Biodegradation of polystyrene by bacteria from the soil in common environments

Kim, Hyeong-Woo; Jo, Jin Hui; Kim, Ye-Bin; Le, Thien‐Kim; Cho, Chul-Woong; Yun, Chul‐Ho; Seok, Won; Yeom, Soo‐Jin

doi:10.1016/j.jhazmat.2021.126239

Cited by 77 publications

(29 citation statements)

References 49 publications

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“…This is particularly important when the percentage mass loss of the plastic is small (e.g. <3% as reported by Aravinthan et al (2016), Tian et al (2017), Kim et al (2021)). With this in mind, we question, have microbial abilities to degrade the most widely produced plastic polymers globally been overstated?…”

Section: Introductionmentioning

confidence: 88%

“…Critically, we could find no studies identifying enzymes that have been used to support the substantial degradation of virgin plastic polymer, or the presumed biochemical mechanisms associated with the degradation of PE, PVC, PP or PS (i.e. polymers with a C-C backbone; but see Yoon et al (2012), Bardají et al (2019), Kim et al (2021)). In contrast, multiple enzymes are linked to the degradation of PET (Yoshida et al 2016), PLA (Nakamura et al 2001), PCL (Oda et al 1997) and ester-linked PU (Gautam et al 2007, Russell et al 2011, i.e.…”

Section: Synthesismentioning

confidence: 99%

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Microbial abilities to degrade global environmental plastic polymer waste are overstated

Lear

Maday

Gambarini

et al. 2022

Environ. Res. Lett.

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Internationally, the environmental damage caused by the improper disposal of approximately 100 Mt of plastic waste per annum is of growing concern. Attempts to address this issue have generated many hundreds of scientific studies announcing the discovery of novel plastic-degrading microorganisms and their respective enzymes. On closer inspection, however, evidence remains sparse for the microbial degradation of most of the plastic polymers produced globally. We systematically surveyed the international literature to confirm how many microorganisms proposed to degrade plastics (n = 664) cause substantial (i.e.,  20% mass) losses of virgin polymer, rather than losses of plastic additives, filler, and/or shedding of polymer micro-fragments. Additionally, we noted where degradation was only demonstrated for artificially aged polymer since physicochemical ageing procedures increase the abundance of monomers and oligomers such that they may be degraded by microbial activity. Additionally, artificial ageing may introduce functional groups to the polymer backbone, creating more locations susceptible to microbial degradation than would otherwise occur in the environment. We identified multiple studies demonstrating the effective microbial degradation of heterochain plastic polymers such as polylactic acid, polycaprolactone and polyethylene terephthalate (i.e., polymers containing elements other than carbon in the backbone structure). However, in the literature, we find no evidence for the substantial degradation of unadulterated polyethylene, polypropylene, polystyrene or polyvinyl chloride, homochain polymers which represent the overwhelming majority of global plastics production. Current research demonstrates that the pre-treatment of plastics with elevated temperature or UV-light may speed physicochemical plastic degradation, with valuable applications for downstream microbial processing. However, evidence for the microbial degradation of most plastic polymers in current circulation is lacking. We outline simple criteria that should be met before announcing the microbial degradation of plastic polymers. We hope this may help to address largely unsubstantiated expectations that microorganisms can degrade many plastic polymers in situ.

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Section: Introductionmentioning

confidence: 88%

Section: Synthesismentioning

confidence: 99%

Microbial abilities to degrade global environmental plastic polymer waste are overstated

Lear

Maday

Gambarini

et al. 2022

Environ. Res. Lett.

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“…This suggests that bacteria have adapted to the conditions with MP-PS and are likely using MP-PS as a carbon source for growth. This ability of bacteria of the genera Bacillus and Pseudomonas has been investigated by other researchers [ 14 , 26 , 33 ].…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, Pseudomonas sp. was tested for PS degradation, and according to Kim et al [ 33 ], colonies of Pseudomonas sp. were observed on the PS film after 30 days.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Polystyrene Biodegradation by Bacillus cereus and Pseudomonas alcaligenes Using Full Factorial Design

