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Lavagnolo MC, Poli V, Zampini AM, Grossule V. Biodegradability of bioplastics in different aquatic environments: A systematic review. J Environ Sci (China) 2024; 142:169-181. [PMID: 38527882 DOI: 10.1016/j.jes.2023.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 06/08/2023] [Accepted: 06/08/2023] [Indexed: 03/27/2024]
Abstract
Bioplastics were first introduced as environmentally friendly materials, with properties similar to those of conventional plastics. A bioplastic is defined as biodegradable if it can be decomposed into carbon dioxide under aerobic degradation, or methane and CO2 under anaerobic conditions, inorganic compounds, and new cellular biomass, by the action of naturally occurring microorganisms. This definition however does not provide any information on the environmental conditions, timescale and extent at which decomposition processes should occur. With regard to the aquatic environment, recognized standards have been established to assess the ability of plastics to undergo biodegradation; however, these standards fail to provide clear targets to be met to allow labelling of a bioplastic as biodegradable. Moreover, these standards grant the user an extensive leeway in the choice of process parameters. For these reasons, the comparison of results deriving from different studies is challenging. The authors analysed and discussed the degree of biodegradability of a series of biodegradable bioplastics in aquatic environments (both fresh and salt water) using the results obtained in the laboratory and from on-site testing in the context of different research studies. Biochemical Oxygen Demand (BOD), CO2 evolution, surface erosion and weight loss were the main parameters used by researchers to describe the percentage of biodegradation. The results showed a large variability both in weight loss and BOD, even when evaluating the same type of bioplastics. This confirms the need for a reference range of values to be established with regard to parameters applied in defining the biodegradability of bioplastics.
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Affiliation(s)
- Maria Cristina Lavagnolo
- Department of Civil, Environmental and Architectural Engineering - Laboratory of Environmental Engineering, University of Padova, Lungargine Rovetta 8, Padova 35100, Italy.
| | - Valentina Poli
- Department of Civil, Environmental and Architectural Engineering - Laboratory of Environmental Engineering, University of Padova, Lungargine Rovetta 8, Padova 35100, Italy
| | - Anna Maria Zampini
- Department of Civil, Environmental and Architectural Engineering - Laboratory of Environmental Engineering, University of Padova, Lungargine Rovetta 8, Padova 35100, Italy
| | - Valentina Grossule
- Department of Civil, Environmental and Architectural Engineering - Laboratory of Environmental Engineering, University of Padova, Lungargine Rovetta 8, Padova 35100, Italy
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Piyathilake U, Lin C, Bolan N, Bundschuh J, Rinklebe J, Herath I. Exploring the hidden environmental pollution of microplastics derived from bioplastics: A review. CHEMOSPHERE 2024; 355:141773. [PMID: 38548076 DOI: 10.1016/j.chemosphere.2024.141773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/16/2024] [Accepted: 03/21/2024] [Indexed: 04/18/2024]
Abstract
Bioplastics might be an ecofriendly alternative to traditional plastics. However, recent studies have emphasized that even bioplastics can end up becoming micro- and nano-plastics due to their degradation under ambient environmental conditions. Hence, there is an urgent need to assess the hidden environmental pollution caused by bioplastics. However, little is known about the evolutionary trends of bibliographic data, degradation pathways, formation, and toxicity of micro- and nano-scaled bioplastics originating from biodegradable polymers such as polylactic acid, polyhydroxyalkanoates, and starch-based plastics. Therefore, the prime objective of the current review was to investigate evolutionary trends and the latest advancements in the field of micro-bioplastic pollution. Additionally, it aims to confront the limitations of existing research on microplastic pollution derived from the degradation of bioplastic wastes, and to understand what is needed in future research. The literature survey revealed that research focusing on micro- and nano-bioplastics has begun since 2012. This review identifies novel insights into microbioplastics formation through diverse degradation pathways, including photo-oxidation, ozone-induced degradation, mechanochemical degradation, biodegradation, thermal, and catalytic degradation. Critical research gaps are identified, including defining optimal environmental conditions for complete degradation of diverse bioplastics, exploring micro- and nano-bioplastics formation in natural environments, investigating the global occurrence and distribution of these particles in diverse ecosystems, assessing toxic substances released during bioplastics degradation, and bridging the disparity between laboratory studies and real-world applications. By identifying new trends and knowledge gaps, this study lays the groundwork for future investigations and sustainable solutions in the realm of sustainable management of bioplastic wastes.
