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Plastic is a general term used for a wide range of high molecular weight organic polymers obtained mostly from the various hydrocarbon and petroleum derivatives. There is an ever-increasing trend towards the production and consumption of plastics due to their extensive industrial and domestic applications. However, a wide spectrum of these polymers...
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Plastic waste is an issue of global concern because of the environmental impact of its accumulation in waste management systems and ecosystems. Biodegradability was proposed as a solution to overcome this problem; however, most biodegradable plastics were designed to degrade under aerobic conditions, ideally fulfilled in a composting plant. These n...
Black polyethylene (PE) is the most common mulching material used in horticultural crops in the world but its use represents a very serious environmental problem. Biodegradable films and paper mulches are available alternatives but farmers are reluctant to adopt them because of their high market prices. The aim of this paper is to evaluate the econ...
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... Within this collection of gene clusters, the pca CP018063 and CP018064 enzymes present in Rhodococcus sp. are particularly noteworthy (Zhao et al. 2018). Finally, after a series of mineralization processes that supply carbon source materials essential for microbial growth and reproduction, small molecules undergo hydrolysis and mineralization, resulting in the formation of water, carbon monoxide, methane, and carbon dioxide in both oxygen-rich and oxygen-poor environments (Fig. 2) (Ahmed et al. 2018). The presence of speciesspecific decomposing enzymes within a singular bacterial system results, on one hand, in the generation of diverse intermediate compounds that could potentially be toxic. ...
Phthalic acid esters are widely used worldwide as plasticizers. The high consumption of phthalates in China makes it the world’s largest plasticizer market. The lack of phthalic acid ester’s chemical bonding with the polymer matrix facilitates their detachment from plastic products and subsequent release into the environment and causes serious threats to the health of living organisms. Thus, environmentally friendly and sustainable solutions for their removal are urgently needed. In this context, both natural and engineered bacterial and algal communities have played a crucial role in the degradation of various phthalic acid esters present in water and soil. When algae-bacteria co-culture is compared to a singular algae or bacteria system, this symbiotic system shows superior performance in the removal of dibutyl phthalates and diethyl phthalates from synthetic wastewater. This review provides an optimistic outlook for co-culture systems by in-depth examining single microorganisms, namely bacteria and algae, as well as algae-bacterial consortiums for phthalates degradation, which will draw attention to species co-existence for the removal of various pollutants from the environment. In addition, further development and research, particularly on the mechanisms, genes involved in the degradation of phthalic acid esters, and interactions between bacterial and algal species, will lead to the discovery of more adaptable species as well as the production of targeted species to address the environmental pollution crisis and provide a green, efficient, and sustainable approach to environmental protection. Discrepancies in knowledge and potential avenues for exploration will enhance the existing body of literature, enabling researchers to investigate this field more comprehensively.
Graphical abstract
... iii) Assimilation is a biological phenomenon characterised by the integration of molecules to generate energy and the production of new biomass and various metabolic processes. iv) Polymer is converted to CO 2 , water and other metabolic by-products through mineralisation to reach a state of complete degradation (Ahmed et al., 2018;Wu et al., 2019). Bacteria, fungi and actinomycetes can degrade microplastics (Yuan et al., 2020). ...
... Rhamnolipid-based biosurfactants can degrade several plastic polymers like polystyrene foam, and polyethylene. The ability of biosurfactants to degrade plastic is due to the presence of several functional groups because they help the biosurfactant to be effective in different environmental conditions [143]. Degradation of organic contaminants is very difficult because they are mostly hydrophobic in nature and they have a very high interfacial tension. ...
Biosurfactants are amphipathic molecules produced by bacteria, yeast, and fungi as secondary metabolites. Several microbes including Candida, Pseudomonas, Bacillus, Mycobacterium, and Acinetobacter, are known to produce biosurfactants. Researchers have recently focused on biosurfactants due to their potential therapeutic, industrial, and environmental applications. They are useful in wide range of applications such as antimicrobial, anti-biofilm, anticancer treatments, oil recovery, bioremediation, phytoremediation, food processing, and hydrocarbon degradation. Due to the overuse and misuse of broad-spectrum antibiotics, there is a continuous rise of multidrug-resistant bacteria. Biosurfactants may be viable replacements to standard antibiotics in this context, and their prospective uses in biomedical science may be a bright spot in the post-antibiotic era. Biosurfactants are widely applied as drug delivery systems and coating agents. Biosurfactants have various advantages over chemical surfactants including greater biodegradability, low toxicity, high specificity, eco-friendly properties, and working ability at a wide range of temperatures, pH values, and salinities. Research is being conducted to screen strains with higher biosurfactant-producing abilities and engineered microbes are also used to increase the yield. Some actinobacterial strains such as Rhodococcus can also produce trehalolipid biosurfactants as secondary metabolites. Actinobacterial biosurfactants are useful for bioremediation and the cosmetic industry. In the case of biosurfactant production; cheaper substrates such as waste raw materials can be utilized. The major limitation of using biosurfactants is that their production cost is much higher than that of chemical surfactants, and downstream processing is also difficult. In this review, the most recent applications of biosurfactants are summarized and discussed.
