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RACHEDI A., TABTI A., ZIGHEM A. & MAZOUZI Y. (JSBB), Volume 4, Issue 2, July 2025  
ISSN 2830-8832  
Journal Concepts in Structural Biology & Bioinformatics  
BIOTECHNOLOGY  
Research article – Review: Licence’s thesis (BSc) based.  
Bacterial Biodegradation of Plastics – Towards a  
Sustainable Solution to Plastic Pollution  
RACHEDI Abdelkrim*, 1, 2, TABTI Abdenour1, ZIGHEM Abdelrahmane1 & MAZOUZI Youcef1  
1
1
2
Department of Biology, Faculty of Natural and Life Sciences, University of Saida – Dr. Moulay Tahar  
Laboratory of Biotoxicology, Pharmacognosy and biological valorisation of plants, Faculty of Natural & Life Sciences,  
Department of Biology, University of Saida Dr. Moulay Tahar, Saida, Algeria.  
*Correspondence: abdelkrim.rachedi@univ-saida.dz  
Published: 15 July 2025  
Abstract  
The rapid expansion of plastic production and consumption, combined with limited recycling efficiency and the  
intrinsic resistance of most synthetic polymers to degradation, has resulted in the accumulation of plastic waste in  
terrestrial and marine ecosystems (Geyer et al., 2017; Lebreton & Andrady, 2019; PlasticsEurope, 2025). This  
persistent pollution poses serious environmental, ecological, and potential health risks. Conventional waste  
management strategies, including landfilling, incineration, and mechanical recycling, remain insufficient to address  
the scale of the problem and may generate secondary pollutants (Geyer et al., 2017).  
In this context, microbial biodegradation has emerged as a promising complementary strategy for mitigating  
plastic pollution. Certain bacterial taxa, notably species belonging to the genera Pseudomonas, Bacillus, and  
Enterobacter have demonstrated the ability to colonise plastic surfaces and promote polymer deterioration through  
enzymatic and oxidative processes (Shah et al., 2008; Urbanek et al., 2018). Although complete mineralisation of  
most petroleum-based plastics remains limited, significant progress has been made in understanding the  
mechanisms involved in surface modification, depolymerisation of ester-based plastics, and the role of biofilms in  
enhancing degradation efficiency (Danso et al., 2019; Wei & Zimmermann, 2017).  
This review provides a critical overview of bacterial plastic biodegradation, focusing on the types of plastics  
involved, the key bacterial species and enzymes reported in the literature, and the main limitations and future  
prospects of this emerging biotechnological approach.  
Keywords: Plastic pollution; Biodegradation; Plastic-degrading bacteria; Biofilms; Enzymes; Bioremediation  
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1. Introduction  
Plastic materials have become indispensable in modern society due to their durability, low cost, and  
versatility. However, these same properties have led to their accumulation in natural environments, where  
most synthetic polymers persist for decades or longer (Geyer et al., 2017; Lebreton & Andrady, 2019). Global  
plastic production has increased exponentially over the past decades, while recycling and recovery rates  
remain comparatively low, particularly in developing and emerging regions (PlasticsEurope, 2025). As a result,  
plastic waste has become a major environmental concern in terrestrial, freshwater, and marine ecosystems  
(Jacquin et al., 2019).  
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Biological degradation of plastics has attracted increasing scientific attention as a potential  
complementary strategy to conventional waste management approaches. Microorganisms, particularly  
bacteria, are capable of colonising plastic surfaces and inducing physicochemical changes through biofilm  
formation, oxidative reactions, and enzymatic activity (Shah et al., 2008; Urbanek et al., 2018). Although  
complete mineralisation of most petroleum-derived plastics is rare, microbial activity can contribute to  
polymer fragmentation and surface modification, thereby facilitating further degradation processes (Danso et  
al., 2019). Understanding these mechanisms is essential for assessing the realistic potential of bacterial  
biodegradation within environmental and biotechnological contexts.  
Plastics have become indispensable materials in modern society due to their low cost, durability,  
versatility, and ease of manufacture. Since the mid-twentieth century, plastic production has increased  
exponentially, replacing traditional materials such as glass, metals, and natural fibres across industrial,  
medical, agricultural, and domestic sectors. However, these same properties have rendered plastics highly  
persistent in natural environments, where they may remain for decades or even centuries.  
A substantial fraction of plastic waste accumulates in marine and coastal ecosystems, with approximately  
80% originating from terrestrial sources. Although plastic pollution has gained considerable attention in  
marine research, its ecological consequences in terrestrial systems remain comparatively underexplored. The  
resistance of synthetic polymers to biological and chemical degradation has positioned plastic pollution  
among the most pervasive global environmental challenges.  
Current mitigation strategies, including recycling and bans on certain single-use plastics, address only a  
limited proportion of total plastic waste. Consequently, alternative and complementary approaches are  
required. Microbial biodegradation, particularly by bacteria capable of colonising and modifying plastic  
surfaces, represents a promising avenue for reducing long-term plastic persistence. This review synthesises  
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current knowledge on bacterial plastic biodegradation, emphasising mechanisms, representative bacterial  
taxa, enzymatic systems, and practical limitations.  
