A low-density polyethylene (LDPE) degrading bacterial strain (ATKU1) was isolated (99.86% similar with Bacillus siamensis KCTC 13613T) from a plastic dumping site to study interactions between microplastics (< 5 mm) and microorganisms. The strain was found (by scanning electron microscopy) to form biofilm on the microplastic surface after its interaction with LDPE (avg. Mw~4,000 Da and avg. Mn~1,700 Da) as a sole carbon source. Atomic force microscopy (AFM) showed the biofilm's 3-D developmental patterns and significantly increased Young's modulus of the LDPE surface after microbial treatment. Most of the viable bacteria attached to biofilms rather than media, which suggested their ability to utilize LDPE. Absorption bands of carbonyl, alkenyl, acyl, ester, primary-secondary alcohol, alkene groups and nitric oxides were found on the treated LDPE particles using Fourier-transform infrared spectroscopy. Fourier transform-ion cyclotron resonance mass spectrometry of the media indicated compositional shifts of the compounds after treatment (i.e., increase in the degree of unsaturation and increment in oxygen-to-carbon ratio) and presence of unsaturated hydrocarbons, polyketides, terpenoids, aliphatic/peptides, dicarboxylic acids, lipid-like compounds were hinted. The plastic degrading abilities of Bacillus siamensis ATKU1 suggest its probable application for large scale plastic bioremediation facility.
Bibliographical noteFunding Information:
This study was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (no. 2020R1A2C2009244 ). H.Y.W. is grateful for the financial support from the National Research Foundation (NRF) of Korea ( NRF-2019R1A6A1A11044070 ). Authors are thankful to Ms. Yeonjae Yoo, Division of Environmental Science and Ecological Engineering, Korea University, for her valuable suggestions regarding phylogenetic tree construction. The authors also thank Editage ( www.editage.co.kr ) for providing language editing guidance and Park Systems for their kind instrumental assistance.
© 2020 Elsevier B.V.
- Van Krevelen
ASJC Scopus subject areas
- Environmental Engineering
- Environmental Chemistry
- Waste Management and Disposal
- Health, Toxicology and Mutagenesis