, is a beginning. However, citizens can be actively part of the change, by being part of the Zero Waste movement, reducing waste and trying to find more sustainable alternatives.
- Production, use, and fate of all plastics ever made. Geyer, R.; Jambeck R.; Law K.L.. Science Advances 19 Jul 2017: Vol. 3, no. 7, e1700782; DOI: 10.1126/sciadv.1700782
- How plastic-eating bacteria actually work – a chemist explains
- Bastidas, R. y Zavala, Y. 1995. Principios de Entomología Agrícola Ediciones Sol de Barro
- Polyethylene bio-degradation by caterpillars of the wax moth Galleria mellonella
- German scientists question study about plastic-eating caterpillars
- European parliament approves sweeping ban on single-use plastics