2. Plastic Pollution and Types of Plastics  
Plastics are man-made, high-molecular-weight organic polymers derived from non-renewable  
petrochemical resources such as crude oil, natural gas, and coal. They consist of repeating monomeric units  
linked by strong covalent bonds, most commonly carbon–carbon (C–C) backbones, which confer high  
chemical stability. Their widespread adoption since the mid-twentieth century has resulted in the  
replacement of traditional materials across industrial, medical, agricultural, and domestic sectors. The  
inherent resistance of most plastics to biological and chemical degradation has positioned plastic pollution  
among the most pervasive global environmental challenges (Geyer et al., 2017). Their properties, such as light  
weight, low production cost, ease of manufacturing, bio-inertia, and resistance to environmental influence  
and microbial action, contribute to plastics’ extensive commercialization. Everyday plastic use has shown an  
exponentially increasing trend for production and consumption, reaching about 350 million tons in 2019.  
However, a sharp growth rate drop of 8.5% was registered in 2020 due to COVID-19. The production level  
before the COVID-19 pandemic in the EU27 will not be reached again until 2022. Employed in the European  
plastics industry are more than 1.56 million people in 55,000 companies with over 350 billion euros of  
turnover. As can be seen from Figure 1 (Atanasova et al., 2021), plastic producers are spread worldwide, the  
biggest contributors being Asia, Europe, and North America.  
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Figure1. Worldwide distribution of plastic producers (Atanasova et al., 2021).  
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The first synthetic polymer, Bakelite, was produced in the beginning of 20th century; the true mass  
production of plastics thrived from the 1950s onwards. Over that period, their properties have been  
continuously improved. The most widely used polymer materials are polyethylene (PE), polypropylene (PP),  
polystyrene (PS), polyvinyl chloride (PVC), polyurethane (PUR), poly(ethylene terephthalate) (PET),  
poly(butylene terephthalate) (PBT) (Tokiwa et al., 2009). Currently, more than 5300 grades are produced for  
plastic commerce with a range of chemical additives including plasticizers, pigments, stabilizers, surfactants,  
and inorganic fillers. Plastics have a wide range of applications in the industries for food and packaging,  
pharmaceuticals, agriculture, cosmetics, detergents and chemicals, Figure 2. Synthetic plastics have taken an  
impressive position in the packaging sector as a replacer of cellulose-based wrapping materials and now  
account for around 40% of the plastics produced in Europe (PlasticsEurope, 2025).  
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Figure2. Demand distribution and use of different plastics, (Atanasova et al., 2021).  
3. Principles of Plastic Biodegradation  
Bacterial biodegradation of plastics is a multi-step process that typically begins with the attachment of  
microbial cells to the polymer surface, followed by biofilm formation and extracellular enzymatic activity  
(Urbanek et al., 2018), Figure 3. The initial colonisation stage is critical, as biofilms enhance microbial  
persistence on hydrophobic plastic surfaces and create microenvironments conducive to enzymatic reactions  
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(Danso et al., 2019). Once established, bacteria secrete extracellular enzymes and oxidative agents that  
induce surface oxidation, chain scission, or hydrolysis of susceptible chemical bonds within the polymer.  
The efficiency of biodegradation is strongly influenced by polymer properties, including molecular weight,  
crystallinity, hydrophobicity, and the presence of functional groups. Plastics containing hydrolysable ester  
bonds are generally more amenable to microbial attack than polymers composed exclusively of carbon–  
carbon backbones (Wei & Zimmermann, 2017). Environmental factors such as temperature, ultraviolet  
radiation, oxygen availability, and nutrient levels further modulate degradation rates and pathways.  
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Figure 3. The outlined steps of bacterial degradation illustrate  
schematic of bacterial plastic biodegradation, highlighting the sequential steps  
from surface colonisation and biofilm development to enzymatic  
a
generalised  
depolymerisation and microbial assimilation of degradation products. This image  
has been generated for this review using AI tools.  
Biodegradation refers to the biological transformation of complex polymers into simpler chemical  
compounds through the activity of living organisms. In microbial plastic degradation, this process typically  
involves a consortium of microorganisms performing sequential roles. Primary degraders initiate surface  
modification and depolymerisation, while secondary degraders metabolise low-molecular-weight  
intermediates.  
Plastic biodegradation is influenced by multiple factors, including polymer structure, molecular weight,  
crystallinity, surface area, and the presence of functional groups such as ester or amide bonds. Environmental  
conditions, including temperature, pH, oxygen availability, and ultraviolet radiation, also play a significant  
role. Importantly, most synthetic plastics cannot be directly internalised by microbial cells; instead,  
extracellular enzymes and oxidative processes are required to initiate degradation.  