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Affiliation(s)
- Udara Piyathilake
- Environmental Science Division, National Institute of Fundamental Studies (NIFS), Kandy, 2000, Sri Lanka
| | - Chuxia Lin
- Centre for Regional and Rural Futures, Faculty of Science, Engineering and Built Environment, Deakin University, Burwood, VIC, 3125, Australia
| | - Nanthi Bolan
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, Western Australia, 6009, Australia; The UWA Institute of Agriculture, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Jochen Bundschuh
- School of Engineering, Faculty of Health, Engineering and Sciences, The University of Southern Queensland, West Street, 4350, QLD, Australia
| | - Jörg Rinklebe
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Laboratory of Soil- and Groundwater-Management, Pauluskirchstraße 7, 42285, Wuppertal, Germany
| | - Indika Herath
- Centre for Regional and Rural Futures, Faculty of Science, Engineering and Built Environment, Deakin University, Waurn Ponds, VIC, 3216, Australia.
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Omura T, Tsujimoto S, Kimura S, Maehara A, Kabe T, Iwata T. Marine biodegradation of poly[( R)-3-hydroxybutyrate- co-4-hydroxybutyrate] elastic fibers in seawater: dependence of decomposition rate on highly ordered structure. Front Bioeng Biotechnol 2023; 11:1303830. [PMID: 38188489 PMCID: PMC10766686 DOI: 10.3389/fbioe.2023.1303830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 12/07/2023] [Indexed: 01/09/2024] Open
Abstract
Here, we report the marine degradability of polymers with highly ordered structures in natural environmental water using microbial degradation and biochemical oxygen demand (BOD) tests. Three types of elastic fibers (non-porous as-spun, non-porous drawn, and porous drawn) with different highly ordered structures were prepared using poly[(R)-3-hydroxybutyrate-co-16 mol%-4-hydroxybutyrate] [P(3HB-co-16 mol%-4HB)], a well-known polyhydroxyalkanoate. Scanning electron microscopy (SEM) images indicated that microorganisms attached to the fiber surface within several days of testing and degraded the fiber without causing physical disintegration. The results of BOD tests revealed that more than 80% of P(3HB-co-16 mol%-4HB) was degraded by microorganisms in the ocean. The plastisphere was composed of a wide variety of microorganisms, and the microorganisms accumulated on the fiber surfaces differed from those in the biofilms. The microbial degradation rate increased as the degree of molecular orientation and porosity of the fiber increased: as-spun fiber < non-porous drawn fiber < porous drawn fiber. The drawing process induced significant changes in the highly ordered structure of the fiber, such as molecular orientation and porosity, without affecting the crystallinity. The results of SEM observations and X-ray measurements indicated that drawing the fibers oriented the amorphous chains, which promoted enzymatic degradation by microorganisms.
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Affiliation(s)
- Taku Omura
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Sakura Tsujimoto
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan
- Graduate School of Industrial Technology, Nihon University, Narashino, Japan
| | - Satoshi Kimura
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Akira Maehara
- Niigata Research Laboratory, Mitsubishi Gas Chemical Co., Inc., Niigata, Japan
| | - Taizo Kabe
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Tadahisa Iwata
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan
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Huang Q, Kimura S, Iwata T. Thermal Embedding of Humicola insolens Cutinase: A Strategy for Improving Polyester Biodegradation in Seawater. Biomacromolecules 2023; 24:5836-5846. [PMID: 37940601 DOI: 10.1021/acs.biomac.3c00835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
By thermal embedding of the commercially available enzyme Humicola insolens cutinase (HiC), this study successfully enhanced the biodegradability of various polyesters (PBS, PBSA, PCL, PBAT) in seawater, which otherwise show limited environmental degradability. Melt extrusion above the melting temperature was used for embedding HiC in the polyesters. The overall physical properties of the HiC-embedded films remained almost unchanged compared to those of the neat films. In the buffer, embedding HiC allowed rapid polymer degradation into water-soluble hydrolysis products. Biochemical oxygen demand tests showed that the HiC-embedded polyester films exhibited similar or much higher biodegradability than the biodegradable cellulose standard in natural seawater. Thermal embedding of HiC aims to accelerate the biodegradation of plastics that are already biodegradable but have limited environmental biodegradability, potentially reducing their contribution to environmental problems such as marine microplastics.
