Interactions between Plastics, Microplastics, and Microbial Communities

Plastics have been an essential part of life. Each year, over 300 million tons of plastics are being processed each year into other products. However, only a small portion of the plastic gets recycled while up to 79% is discarded into landfills or directly into the natural environment. Microplastics refer to small pieces of plastic less than five millimeters long. Because of their small sizes, microplastics are able to pass through filtration systems and remain in the environment for a longer period of time, harming microorganisms, marine life, animal life, and human life. Microorganisms have the ability to transform microplastics, and there have been numerous studies on the biodegradation of bio-based and fossil based plastics. This paper approaches the interactions of microplastics and microorganisms from three main angles— biodegradation, production, and impacts— by synthesizing and analyzing known information. In particular, biodegradability is linked to physical and chemical structures, while plastic polymers can be broken down into smaller compounds which can be potentially processed through bacterial metabolism to be ultimately mineralized as CO2 . Compared to regular plastic, microplastics are more harmful and impactful to organisms (including humans), especially at the cellular level. The analysis of this paper is a good starting point for the investigation of microplastics and how microbial communities interact with them, however, it brings up further questions and gaps. Regardless, this paper highlights the significance that we devote effort and resources to better enhance the implications on ecological processes and human health.