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Biodegradation is generally described as a multi-step process involving surface colonisation, biofilm  
formation, enzymatic or oxidative polymer modification, fragmentation into oligomers or monomers, and  
eventual microbial assimilation and mineralisation.  
4. Types of Plastics and Their Susceptibility to Biodegradation  
The susceptibility of plastics to bacterial degradation varies widely depending on their chemical structure  
and physical properties, Figure 4. Ester-based polymers such as poly(ethylene terephthalate) (PET), polylactic  
acid (PLA), and certain polyurethanes exhibit relatively higher biodegradability due to the presence of  
hydrolysable bonds that can be targeted by microbial enzymes (Wei & Zimmermann, 2017; Yoshida et al.,  
2016). In contrast, polyolefins such as polyethylene (PE) and polypropylene (PP) are highly resistant to  
biodegradation owing to their chemically inert carbon–carbon backbone, high crystallinity, and hydrophobic  
nature (Shah et al., 2008; Danso et al., 2019).  
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Numerous studies have reported bacterial-induced changes in polyolefin materials, including surface  
oxidation, increased brittleness, and partial fragmentation. However, these effects should be interpreted as  
ageing or weathering processes rather than true biodegradation involving complete polymer breakdown and  
mineralisation.  
Figure  
4
Comparative overview of the relative susceptibility of common  
plastics to bacterial degradation based on polymer chemistry and enzymatic  
accessibility. This image has been generated for this review using AI tools.  
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5. Plastics degrading bacteria  
A wide range of bacterial taxa have been associated with plastic surface colonisation and degradation-  
related processes. These organisms are commonly isolated from plastic-contaminated soils, landfills, marine  
environments, and insect digestive systems (Ahmed et al., 2018).  
Biodegradation is a cost-effective solution for plastic waste, using microorganisms to break down  
polymers into safer compounds through enzymatic action. The direct microbial degradation of carbon–  
carbon bonds is especially efficient, and many plastic-degrading bacterial strains have been identified, see  
Table 1.  
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Table 1. Ten (10) types of plastics degrading bacteria  
(1) PET (Polyethylene Terephthalate): A strong, lightweight plastic commonly used for  
water and soda bottles. It's durable and has good resistance to moisture.  
(2) PET/PS: A blend of PET and PS (Polystyrene), combining the clarity and strength of PET  
with the moldability of PS. It is often used in packaging.  
(3) LDPE (Low-Density Polyethylene): A flexible, lightweight plastic used for plastic bags,  
food wraps, and some types of containers. It’s known for being soft and bendable.  
(4) PE (Polyethylene): A general term for polyethylene, one of the most widely used  
plastics. It’s used in a variety of products, including bags, bottles, and pipes.  
(5) Not all types of E. coli degrade plastic, only the genetically modified ones.  
(6) PS/LDPE: A blend of PS (Polystyrene) and LDPE, which combines the rigidity of PS with  
the flexibility of LDPE. It is used in some packaging applications.  
(7) PLA (Polylactic Acid): A biodegradable plastic made from renewable resources like  
corn. It is environmentally friendly and commonly used for eco-friendly packaging.  
Bacteria  
Bacillus megaterium  
Bacillus subtilis  
Sources  
LDPE Contaminated Soil  
culture  
Plastic Types  
PET (1)  
PET/PS (2)  
LDPE (3)  
PE (4)  
Bacillus cereus  
Mangrove sediment  
Enterobacter sp. D1  
Isolated from Gut of  
Galleria mellonella  
Escherichia coli (5)  
Hydrocarbon Enriched Soil  
Landfill Soil  
LDPE (6)  
PS/LDPE  
PE  
Pseudomonas auroginosa  
Pseudomonas putida  
Pseudomonas sp. MKY1  
Garbage Soil  
Digester Sludge  
PLA (7)  
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5.1 Bacillus Species  
Species of the genus Bacillus are Gram-positive, spore-forming bacteria widely distributed in soil and  
aquatic environments. Several strains, including Bacillus megaterium, Bacillus subtilis, and Bacillus cereus,  
have been reported to promote degradation of ester-containing plastics and to induce surface deterioration  
of polyethylene films. These effects are primarily attributed to the secretion of extracellular hydrolases such  
as lipases and esterases, as well as the formation of robust biofilms that enhance enzyme–substrate  
interactions (Gajendiran et al., 2016; Xue et al., 2025).  
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5.1.1 Bacillus megaterium:  
Bacillus megaterium is a Gram-positive, spore-forming bacteria classified under the phylum Firmicutes  
and the family Bacillaceae. It thrives in diverse environments, growing optimally at temperatures between 25-  
40°C and a pH range of 6-8. This bacteria is facultatively anaerobic, allowing it to survive in both aerobic and  
anaerobic conditions [26]. Bacillus megaterium plays a crucial role in plastic biodegradation, particularly in  
breaking down polyethylene terephthalate (PET). It achieves this through the secretion of hydrolytic enzymes,  
such as polyester hydrolase, which cleaves ester bonds in plastic polymers. Additionally, it produces  
exopolymerases that degrade surface layers of plastics, facilitating further breakdown. The resulting  
degradation products are then utilized by the bacterium as carbon and energy sources. Due to these  
capabilities, Bacillus megaterium, is considered a promising candidate for bioremediation applications aimed  
at reducing plastic pollution.  