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Affiliation(s)
- QiuYuan Huang
- Science of Polymeric Materials, Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Satoshi Kimura
- Science of Polymeric Materials, Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Tadahisa Iwata
- Science of Polymeric Materials, Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Degli-Innocenti F, Breton T, Chinaglia S, Esposito E, Pecchiari M, Pennacchio A, Pischedda A, Tosin M. Microorganisms that produce enzymes active on biodegradable polyesters are ubiquitous. Biodegradation 2023; 34:489-518. [PMID: 37354274 DOI: 10.1007/s10532-023-10031-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/30/2023] [Indexed: 06/26/2023]
Abstract
Biodegradability standards measure ultimate biodegradation of polymers by exposing the material under test to a natural microbial inoculum. Available tests developed by the International Organization for Standardization (ISO) use inoculums sampled from different environments e.g. soil, marine sediments, seawater. Understanding whether each inoculum is to be considered as microbially unique or not can be relevant for the interpretation of tests results. In this review, we address this question by consideration of the following: (i) the chemical nature of biodegradable plastics (virtually all biodegradable plastics are polyesters) (ii) the diffusion of ester bonds in nature both in simple molecules and in polymers (ubiquitous); (iii) the diffusion of decomposers capable of producing enzymes, called esterases, which accelerate the hydrolysis of esters, including polyesters (ubiquitous); (iv) the evidence showing that synthetic polyesters can be depolymerized by esterases (large and growing); (v) the evidence showing that these esterases are ubiquitous (growing and confirmed by bioinformatics studies). By combining the relevant available facts it can be concluded that if a certain polyester shows ultimate biodegradation when exposed to a natural inoculum, it can be considered biodegradable and need not be retested using other inoculums. Obviously, if the polymer does not show ultimate biodegradation it must be considered recalcitrant, until proven otherwise.
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Affiliation(s)
| | - Tony Breton
- Novamont S.p.A., via Fauser 8, 28100, Novara, Italy
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Albright VC, Chai Y. Knowledge Gaps in Polymer Biodegradation Research. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:11476-11488. [PMID: 34374525 DOI: 10.1021/acs.est.1c00994] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The environmental fate of polymers has attracted growing attention in the academic, industrial, and regulatory communities as well as in the general public as global production and use of polymers continue to increase. Biodegradable polymers especially have drawn significant interest. Polymer biodegradation literature published over the past decade was reviewed to compare test methods commonly used for evaluating polymer biodegradation, and to identify key areas for improvement. This paper examines key aspects of study design for polymer biodegradation such as physical form of the test material, use of appropriate reference materials, selection of test systems, and advantages and limitations of various analytical methods for determining biodegradation. Those aspects of study design are critical for determining the outcome of polymer biodegradation studies. This paper identifies several knowledge gaps for assessing polymer biodegradation and provides four key recommendations. (1) develop standardized guidelines for each specific environmental matrix (compost, activated sludge, marine environments, etc.) that can used for all polymer types, (2) develop accelerated biodegradation test methods and predictive methods for polymers, (3) develop an integrated analytical approach using multiple simple, and effective analytical methods, and (4) develop new frameworks for assessing the overall persistence of polymers and are accepted by the greater scientific community.
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Affiliation(s)
- Vurtice C Albright
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, 1803 Building, Midland, Michigan 48674, United States
| | - Yunzhou Chai
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, 1803 Building, Midland, Michigan 48674, United States
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Huang Q, Kimura S, Iwata T. Development of self-degradable aliphatic polyesters by embedding lipases via melt extrusion. Polym Degrad Stab 2021. [DOI: 10.1016/j.polymdegradstab.2021.109647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Mechanical properties and biodegradation of biocomposites based on poly (hydroxybutyrate-co-valerate) and alfa fibers. JOURNAL OF POLYMER RESEARCH 2020. [DOI: 10.1007/s10965-020-02284-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Suzuki M, Tachibana Y, Kasuya KI. Biodegradability of poly(3-hydroxyalkanoate) and poly(ε-caprolactone) via biological carbon cycles in marine environments. Polym J 2020. [DOI: 10.1038/s41428-020-00396-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
AbstractApproximately 4.8–12.7 million tons of plastic waste has been estimated to be discharged into marine environments annually by wind and river currents. The Ellen MacArthur Foundation warns that the total weight of plastic waste in the oceans will exceed the total weight of fish in 2050 if the environmental runoff of plastic continues at the current rate. Hence, biodegradable plastics are attracting attention as a solution to the problems caused by plastic waste. Among biodegradable plastics, polyhydroxyalkanoates (PHAs) and poly(ε-caprolactone) (PCL) are particularly noteworthy because of their excellent marine biodegradability. In this review, the biosynthesis of PHA and cutin, a natural analog of PCL, and the biodegradation of PHA and PCL in carbon cycles in marine ecosystems are discussed. PHA is biosynthesized and biodegraded by various marine microbes in a wide range of marine environments, including coastal, shallow-water, and deep-sea environments. Marine cutin is biosynthesized by marine plants or obtained from terrestrial environments, and PCL and cutin are biodegraded by cutin hydrolytic enzyme-producing microbes in broad marine environments. Thus, biological carbon cycles for PHA and PCL exist in the marine environment, which would allow materials made of PHA and PCL to be quickly mineralized in marine environments.
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