Decomposition of Biodegradable Plastics and Microbes Associated Under Current and Future Climates

 By: Roxana Montiel

Figure: images under Scanning Electron Microscopy of the different structural changes in the surface of PBSA during different testing times, 0 days (a), 30 days (b), 180 days (c), and 328 days (d). More closed up images under SEM also showed different structural changes within the testing times, 30 days (e), 180 days (f-i), and 328 days (j-l). 

The high demand of plastics has allowed the massive accumulation of these in landfills that are affecting the terrestrial and aquatic environments. The plastic in the landfills can be broken into smaller forms called microplastics that are introduced to the environment and affect animal and human health as these are being ingested. Scientists have been researching biodegradable plastics, that will be environmental friendly, and different soil microbes that are able to degrade these. This article focuses on two things, by researching how effective are different forms of bioplastics, in particular Poly (butylene succinate-co-adipate) or PBSA, and the microbial communities that are associated in the process under natural present conditions and predicted future climates. Three climate models were applied: reduced summer precipitation by 20%, increased precipitation in spring and autumn by 10%, and increased mean temperature by 55 ℃. This treatment was observed over a period of 328 days with intervals at day 0, 30, 180, and 328.  After day 180, the PBSA film had significant structural changes that are an indication of biodegradation and after 328 days they observed that it was heavily rutted and perforated. The results also demonstrated that around 30% of mass losses of PBSA in ambient and future climate models were observed in less than a year. The microbial communities that were associated with the biodegradation of PBSA were mostly fungi and bacteria, archaea communities were also found, but they mainly served to perform nitrification. Positive correlations between the fungal and bacterial biomass were found within ambient and future climate models. The next step for this research can be the implementation of these biodegradable plastics into the different industries that rely on plastic and a more genetic depth about the degradation process of the microbes and how we can implement these genes into microbes that exist in different parts of the world and experience different climates.

Reference

Purahong, W., Wahdan Mohamed, S. F., et al. (2021). Back to the Future: Decomposability of a Biobased and Biodegradable Plastic in Field Soil Environments and Its Microbiome under Ambient and Future Climates. EST journal 55:12337-12351.