5.1.2 Bacillus subtilis:  
Bacillus subtilis, a fascinating Gram-positive bacterium, belongs to the phylum Firmicutes, nestled within  
the class Bacilli and the order Bacillales, under the family Bacillaceae. It’s quite celebrated in the world of  
biological research and industrial applications, often referred to as a model organism due to its remarkable  
versatility and resilience. This little powerhouse flourishes best in environments where the temperature  
hovers between 30 and 37°C, and the pH balances comfortably between neutral and slightly alkaline, around  
6.5 to 7.5. It prefers the company of oxygen since it’s a facultative aerobe, but what’s truly impressive is its  
ability to endure in harsh, nutrient-scarce environments by forming tough endospores[29].that can withstand  
challenging conditions. When it comes to tackling plastic waste, B. subtilis shows its impressive capabilities.  
Research has revealed that it produces a variety of enzymes, including esterases, lipases, and cutinases, all of  
which are crucial for breaking down ester bonds found in biodegradable plastics like polycaprolactone (PCL)  
and polylactic acid (PLA). Through this enzymatic action, it dismantles these plastics into smaller, more  
manageable compounds that it can feast on for carbon and energy. What’s interesting is that the efficiency  
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of this nifty biodegradation process is heightened when the conditions are just right in the conditions of  
proper aeration, optimal temperatures, and especially when these plastics are the sole source of carbon  
available. This scenario sparks the bacterium’s enzyme production, hopefully turning the course of plastic  
pollution.  
5.1.3 Bacillus cereus:  
Bacillus cereus is a Gram-positive, rod-shaped bacterium belonging to the phylum Firmicutes, class Bacilli,  
order Bacillales, and family Bacillaceae. This bacterium is notable for its ability to form endospores, which  
enables it to survive under harsh environmental conditions. Bacillus cereus can thrive in a wide range of  
environments, with optimal growth temperatures between 30°C and 37°C, although it is capable of growing  
between 4°C and 50°C. It tolerates pH levels from 4.9 to 9.3, with a preference for neutral to slightly alkaline  
conditions, and it is a facultative aerobe, meaning it can grow in both the presence and absence of oxygen.  
Regarding plastic biodegradation, Bacillus cereus has demonstrated the ability to degrade certain synthetic  
polymers, such as low-density polyethylene (LDPE) and polyurethane (PU), by producing specific enzymes like  
esterases, lipases, and hydrolases that break down the chemical bonds within the polymer chains. The  
biodegradation process involves two main steps: first, the enzymatic depolymerization of the plastic into  
smaller oligomers and monomers, followed by the microbial assimilation of these breakdown products as  
carbon and energy sources. During this process, Bacillus cereus converts the plastic-derived compounds into  
simpler substances such as carbon dioxide, water, and organic acids [38]. Notably, the efficiency of plastic  
degradation by Bacillus cereus can be enhanced through pre-treatment methods like UV irradiation or by  
employing microbial consortia that work synergistically to accelerate biodegradation. These capabilities  
position Bacillus cereus as a promising candidate for biotechnological applications aimed at addressing  
plastic pollution.  
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5.2 Pseudomonas Species  
Members of the genus Pseudomonas are metabolically versatile Gram-negative bacteria frequently associated  
with polluted environments. Pseudomonas putida, Pseudomonas aeruginosa and Pseudomonas sp. MKY1 have  
been extensively studied for their ability to degrade polyurethane and to oxidise polyethylene surfaces. Their  
metabolic flexibility allows them to utilise a wide range of xenobiotic compounds and to adapt to  
hydrophobic polymer substrates through biofilm formation and surface colonisation. Although complete  
mineralisation of polyolefins is rare, these bacteria contribute to polymer ageing and fragmentation through  
oxidative enzymes and biosurfactant production, facilitating subsequent abiotic and biotic degradation  
processes (Palleroni, 2010).  
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5.2.1 Pseudomonas putida:  
Pseudomonas putida is a Gram-negative, rod-shaped bacterium belonging to the phylum Proteobacteria  
and class Gamma proteobacteria. It is known for its ability to survive in diverse environments rich in organic  
compounds, making it an ideal candidate for environmental applications. This bacterium grows at moderate  
temperatures between 25 and 30°C, preferring a neutral pH environment (pH 6–8), and is an aerobic  
organism that relies on oxygen for its vital processes. P. putida exhibits a unique ability to degrade certain  
types of plastics, such as polyurethane, by secreting enzymes such as polyurethane esterase, which breaks  
down the chemical bonds in the polymer into smaller units. After breaking down the polymers, the bacteria  
absorb the resulting molecules and use them in their metabolic pathways for energy, producing carbon  
dioxide and water as final outputs. The importance of P. putida lies in its natural ability to tolerate polluted  
environments, as well as its ease of genetic modification to increase its efficiency in degrading plastics.  
