2. An overview on biodegradation of polystyrene and modified polystyrene: the microbial approach
Ba Thanh Ho, Timothy K Roberts, Steven Lucas Crit Rev Biotechnol. 2018 Mar;38(2):308-320. doi: 10.1080/07388551.2017.1355293. Epub 2017 Aug 1.
Polystyrene is a widely used plastic in many aspects of human life and in industries due to its useful characteristics of low cost, light weight, ease of manufacture, versatility, thermal efficiency, durability, and moisture resistance. However, polystyrene is very stable and extremely hard to degrade in the environment after disposal. Polystyrene can be used as a carbon source for microorganisms similar to many other hydrocarbons. The ability of microorganisms to use polystyrene as a carbon source has been recently established. However, the high molecular weight of polystyrene limits its use as a substrate for enzymatic reactions to take place. In this paper, we review studies on biodegradation of polystyrene to give an overview and direction for future studies.
3. Polystyrene microplastic particles: In vitro pulmonary toxicity assessment
Cheng-Di Dong, Chiu-Wen Chen, Yi-Chun Chen, Hung-Hsiang Chen, Jin-Sun Lee, Chia-Hua Lin J Hazard Mater. 2020 Mar 5;385:121575. doi: 10.1016/j.jhazmat.2019.121575. Epub 2019 Nov 3.
Microplastics (MPs) have become a global environmental concern. Recent studies have shown that MPs, of which the predominant type is often polystyrene (PS; known as PS-MPs), can extend to and affect remote, sparsely inhabited areas via atmospheric transport. Although exposure to inhaled MPs may induce lung dysfunction, further experimental verification of the pulmonary toxic potential of MPs and the mechanism underlying the toxicity is needed. Here we used normal human lung epithelial BEAS-2B cells to clarify the association between pulmonary toxicity and PS-MPs. Results revealed that PS-MPs can cause cytotoxic and inflammatory effects in BEAS-2B cells by inducing reactive oxygen species formation. PS-MPs can decrease transepithelial electrical resistance by depleting zonula occludens proteins. Indeed, decreased α1-antitrypsin levels in BEAS-2B cells suggest that exposure to PS-MPs increases the risk for chronic obstructive pulmonary disease, and high concentrations of PS-MPs can induce these adverse responses. While low PS-MP levels can only disrupt the protective pulmonary barrier, they may also increase the risk for lung disease. Collectively, our findings indicate that PS-MP inhalation may influence human respiratory health.