... Plastics are long-chain synthetic polymers composed of various organic compounds derived mainly from coal, natural gas and oil (Barnes et al. 2009, Ahmed et al. 2018, Rodríguez et al. 2020, Amobonye et al. 2021. Plastics are widely used in daily life and in different industries, which has led to their massive production since the 1950s, and each year their production increase, so that in 2015 were produced more than 400 million tons, and it is expected that this number will double by 2035. ...
... However, plastics are difficult to degrade because their chemical composition gives them a very stable structure, preventing them from quickly entering the biosphere's degradation cycles (Ahmed et al. 2018, Wierckx et al. 2018, Jaiswal et al. 2020). Furthermore, plastic waste is often mishandled, resulting in its presence in various environments such as soil, sediments, and the water column of rivers, lakes, and oceans, leading to the accumulation of plastics in these locations, and environmental pollution problems (Barnes et al. 2009, Ahmed et al. 2018, Ganesh-Kumar et al. 2020). ...
... However, plastics are difficult to degrade because their chemical composition gives them a very stable structure, preventing them from quickly entering the biosphere's degradation cycles (Ahmed et al. 2018, Wierckx et al. 2018, Jaiswal et al. 2020). Furthermore, plastic waste is often mishandled, resulting in its presence in various environments such as soil, sediments, and the water column of rivers, lakes, and oceans, leading to the accumulation of plastics in these locations, and environmental pollution problems (Barnes et al. 2009, Ahmed et al. 2018, Ganesh-Kumar et al. 2020). In addition, microplastics (pieces of plastic smaller than 5 mm in size) pose a greater risk than larger plastics because they are more easily transported by water or wind, accumulate more in different environments, and affect ecosystems and living organisms in different ways (Ogunola et al. 2018, Kutralam-Muniasamy et al. 2020, Du et al. 2021, Zhang et al. 2021. ...
Microplastics cause pollution problems because they are difficult to degrade and tend to be easily transported and accumulate in the environment. Biodegradation is a promising solution by exploiting the ability of fungi or bacteria to accelerate the degradation process of microplastics, but this is a topic with several knowledge gaps. To evaluate the ability of microorganisms to degrade high-density polyethylene microplastics, four bacterial strains isolated from a sanitary landfill were selected, in a minimal salt medium with microplastics as the sole carbon source. The selected strains were identified as Tsukamurella sp. strain JP3, Tsukamurella sp. strain JP5+, Pseudomonas aeruginosa (JP5–) and Streptomyces sp. strain JP8. The bioassays were performed with single strains and mixed cultures. Biodegradation was determined by calculating the percentage weight loss of the microplastics and observing changes in their surface structure using scanning electron microscopy (SEM). Biodegradation rates between 6.81 and 18.14% were obtained, with JP5+JP8 being the treatment with the highest percentage, but with no significant differences between treatments. However, SEM showed microbial damage and growth on the surface of microplastics. Therefore, the bacterial strains used would have potential for biodegradation of high-density polyethylene, but it is advisable to continue investigations to determine the conditions and appropriate times to improve biodegradation with these strains.
... They accrued in the environment and became a threat. Some of them are chemically inactive and resistant to microbial attack [17]. The term "Bio" in bio-based polymers stands for carbon source or its biodegradability. ...
... Bacterial cells employ these monomers as an energy and carbon source. This process includes both aerobic and anaerobic processes [17]. Certain petroleum-based polymers are also biodegradable. ...
Plastic is composed of synthetic and semi-synthetic compounds with immense applications. While Plastics are dangerous and harm the environment, their practice is causing their ingesting to grow. Outdated methods of plastic degradation through physical and chemical means like landfill, incineration, and recycling are expensive and perilous and release hazardous chemical substances to the environment. Thus, proper approaches are required to overcome this trick. Biodegradation through microbes on the other hand offers a hopeful solution. Presently, numerous categories of bacteria and other microbial species degrade plastic materials. Several steps are required in plastic biodegradation like biodeterioration, depolymerization, assimilation and mineralization. These processes will result in secretion of enzymes that degrade plastics and converts it into gasses and biomass along other biproducts.