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5.2.2 Pseudomonas aeruginosa:  
Pseudomonas aeruginosa is a species of bacteria classified under the kingdom Bacteria, phylum  
Proteobacteria, class Gammaproteobacteria, and family Pseudomonadaceae. This bacterium is highly  
adaptable to diverse environments, thriving at temperatures between 25°C and 37°C, and tolerating up to  
42°C. It is a facultative aerobe, meaning it can grow in both the presence and absence of oxygen.  
Remarkably, Pseudomonas aeruginosa demonstrates the ability to degrade certain plastics, such as  
polyurethane, by secreting enzymes like esterase and oxygenase, which break down the chemical bonds in  
plastic polymers into smaller compounds that the bacterium can utilize as sources of carbon and energy.  
Furthermore, the bacterium promotes biodegradation through oxidative processes that enhance the  
breakdown of plastic materials in natural environments.  
5.2.3 Pseudomonas sp. MKY1:  
Pseudomonas sp MKY1 is classified within the phylum Proteobacteria, class Gammaproteobacteria, order  
Pseudomonadales, family Pseudomonadaceae, and the genus Pseudomonas, which is well known for its ability  
to degrade complex compounds such as plastics. This bacterium grows under aerobic conditions, with  
optimal temperatures ranging from 30 to 37°C, and in environments with a neutral pH between 6.5 and 7.5. It  
demonstrates a remarkable capacity to utilize plastic as an alternative carbon and energy source, particularly  
in nutrient-limited environments. The plastic degradation mechanism of Pseudomonas sp. MKY1 involves  
multiple stages, beginning with the formation of a biofilm on the plastic surface, which facilitates enzyme  
interactions with the polymer. Subsequently, the bacterium secretes various extracellular enzymes, such as  
hydrolases and esterases, that break the chemical bonds in plastic polymers into smaller monomeric units.  
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These monomers are then absorbed and metabolized to generate energy or serve as building blocks for  
cellular components, ultimately converting plastic waste into environmentally friendly end products like  
carbon dioxide and water. Altogether, these properties make Pseudomonas sp. MKY1 a promising candidate  
for biotechnological applications in plastic waste bioremediation.  
5.3 Enterobacter and Related Genera  
Enterobacter species isolated from insect guts and contaminated soils have demonstrated the ability to  
degrade polyethylene under laboratory conditions, particularly when plastic serves as the sole carbon source.  
The degradation process is often enhanced by synergistic microbial communities and involves oxidative and  
hydrolytic enzymes (Ren et al., 2019).  
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5.3.1 Enterobacter sp. D1:  
Enterobacter sp. D1 is a bacterium belonging to the family Enterobacteriaceae, within the phylum  
Proteobacteria and class Gammaproteobacteria. This microorganism thrives under moderate conditions, with  
an optimal growth temperature range between 30°C and 37°C, and a preferred pH between 6 and 8, ideally  
around neutral pH (≈7). Its plastic-degrading activity is enhanced when cultured in carbon-limited media,  
where plastic polymers serve as the’sole’ carbon source.  
The biodegradation mechanism of Enterobacter sp. D1 involves the secretion of several enzymes such as  
hydrolases, which cleave chemical bonds in polymer structures; esterases, which break ester linkages; and  
oxygenases, which incorporate oxygen atoms into polymer chains, making them more susceptible to  
fragmentation. The process begins with bacterial adhesion to the plastic surface, followed by oxidative  
reactions that initiate polymer breakdown. This leads to the depolymerization of long polymer chains into  
smaller fragments, which the bacterium metabolizes as sources of carbon and energy, ultimately producing  
simple end products such as carbon dioxide, water, and new cellular biomass.  
Enterobacter sp. D1 has demonstrated promising efficiency in bioremediation applications, especially in  
plastic-contaminated environments. It has been studied for its potential to degrade various synthetic  
polymers, including polyethylene (PE) and polycaprolactone (PCL).  
5.3.2 Escherichia coli:  
Escherichia coli is classified as a Gram-negative, rod-shaped bacterium belonging to the family  
Enterobacteriaceae, naturally residing in the intestinal microbiota of humans and animals. The optimal growth  
conditions for E. coli include moderate temperatures around 37°C, a neutral pH environment (6.5–7.5), and a  
nutrient-rich medium containing glucose and essential minerals to support efficient cellular metabolism.  
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While E. coli does not inherently degrade plastics, advancements in genetic engineering have enabled the  
bacterium to express enzymes like PETase and MHETase, allowing it to break down plastics such as  
polyethylene terephthalate (PET) into environmentally benign monomers. Moreover, engineered strains have  
demonstrated the capacity to degrade complex organic pollutants, structurally similar to polymers,  
presenting a promising avenue for bioremediation applications[59]. Finally, by incorporating synthetic  
metabolic pathways, researchers have transformed E. coli into a biological chassis for plastic degradation in  
controlled industrial environments.  