et al. 2022

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Microplastics (MP) are a global environmental problem because they persist in the environment for long periods of time and negatively impact aquatic organisms. Possible solutions for removing MP from the environment include biological processes such as bioremediation, which uses microorganisms to remove contaminants. This study investigated the biodegradation of polystyrene (PS) by two bacteria, Bacillus cereus and Pseudomonas alcaligenes, isolated from environmental samples in which MPs particles were present. First, determining significant factors affecting the biodegradation of MP-PS was conducted using the Taguchi design. Then, according to preliminary experiments, the optimal conditions for biodegradation were determined by a full factorial design (main experiments). The RSM methodology was applied, and statistical analysis of the obtained models was performed to analyze the influence of the studied factors. The most important factors for MP-PS biodegradation by Bacillus cereus were agitation speed, concentration, and size of PS, while agitation speed, size of PS, and optical density influenced the process by Pseudomonas alcaligenes. However, the optimal conditions for biodegradation of MP-PS by Bacillus cereus were achieved at γMP = 66.20, MP size = 413.29, and agitation speed = 100.45. The best conditions for MP-PS biodegradation by Pseudomonas alcaligenes were 161.08, 334.73, and 0.35, as agitation speed, MP size, and OD, respectively. In order to get a better insight into the process, the following analyzes were carried out. Changes in CFU, TOC, and TIC concentrations were observed during the biodegradation process. The increase in TOC values was explained by the detection of released additives from PS particles by LC-MS analysis. At the end of the process, the toxicity of the filtrate was determined, and the surface area of the particles was characterized by FTIR-ATR spectroscopy. Ecotoxicity results showed that the filtrate was toxic, indicating the presence of decomposition by-products. In both FTIR spectra, a characteristic weak peak at 1715 cm−1 was detected, indicating the formation of carbonyl groups (−C=O), confirming that a biodegradation process had taken place.

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“…Recently, it had been reported that Acinetobacter johnsonii JNU01 and Pseudomonas lini JNU01 would be able to degrade polymeric PS. The enzymes presumably linked to the degradation are AlkB and AdhH homologues (Kim et al, 2021 ). PS biodegradation had also been reported for the microbiota of mealworms and other insects (Brandon et al, 2021 ; Kim et al, 2020 ; Peng et al, 2019 ; Yang et al, 2015b ).…”

Section: Enzymatic Degradation Of Fossil‐fuel‐derived Plastics Is Lim...mentioning

confidence: 99%

Microbial enzymes will offer limited solutions to the global plastic pollution crisis

Chow

Pérez-García

Dierkes

et al. 2022

Microbial Biotechnology

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Global economies depend on the use of fossil‐fuel‐based polymers with 360–400 million metric tons of synthetic polymers being produced per year. Unfortunately, an estimated 60% of the global production is disposed into the environment. Within this framework, microbiologists have tried to identify plastic‐active enzymes over the past decade. Until now, this research has largely failed to deliver functional biocatalysts acting on the commodity polymers such as polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC), ether‐based polyurethane (PUR), polyamide (PA), polystyrene (PS) and synthetic rubber (SR). However, few enzymes are known to act on low‐density and low‐crystalline (amorphous) polyethylene terephthalate (PET) and ester‐based PUR. These above‐mentioned polymers represent >95% of all synthetic plastics produced. Therefore, the main challenge microbiologists are currently facing is in finding polymer‐active enzymes targeting the majority of fossil‐fuel‐based plastics. However, identifying plastic‐active enzymes either to implement them in biotechnological processes or to understand their potential role in nature is an emerging research field. The application of these enzymes is still in its infancy. Here, we summarize the current knowledge on microbial plastic‐active enzymes, their global distribution and potential impact on plastic degradation in industrial processes and nature. We further outline major challenges in finding novel plastic‐active enzymes, optimizing known ones by synthetic approaches and problems arising through falsely annotated and unfiltered use of database entries. Finally, we highlight potential biotechnological applications and possible re‐ and upcycling concepts using microorganisms.

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Biodegradation of polystyrene by bacteria from the soil in common environments

Cited by 77 publications

References 49 publications

Microbial abilities to degrade global environmental plastic polymer waste are overstated

Microbial abilities to degrade global environmental plastic polymer waste are overstated

Optimization of Polystyrene Biodegradation by Bacillus cereus and Pseudomonas alcaligenes Using Full Factorial Design

Microbial enzymes will offer limited solutions to the global plastic pollution crisis

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