Review of recent advances in the biodegradability of polyhydroxyalkanoate (PHA) bioplastics and their composites

Meereboer, Kjeld W.; Misra, Manjusri; Mohanty, Amar K.

doi:10.1039/d0gc01647k

Cited by 586 publications

(404 citation statements)

References 277 publications

(382 reference statements)

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“…In addition, while PLA is only biodegradable under specific conditions of industrial composting, PHA has the advantage of being industrially and home compostable, anaerobically digestible, and biodegradable in soil and marine environments. In fact, PHA are easily biodegradable by several bacteria that produce extracellular PHA depolymerases (Cooper, 2013;Lambert and Wagner, 2017) and there is enough evidence that PHA are prone to complete and fast biodegradation in natural environments (Meereboer et al, 2020). Under the appropriate sample morphology and environmental conditions (temperature, moisture, microorganisms, nutrients, salinity, and others), PHA can be totally degraded within 28 days in fresh and seawater environments, namely rivers, lakes, or oceans (Meereboer et al, 2020).…”

Section: Polyhydroxyalkanoates (Pha)mentioning

confidence: 99%

Marine Environmental Plastic Pollution: Mitigation by Microorganism Degradation and Recycling Valorization

et al. 2020

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Plastics are very useful materials and present numerous advantages in the daily life of individuals and society. However, plastics are accumulating in the environment and due to their low biodegradability rate, this problem will persist for centuries. Until recently, oceans were treated as places to dispose of litter, thus the persistent substances are causing serious pollution issues. Plastic and microplastic waste has a negative environmental, social, and economic impact, e.g., causing injury/death to marine organisms and entering the food chain, which leads to health problems. The development of solutions and methods to mitigate marine (micro)plastic pollution is in high demand. There is a knowledge gap in this field, reason why research on this thematic is increasing. Recent studies reported the biodegradation of some types of polymers using different bacteria, biofilm forming bacteria, bacterial consortia, and fungi. Biodegradation is influenced by several factors, from the type of microorganism to the type of polymers, their physicochemical properties, and the environment conditions (e.g., temperature, pH, UV radiation). Currently, green environmentally friendly alternatives to plastic made from renewable feedstocks are starting to enter the market. This review covers the period from 1964 to April 2020 and comprehensively gathers investigation on marine plastic and microplastic pollution, negative consequences of plastic use, and bioplastic production. It lists the most useful methods for plastic degradation and recycling valorization, including degradation mediated by microorganisms (biodegradation) and the methods used to detect and analyze the biodegradation.

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Section: Polyhydroxyalkanoates (Pha)mentioning

confidence: 99%

Marine Environmental Plastic Pollution: Mitigation by Microorganism Degradation and Recycling Valorization

et al. 2020

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“…Furthermore, PHA degradation products are easily assimilated into usable products for microbial growth. As a matter of fact, also PLA is a bio-based polymer produced through fermentation of lactic acid, but it is chemically polymerized and, most noteworthy, it is a compostable polymer, making it unsuitable to reduce the plastic waste pollution (Meereboer et al, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

In vivo and Post-synthesis Strategies to Enhance the Properties of PHB-Based Materials: A Review

Turco

Santagata

Corrado

et al. 2021

Front. Bioeng. Biotechnol.

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The transition toward “green” alternatives to petroleum-based plastics is driven by the need for “drop-in” replacement materials able to combine characteristics of existing plastics with biodegradability and renewability features. Promising alternatives are the polyhydroxyalkanoates (PHAs), microbial biodegradable polyesters produced by a wide range of microorganisms as carbon, energy, and redox storage material, displaying properties very close to fossil-fuel-derived polyolefins. Among PHAs, polyhydroxybutyrate (PHB) is by far the most well-studied polymer. PHB is a thermoplastic polyester, with very narrow processability window, due to very low resistance to thermal degradation. Since the melting temperature of PHB is around 170–180°C, the processing temperature should be at least 180–190°C. The thermal degradation of PHB at these temperatures proceeds very quickly, causing a rapid decrease in its molecular weight. Moreover, due to its high crystallinity, PHB is stiff and brittle resulting in very poor mechanical properties with low extension at break, which limits its range of application. A further limit to the effective exploitation of these polymers is related to their production costs, which is mostly affected by the costs of the starting feedstocks. Since the first identification of PHB, researchers have faced these issues, and several strategies to improve the processability and reduce brittleness of this polymer have been developed. These approaches range from the in vivo synthesis of PHA copolymers, to the enhancement of post-synthesis PHB-based material performances, thus the addition of additives and plasticizers, acting on the crystallization process as well as on polymer glass transition temperature. In addition, reactive polymer blending with other bio-based polymers represents a versatile approach to modulate polymer properties while preserving its biodegradability. This review examines the state of the art of PHA processing, shedding light on the green and cost-effective tailored strategies aimed at modulating and optimizing polymer performances. Pioneering examples in this field will be examined, and prospects and challenges for their exploitation will be presented. Furthermore, since the establishment of a PHA-based industry passes through the designing of cost-competitive production processes, this review will inspect reported examples assessing this economic aspect, examining the most recent progresses toward process sustainability.