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5.5 Genetically Engineered Bacteria  
Advances in synthetic biology have enabled the heterologous expression of plastic-degrading enzymes in  
model organisms such as Escherichia coli. Engineered strains expressing PETase and MHETase enzymes have  
shown significant potential for PET depolymerisation under controlled conditions, highlighting the  
importance of bioengineering in overcoming the limitations of natural biodegradation (Yoshida et al., 2016;  
Effendi et al., 2024).  
6. Plastic-Degrading Bacteria and Enzymes  
A diverse range of bacterial taxa has been associated with plastic degradation or surface modification.  
Frequently reported genera include Pseudomonas, Bacillus, Enterobacter and Rhodococcus many of which are  
known for their metabolic versatility and ability to thrive in diverse environments (Shah et al., 2008; Urbanek  
et al., 2018). These bacteria often operate within complex biofilm communities, where synergistic interactions  
may enhance degradation efficiency.  
At the molecular level, several classes of enzymes have been implicated in plastic biodegradation,  
including esterases, lipases, cutinases, and PETase-like hydrolases. The discovery of Ideonella sakaiensis and  
its PET-degrading enzymes represented a major milestone in the field, providing direct evidence of  
enzymatic PET depolymerisation under mild conditions (Yoshida et al., 2016). Subsequent structural and  
biochemical studies have further elucidated enzyme–substrate interactions, informing efforts in protein  
engineering and biotechnological optimisation (Wei & Zimmermann, 2017). Enzymes Involved in Plastic  
Degradation  
Plastic-degrading bacteria employ a range of extracellular enzymes to initiate polymer breakdown. These  
include lipases, esterases, cutinases, oxidases, and, more recently, PETase and MHETase. Ester-based plastics  
are particularly susceptible to hydrolysis by these enzymes, whereas polyolefins require initial oxidative  
modification before further degradation can occur.  
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The efficiency of enzymatic degradation is influenced by enzyme structure, substrate accessibility, and  
polymer crystallinity. Recent structural and bioinformatic studies have provided valuable insights into  
enzyme–substrate interactions, enabling the rational design and optimisation of plastic-degrading enzymes  
for biotechnological applications.  
To better understand the biochemical mechanisms employed by various bacteria in plastic  
biodegradation, it is essential to examine the specific enzymes they produce. These enzymes, including  
lipases, esterases, oxidases, and the recently discovered PETase and MHETase, play pivotal roles in catalysing  
the breakdown of complex plastic polymers into simpler, environmentally benign compounds. The diversity  
and specificity of enzymatic activity among different bacterial genera reflect their potential for targeted  
biotechnological applications in plastic waste management. Table 2 summarises the main plastic-degrading  
enzymes identified in selected bacterial strains, highlighting their role in facilitating polymer hydrolysis and  
subsequent microbial assimilation.  
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Table 2. Plastic-degrading enzymes listed per bacteria  
Bacteria  
Bacillus megaterium  
Enzymes  
Lipase, Catalase  
Bacillus subtilis  
Lipase, Protease  
Bacillus cereus  
Lipase, Esterase  
Pseudomonas putida  
Pseudomonas auroginosa  
Pseudomonas sp. MKY1  
Escherichia coli  
PETase-like enzyme, Oxidase  
Lipase, Oxidase  
PETase, MHETase  
PETase (heterologous expression)  
Protease, Lipase  
Enterobacter sp. D1  
Ochrobacterum anthropi  
Esterase  
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7. Discussion  
The growing body of literature on bacterial plastic biodegradation highlights both the promise and the  
current limitations of biological approaches to plastic waste management. While numerous bacterial species  
have been reported to interact with synthetic polymers, it is increasingly clear that the term "biodegradation"  
encompasses a wide spectrum of processes, ranging from superficial surface oxidation and biofilm-  
associated deterioration to true enzymatic depolymerisation and, in rare cases, near-complete mineralisation.  
Ester-based plastics such as poly(ethylene terephthalate) (PET) and certain polyurethanes represent the  
most realistic targets for microbial degradation, as their chemical structure provides hydrolysable bonds  
accessible to enzymes such as cutinases, esterases, and PETase-related hydrolases (Yoshida et al., 2016; Wei  
& Zimmermann, 2017). In contrast, polyolefins such as polyethylene and polypropylene remain highly  
resistant due to their inert carbon–carbon backbone, high hydrophobicity, and crystallinity. Reported  
bacterial effects on these polymers are therefore best interpreted as ageing, fragmentation, or partial  
oxidation rather than complete biodegradation (Shah et al., 2008; Danso et al., 2019).  
