Science Focus (issue 25)

Unleashing Nature’s Plastic-Eating Marvels! By Roshni Printer Plastic waste management has been an ongoing global challenge, demanding both urgent attention and innovative solutions. Imagine, for a moment, that nature itself had provided us with such solutions! In the fight against plastic pollution, humans have discovered the incredible ability of worms and bacteria to naturally degrade plastic waste [1]. Let’s delve into how these creatures digest plastic, the biology behind it and the future of these discoveries. Digestion of Polyethylene (PE) by Wax Worms In 2017, Federica Bertocchini and her colleagues in Spain published a ground-breaking research paper highlighting the degradation of polyethylene (PE) plastic by a wax worm, Galleria mellonella [2]. As an amateur beekeeper, Bertocchini noticed that the wax worms, which are commonly found in beehives and feed on beeswax as pests, seemed to be able to chew through plastic bags she used to collect and dispose them. Intrigued by this observation, she decided to conduct a more systematic study to further explore the potential of wax worms as a solution for plastic waste degradation. To ensure that the observation was not only due to the physical chewing motion of the worms, further experiments were conducted, in which the saliva extracted from the worms was spread on a PE film. The results showed a significant loss of mass of the PE within a few hours, which is comparable to the weathering effect generated by exposing the plastic to the environment for months or years [1]. This raised one major question: How could the wax worm saliva break the strong carbon-carbon bonds in plastic? The mechanism, which is still under scrutiny, can be attributed to enzymatic reactions [1]. PE is a plastic polymer, essentially a long-chain hydrocarbon (Figure 1). To initiate the degradation of PE, oxygen needs to be introduced into the polymeric chain to form carbonyl groups (C=O). Typically, abiotic factors like light or temperature are responsible for this crucial first step which is regarded as the bottleneck of the whole process. However, this can be accelerated by the two 出來吧!自然界蠶吃 塑膠的生物