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“…For this reason, materials such as aliphatic polyesters, e.g., poly(lactide) (PLA), poly(glycolic acid) (PGA), and others, e.g., poly(hydroxyalkanoates) (PHA) are becoming very popular. These polymers can be obtained from natural resources or by bacterial fermentation, thus leading to high efficiency materials from an environmental point of view [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Improvement of Impact Strength of Polylactide Blends with a Thermoplastic Elastomer Compatibilized with Biobased Maleinized Linseed Oil for Applications in Rigid Packaging

et al. 2021

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This research work reports the potential of maleinized linseed oil (MLO) as biobased compatibilizer in polylactide (PLA) and a thermoplastic elastomer, namely, polystyrene-b-(ethylene-ran-butylene)-b-styrene (SEBS) blends (PLA/SEBS), with improved impact strength for the packaging industry. The effects of MLO are compared with a conventional polystyrene-b-poly(ethylene-ran-butylene)-b-polystyrene-graft-maleic anhydride terpolymer (SEBS-g-MA) since it is widely used in these blends. Uncompatibilized and compatibilized PLA/SEBS blends can be manufactured by extrusion and then shaped into standard samples for further characterization by mechanical, thermal, morphological, dynamical-mechanical, wetting and colour standard tests. The obtained results indicate that the uncompatibilized PLA/SEBS blend containing 20 wt.% SEBS gives improved toughness (4.8 kJ/m2) compared to neat PLA (1.3 kJ/m2). Nevertheless, the same blend compatibilized with MLO leads to an increase in impact strength up to 6.1 kJ/m2, thus giving evidence of the potential of MLO to compete with other petroleum-derived compatibilizers to obtain tough PLA formulations. MLO also provides increased ductile properties, since neat PLA is a brittle polymer with an elongation at break of 7.4%, while its blend with 20 wt.% SEBS and MLO as compatibilizer offers an elongation at break of 50.2%, much higher than that provided by typical SEBS-g-MA compatibilizer (10.1%). MLO provides a slight decrease (about 3 °C lower) in the glass transition temperature (Tg) of the PLA-rich phase, thus showing some plasticization effects. Although MLO addition leads to some yellowing due to its intrinsic yellow colour, this can contribute to serving as a UV light barrier with interesting applications in the packaging industry. Therefore, MLO represents a cost-effective and sustainable solution to the use of conventional petroleum-derived compatibilizers.

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Review of recent advances in the biodegradability of polyhydroxyalkanoate (PHA) bioplastics and their composites

Abstract: Poly(hydroxyalkanoate)s (PHAs) represent a promising solution to allay climate change and plastic waste pollution. Being both completely bio-based and biodegradable, PHAs can approach a carbon neutral platform whereas petroleum-based plastics cannot.

Cited by 586 publications

References 277 publications

Marine Environmental Plastic Pollution: Mitigation by Microorganism Degradation and Recycling Valorization

Marine Environmental Plastic Pollution: Mitigation by Microorganism Degradation and Recycling Valorization

In vivo and Post-synthesis Strategies to Enhance the Properties of PHB-Based Materials: A Review

Improvement of Impact Strength of Polylactide Blends with a Thermoplastic Elastomer Compatibilized with Biobased Maleinized Linseed Oil for Applications in Rigid Packaging

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