Growth kinetics and biodeterioration of polypropylene microplastics by Bacillus sp. and Rhodococcus sp. isolated from mangrove sediment

• Published in: Marine pollution bulletin Vol. 127; pp. 15 - 21
• Main Authors: Auta, H.S., Emenike, C.U., Jayanthi, B., Fauziah, S.H.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-02-2018; Elsevier BV
• Subjects: Analytical methods; Bacillus; Bacillus - isolation & purification; Bacillus sp. strain 27; Bacteria; Biodegradation; Biodegradation, Environmental; Biodeterioration; Biota; Carbon sources; Electron microscopy; Environmental impact; Environmental Monitoring - methods; Fourier transforms; Geologic Sediments - chemistry; Geologic Sediments - microbiology; Growth kinetics; Incubation period; Infrared analysis; Infrared spectroscopy; Kinetics; Malaysia; Mangroves; Marine biology; Marine organisms; Microbiological strains; Microorganisms; Microplastics; Polymers; Polypropylene; Polypropylenes - analysis; Rhodococcus; Rhodococcus - isolation & purification; Rhodococcus sp. strain 36; Scanning electron microscopy; Sediments; Spectroscopy, Fourier Transform Infrared; Water Pollutants, Chemical - analysis; Weight reduction; Wetlands; Biodegradation; Microplastics; Bacillus sp. strain 27; Polypropylene; Rhodococcus sp. strain 36
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2017.11.036

Interest in the biodegradation of microplastics is due to their ubiquitous distribution, availability, high persistence in the environment and deleterious impact on marine biota. The present study evaluates the growth response and mechanism of polypropylene (PP) degradation by Bacillus sp. strain 27 and Rhodococcus sp. strain 36 isolated from mangrove sediments upon exposure to PP microplastics. Both bacteria strains were able to utilise PP microplastic for growth as confirmed by the reduction of the polymer mass. The weight loss was 6.4% by Rhodococcus sp. strain 36 and 4.0% by Bacillus sp. strain 27 after 40days of incubation. PP biodegradation was further confirmed using Fourier-transform infrared spectroscopy and scanning electron microscopy analyses, which revealed structural and morphological changes in the PP microplastics with microbial treatment. These analyses showed that the isolates can colonise, modify and utilise PP microplastics as carbon source.
•The potential of Rhodococcus sp. and Bacillus sp. in the biodegradation of polypropylene microplastic was evaluated.•The mechanism of degradation and kinetics of growth of the bacteria isolates in microplastic-infused media were evaluated.•SEM and FTIR analysis confirmed biodegradation•The results highlight the potential of the isolates as possible tools for PP microplastic degradation.