14  
Another important consideration is the role of microbial consortia and environmental context. In natural  
ecosystems, plastic-associated biofilms (the so-called plastisphere) consist of complex microbial communities  
whose collective metabolic activities may enhance polymer modification compared with single laboratory  
strains. However, translating these observations into scalable and controlled biotechnological processes  
remains challenging. Environmental factors such as temperature, oxygen availability, ultraviolet radiation, and  
nutrient limitation strongly influence degradation rates and outcomes.  
Recent advances in structural biology, bioinformatics, and synthetic biology provide new opportunities to  
overcome some of these limitations. Structural analyses of plastic-degrading enzymes have revealed key  
determinants of substrate binding and catalytic efficiency, enabling rational enzyme engineering and directed  
evolution approaches. Similarly, bioinformatics screening of metagenomic datasets has accelerated the  
discovery of novel plastic-active enzymes from diverse environments. These developments suggest that  
future progress in plastic biodegradation is likely to depend on integrated strategies combining microbial  
ecology, enzyme engineering, and process optimisation rather than reliance on naturally occurring strains  
alone.  
8. Limitations and Future Perspectives  
Despite encouraging laboratory results, bacterial plastic biodegradation remains a slow and incomplete  
process under natural environmental conditions. Most studies report surface erosion, weight loss, or  
fragmentation rather than full mineralisation. Consequently, biodegradation should be viewed as a  
complementary strategy rather than a standalone solution to plastic pollution (Sahith et al., 2025).  
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Future research should focus on microbial consortia, enzyme engineering, pretreatment strategies, and  
the integration of biodegradation with existing waste management systems. Advances in structural biology,  
bioinformatics, and synthetic biology are expected to play a central role in enhancing degradation efficiency  
and scalability.  
9. Conclusion  
Bacterial biodegradation of plastics represents a promising and environmentally friendly approach to  
mitigating plastic pollution, particularly as a complementary strategy to conventional waste management  
practices. While the biodegradation of ester-based plastics such as PET has been convincingly demonstrated,  
the degradation of polyolefins remains limited to surface modification and slow fragmentation. Continued  
research integrating microbiology, enzyme engineering, structural biology, and bioinformatics is essential to  
improve degradation efficiency and scalability.  
15  
Many actions are focused on addressing plastic accumulation by encouraging the active participation of  
consumers, producers, industry, and businesses. In 2016, for the first time, more plastic packaging waste was  
recycled than landfilled (EU/Norway/Switzerland). Unfortunately, landfill remains the first choice for plastic  
waste treatment in many countries. Therefore, new solutions are needed. In addition to reducing, reusing,  
and recycling plastic waste, two other considerations must be considered: energy recovery and molecular  
redesign. The latter is expected to contribute to the development and widespread application of new  
bioplastics in reducing the environmental impact of plastic. Interactions between plastics and  
microorganisms are in urgent need of further study. Biodegradation of plastic waste using plastic-degrading  
bacteria is a valuable treatment for plastic waste and must be implemented to protect environmental quality  
from the problems caused by plastic waste. This process has fewer, if any, side effects that pollute the  
environment. Plastic biodegradation involves certain hydrolases and oxidases produced by various microbes,  
including bacteria. This enzymatic process breaks down resistant plastic polymers into microbial biomass and  
other environmentally safe compounds through several steps, including surface colonization and biofilm  
formation, enzyme secretion, and absorption of degraded compounds. Optimizing suitable environmental  
conditions is the key to enhancing the ability of bacteria to degrade plastic waste.  
For regional and educational contexts, such as those targeted by our journal, the Journal of Concepts in  
Structural Biology & Bioinformatics - JSBB, bacterial plastic biodegradation offers a valuable framework for  
understanding applied environmental biotechnology and the realistic potential of biological solutions to  
global environmental challenges.  
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ISSN 2830-8832  
References  
Ahmed, T., Shahid, M., Azeem, F., Rasul, I., Shah, A. A., Noman, M., Hameed, A., Manzoor, N., Manzoor, I., &  
Muhammad, S. (2018). Biodegradation of plastics: Current scenario and future prospects for environmental  
safety. Environmental Science and Pollution Research, 25, 7287–7298. https://doi.org/10.1007/s11356-018-  
1234-9  
Atanasova, N.; Stoitsova, S.; Paunova-Krasteva, T.; Kambourova, M. Plastic Degradation by Extremophilic  
Bacteria. Int. J. Mol. Sci. 2021, 22, 5610. https://doi.org/10.3390/ijms22115610  
Danso, D., Chow, J., & Streit, W. R. (2019). Plastics: Environmental and biotechnological perspectives on  
16  
microbial  
degradation.  
Applied  
and  
Environmental  
Microbiology,  
85(19),  
e01095-19.  
https://doi.org/10.1128/AEM.01095-19  
Debroas, D., Mone, A., & Ter Halle, A. (2017). Plastics in the North Atlantic garbage patch: A boat-microbe for  
hitchhikers and plastic degraders. Science of the Total Environment, 599–600, 1222–1232.  
https://doi.org/10.1016/j.scitotenv.2017.05.059  
Effendi, S. S. W., Rahman, Hu, R., Hsiang C., Ting, W., Huang, C., Ng, I. (2024). Exploring PETase-like enzyme  
from shotgun metagenome and co-expressing Colicin E7 in Escherichia coli for effective PET degradation.  