... Microbial biodegradation offers a promising solution for addressing marine and terrestrial microplastic pollution, as conventional methods-such as landfilling, incineration, and recycling-are ineffective at removing widely dispersed microplastics (44). However, its commercial viability is currently limited by factors such as low degradation efficiency and the need to account for variables including the biochemical composition of the plastic, temperature, pH, oxygen availability, potential pathogenic risks, and overall environmental safety (23,45,46). So far, a few isolated microorganisms have successfully degraded polyethylene terephthalate (PET) and blended textiles (47,48), and ongoing research is expanding to target other plastic types. ...
In this study, we present Methylobacterium aquaticum A1, a novel strain capable of degrading polyester polyurethane (PE-PUR). The attachment of M. aquaticum A1 to PE-PUR and its degradation capabilities were verified using Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FT-IR). Analysis of the reference genome of M. aquaticum revealed genes encoding enzymes with potential PE-PUR degrading activity, including esterases, lipase, proteases and amidase such as tesA , pgpB , aes , aprE , lon , degQ, and gatA . An esterase activity assay using p -nitrophenyl acetate ( p -NPA) showed increased ester bond-cleaving activity when M. aquaticum A1 was exposed to polyurethane diol (PU-diol), suggesting inducible enzymatic activity involved in PE-PUR degradation. These findings highlight the potential of M. aquaticum A1 as a promising biocatalyst for PE-PUR degradation.
IMPORTANCE
Microbial biodegradation is increasingly recognized as a sustainable approach to addressing microplastic pollution. This study introduces M. aquaticum A1, a newly isolated strain capable of adhering to and degrading polyester polyurethane (PE-PUR), one of the most widely utilized plastics. To our knowledge, this is the first report of PE-PUR degradation by a member of the Methylobacterium genus. This paper provides a detailed characterization of M. aquaticum A1 and identifies several enzyme candidates— tesA , pgpB , aes , aprE , lon , degQ, and gatA —as potentially involved in the degradation process. Given that Methylobacterium species are known to be ecologically beneficial and inhabit diverse environments, the capacity of M. aquaticum A1 to degrade PE-PUR presents a promising strategy for mitigating microplastic pollution across a range of ecosystems.
... They are composed of various polymers, including polyhydroxybutyrate (PHB), polyhydroxyvalerate (PHV), and copolymers with different monomeric units. PHAs have various properties, including biocompatibility, biodegradability, and thermoplastic behavior, and can be processed using conventional polymer techniques (20). They are used in packaging, biomedical devices, agriculture, and consumer goods, including compostable bags, food packaging, disposable tableware, sutures, drug delivery systems, and agricultural mulch films. ...
The environmental impact of conventional plastics has spurred the development of biodegradable, recyclable, and renewable polymers as sustainable alternatives. Biodegradable, recyclable, and renewable polymers are developing as viable alternatives to standard petroleum-based plastics due to their environmental benefits and sustainability. These polymers can be manufactured using renewable sources such as plants and microbes, reducing reliance on fossil fuels and minimizing plastic pollution. Biodegradable polymers offer end-of-life solutions through composting or natural breakdown, reducing plastic pollution. Recyclable biopolymers can be processed into new products, minimizing waste. Renewably sourced polymers utilize biomass, a natural resource, to lessen dependence on fossil fuels. These polymers, derived from renewable resources such as plant-based materials, agricultural by-products, and microbial fermentation, offer several advantages over conventional plastics, including reduced environmental impact, decreased dependence on fossil fuels, and enhanced end-of-life options.
... The pH can be altered to change the rate of the hydrolysis reaction by changing the acidic or alkaline conditions. Degradation products of various polymers alter the pH conditions and subsequently change the rate of the degradation process and microbial growth [49]. Therefore, we explored the weight loss rate of PE/PP MPs by the four potentially efficient PE/PP microplastic-degrading bacteria under different pH conditions, and they were significantly different ( Figure 3C). ...
