Microbial Degradation of Plastic in Aqueous Solutions Demonstrated by CO 2 Evolution and Quantification

Int J Mol Sci. 2020 Feb 11;21(4):1176. doi: 10.3390/ijms21041176.

Abstract

The environmental accumulation of plastics worldwide is a consequence of the durability of the material. Alternative polymers, marketed as biodegradable, present a potential solution to mitigate their ecological damage. However, understanding of biodegradability has been hindered by a lack of reproducible testing methods. We developed a novel method to evaluate the biodegradability of plastic samples based on the monitoring of bacterial respiration in aqueous media via the quantification of CO2 produced, where the only carbon source available is from the polymer. Rhodococcus rhodochrous and Alcanivorax borkumensis were used as model organisms for soil and marine systems, respectively. Our results demonstrate that this approach is reproducible and can be used with a variety of plastics, allowing comparison of the relative biodegradability of the different materials. In the case of low-density polyethylene, the study demonstrated a clear correlation between the molecular weight of the sample and CO2 released, taken as a measure of biodegradability.

Keywords: Alcanivorax borkumensis; Rhodococcus rhodochrous; biodegradation; bioplastic; molecular weight; plastic; polyethylene.

MeSH terms

  • Alcanivoraceae / metabolism*
  • Biodegradation, Environmental
  • Carbon Dioxide / metabolism*
  • Environmental Monitoring / methods
  • Environmental Pollutants / metabolism*
  • Plastics / metabolism*
  • Polyethylene / metabolism
  • Refuse Disposal
  • Rhodococcus / metabolism*

Substances

  • Environmental Pollutants
  • Plastics
  • Carbon Dioxide
  • Polyethylene

Supplementary concepts

  • Alcanivorax borkumensis