Process Biochemistry, 140, 78–87. https://doi.org/10.1016/j.procbio.2024.03.001  
Gajendiran, A., Krishnamoorthy, S., Abraham, J. (2016). Microbial degradation of low-density polyethylene  
(LDPE) by Aspergillus clavatus strain JASK1 isolated from landfill soil. 3 Biotech. doi: 10.1007/s13205-016-  
0394-x. Epub 2016 Feb 13. PMID: 28330123; PMCID: PMC4752946.  
Geyer, R., Jambeck, J. R., & Law, K. L. (2017). Production, use, and fate of all plastics ever made. Science  
Advances, 3(7), e1700782. https://doi.org/10.1126/sciadv.1700782  
Jacquin, J., Cheng, J., Odobel, C., Pandin, C., Conan, P., Pujo-Pay, M., Barbe, V., Meistertzheim, A. L., &  
Ghiglione, J. F. (2019). Microbial ecotoxicology of marine plastic debris: A review on colonization and  
biodegradation  
by  
the  
plastisphere.  
Frontiers  
in  
Microbiology,  
10,  
865.  
https://doi.org/10.3389/fmicb.2019.00865  
Lebreton, L., & Andrady, A. (2019). Future scenarios of global plastic waste generation and disposal. Palgrave  
Communications, 5, Article 6. https://doi.org/10.1057/s41599-018-0212-7  
Palleroni, N. J. (2010). The Pseudomonas story. Environmental Microbiology, 12(6), 1377–1383.  
https://doi.org/10.1111/j.1462-2920.2009.02041.x  
PlasticsEurope. (2025). Plastics – the facts 2025: Global and European plastics production and economic  
indicators. PlasticsEurope. https://plasticseurope.org/knowledge-hub/plastics-the-fast-facts-2025/  
Sahith, V. N., Kumar, J. A., Sruthi, V. S., Sundararaman, S., Prabu, D., Venkatesan, D., & Renita, A. A. (2025).  
Bioremediation of polycyclic aromatic hydrocarbons contaminated soils/water for environmental  
remediation. Biodegradation, 37(1), 3. https://doi.org/10.1007/s10532-025-10229-y  
Shah, A. A., Hasan, F., Hameed, A., & Ahmed, S. (2008). Biological degradation of plastics: A comprehensive  
review. Biotechnology Advances, 26(3), 246–265. https://doi.org/10.1016/j.biotechadv.2007.12.005  
(Volume 4, Issue 2, July 2025)  
(JSBB) BIOTECHNOLOGY ARTICLES  
RACHEDI A., TABTI A., ZIGHEM A. & MAZOUZI Y. (JSBB), Volume 4, Issue 2, July 2025  
ISSN 2830-8832  
Tokiwa, Y., Calabia, B. P., Ugwu, C. U., & Aiba, S. (2009). Biodegradability of plastics. International Journal of  
Molecular Sciences, 10(9), 3722–3742. https://doi.org/10.3390/ijms10093722  
Ren, L., Men, L., Zhang, Z., Guan, F., Tian, J., Wang, B., Wang, J., Zhang, Y., & Zhang, W. (2019). Biodegradation  
of Polyethylene by Enterobacter sp. D1 from the Guts of Wax Moth Galleria mellonella. International journal  
of environmental research and public health, 16(11), 1941. https://doi.org/10.3390/ijerph16111941  
Urbanek, A. K., Rymowicz, W., & Mirończuk, A. M. (2018). Degradation of plastics and plastic-degrading  
bacteria in cold marine habitats. Applied microbiology and biotechnology, 102(18), 7669–7678.  
https://doi.org/10.1007/s00253-018-9195-y  
17  
Wei, R., & Zimmermann, W. (2017). Microbial enzymes for the recycling of recalcitrant petroleum-based  
plastics: How far are we? Microbial Biotechnology, 10(6), 1308–1322. https://doi.org/10.1111/1751-  
7915.12710  
Xue, H., Chen, X., Jiang, Z., Lei, J., Zhou, J., Dong, W., Li, Z., Hu, G., Cui, Z. (2025). Biodegradation of  
polypropylene by Bacillus cereus PP-5 isolated from waste landfill. Ecotoxicology and Environmental Safety  
296, 118205. https://doi.org/10.1016/j.ecoenv.2025.118205  
Yoshida, S., Hiraga, K., Takehana, T., Taniguchi, I., Yamaji, H., Maeda, Y., Toyohara, K., Miyamoto, K., Kimura, Y.,  
& Oda, K. (2016). A bacterium that degrades and assimilates poly(ethylene terephthalate). Science, 351(6278),  
1196–1199. https://doi.org/10.1126/science.aad6359  
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