Bioremediation of MP-polluted Waters Using Bacteria Bacillus licheniformis, Lysinibacillus massiliensis, and Mixed Culture of Bacillus sp. and Delftia acidovorans

Dajana Kučić Grgić,Šime Ukić,Viktorija Prevarić,Vesna Ocelić Bulatović,Martina Miloloža,Marinko Markić,Matija Cvetnić,Ema Lovrinčić,Tomislav Bolanča,Antonija Kovačević,Kristina Bule

doi:10.15255/cabeq.2021.1915

Dajana Kučić Grgić, Šime Ukić + Show 9 more

Open Access

https://doi.org/10.15255/cabeq.2021.1915

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Abstract

Microplastic particles (MPs) are widely distributed pollutants in the environment. While a growing number of studies have shown that MPs are toxic to plant and animal life, systemic efforts to reduce their presence have been scarce. Low-density polyethylene (LDPE) and polystyrene (PS) are one of the most common among all plastic-forming MPs. In this study, pure bacterial strains, Bacillus licheniformis and Lysinibacillus massiliensis, and a mixed bacterial culture of Delftia acidovorans and Bacillus sp., were used for biodegradation of LDPE and PS microplastics. Biodegradation of MP-PS and MP-LDPE of particle size 300 – 500 μm was carried out under batch operating conditions at a temperature of 25 ± 2 °C, pH values of 7.15, and 160 rpm during 22 days. The obtained results showed that mixed bacterial cultures degraded MP-LDPE and MP-PS better than pure bacterial cultures, and the biodegradation efficiency was higher for MP-LDPE than for MP-PS, as indicated by greater reduction in peak intensity and spectral deformation, higher colony forming unit (CFU), and inorganic carbon (IC) values.

Highlights

Plastics are synthetic polymer materials that are among the most frequently used materials due to their versatility, durability, light weight, chemically inert behaviour, and their low-cost-production, among others[1]
Colony-forming units (CFU) of bacteria Lysinibacillus massiliensis, Bacillus sp., Bacillus licheniformis and Delftia acidovorans were determined on the general purpose media by standard plate count[55]
Microplastic particles (MPs) are most often released into the environment by the decomposition of improperly disposed plastic waste or personal care products

Summary

Introduction

Plastics are synthetic polymer materials that are among the most frequently used materials due to their versatility, durability, light weight, chemically inert behaviour, and their low-cost-production, among others[1]. Over the last 70 years, world annual plastic production has risen from 0.5 million tons to 400 million tons and is expected to double in the 20 years[2,3,4]. High demand and production of plastics has increased the amount of plastic waste in the environment, causing many prob-. MPs have become one of the leading environmental threats due to their persistence, ubiquity and intrinsic toxic potential[3]. The potential harm that MPs impose on the environment varies from direct effects (i.e., entanglement and ingestion) to their abil-

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