With the rapid growth of global plastic production, the degradation of microplastics (MPs) has received widespread attention, and the search for efficient biodegradation pathways has become a hot topic. The aim of this study was to screen mangrove sediment and surface water for bacteria capable of degrading polyethylene (PE) and polypropylene (PP) MPs. In this study, two strains of PE-degrading bacteria and two strains of PP-degrading candidate bacteria were obtained from mangrove, named Pseudomonas sp. strain GIA7, Bacillus cereus strain GIA17, Acinetobacter sp. strain GIB8, and Bacillus cereus strain GIB10. The results showed that the degradation rate of the bacteria increased gradually with the increase in degradation time for 60 days. Most of the MP-degrading bacteria had higher degradation rates in the presence of weak acid. The appropriate addition of Mg2+ and K+ was favorable to improve the degradation rate of MPs. Interestingly, high salt concentration inhibited the biodegradation of MPs. Results of scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier-transform infrared spectroscopy (FTIR) indicated the degradation and surface changes of PP and PE MPs caused by candidate bacteria, which may depend on the biodegradation-related enzymes laccase and lipase. Our results indicated that these four bacterial strains may contribute to the biodegradation of MPs in the mangrove environment.
... Plastic-degrading microorganism process is a further area of research for wastewater treatment (Ahmed et al. 2018;Ebrahimbabaie et al. 2022). Microorganisms have been proven to degrade plastics, indicating that microbial metabolic pathways of plastic depolymerization is an innovative recycling method to dispose of plastic waste. ...
Plastic is a material that has become ubiquitous since entering the marketplace in the 1930s and 1940s; as a result, the presence of nano and microplastics (NMPs) are pervasive in natural environments affecting air, soil and water ecosystems. These NMPs are varied in size (categorised as either microplastics at 5 mm–1 µm or nanoplastics at < 1 µm), shape and chemical composition. They represent a potential threat to aquatic life and human health through ingestion and inhalation. The toxicity of NMPs is attributed to chemical additives introduced during production and the absorbance of inorganic and organic chemical contaminants in environmental settings. This review is designed to discuss the use of biochar as a natural adsorbent for the remediation of water contaminated with NMPs. Biochar is a sustainable, affordable material which can remediate water and contribute to ecosystem restoration. Whilst it is well established as a material to sorb organic and inorganic contaminants, its use to remove NMPs is in its infancy and as such this review sets out to outline the mechanisms and modifications of biochar to remove NMPs from aqueous environments. Although removal mechanisms in laboratory settings are becoming clearer this review highlights that remediative studies need to be undertaken in conjunction with the systematic investigation of the effect of key environmental parameters on remediation and the use of environmentally aged NMPs. The future direction of this discipline also needs to incorporate field trials alongside laboratory work to develop a stronger understanding of the viability of biochar to remove NMPs from waterways.
... These act like low-density polyethylene but contain chemical pro-oxidants that facilitate breakdown through oxidation in the presence of light. During photo-oxidation, the polymer's molecular weight decreases and oxidized groups are introduced, making the material more susceptible to microbial degradation dependent on oxygen [363,364]. Such plastics are termed "oxo-degradable", exemplified by Oxo-PP (oxo-degradable polypropylene) [365]. ...
In light of the growing plastic waste problem worldwide, including in agriculture, this study focuses on the usefulness of both conventional, non-degradable plastics and environmentally friendly bioplastics in the agricultural sector. Although conventional plastic products are still essential in modern, even ecological agriculture, the increasing contamination by these materials, especially in a fragmented form, highlights the urgent need to search for alternative, easily biodegradable materials that could replace the non-degradable ones. According to the literature, polymers are widely used in agriculture for the preparation of agrochemicals (mostly fertilizers) with prolonged release. They also play a role as functional polymers against pests, serve as very useful super absorbents of water to improve crop health under drought conditions, and are commonly used as mulching films, membranes, mats, non-woven fabrics, protective nets, seed coatings, agrochemical packaging, or greenhouse coverings. This widespread application leads to the uncontrolled contamination of soil with disintegrated polymeric materials. Therefore, this study highlights the possible applications of bio-based materials as alternatives to conventional polyolefins or other environmentally persistent polymers. Bio-based polymers align with the strategy of innovative agricultural advancements, leading to more productive farming by reducing plastic contamination and adverse ecotoxicological impacts on aquatic and terrestrial organisms. On the other hand, advanced polymer membranes act as catching agents for agrochemicals, protecting against environmental intoxication. The global versatility of polymer applications in agriculture will not permit the elimination of already existing technologies involving polymers in the near future. However, in line with ecological trends in modern agriculture, more “green” polymers should be employed in this sector. Moreover, we highlight that more comprehensive legislative work on these aspects should be undertaken at the European Union level to guarantee environmental and climate protection. From the EU legislation point of view, the implementation of a unified, legally binding system on applications of bio-based, biodegradable, and compostable plastics should be a priority to be addressed. In this respect, the EU already demonstrates an initial action plan. Unfortunately, these are still projected directions for future EU policy, which require in-depth analysis.
