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García-Depraect O, Martínez-Mendoza LJ, Aragão Börner R, Zimmer J, Muñoz R. Biomethanization of rigid packaging made entirely of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate): Mono- and co-digestion tests and microbial insights. BIORESOURCE TECHNOLOGY 2024; 408:131180. [PMID: 39098356 DOI: 10.1016/j.biortech.2024.131180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 07/25/2024] [Accepted: 07/29/2024] [Indexed: 08/06/2024]
Abstract
This study evaluates the anaerobic mesophilic mono- and co-digestion of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) plastic bottles as a proxy for rigid packaging materials. Initial tests showed a 97.3 ± 0.2 % reduction in weight and an observable alteration in the surface (thinning, color fading and pitting) of the PHBH bottles after eight weeks. Subsequent tests showed that PHBH squares (3 × 3 cm) produced 400 NmL-CH4/g-VSfed, at a slower rate compared to powdered PHBH but with similar methane yield. Co-digestion experiments with food waste, swine manure, or sewage sludge showed successful digestion of PHBH alongside organic waste (even at a high bioplastic loading of 20 % volatile solids basis), with methane production comparable to or slightly higher than that observed in mono-digestion. Molecular analyses suggested that the type of co-substrate influenced microbial activity and that methane production was mainly driven by hydrogenotrophic methanogenesis. These results suggest the potential for integrating rigid PHBH packaging into anaerobic digesters.
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Affiliation(s)
- Octavio García-Depraect
- Institute of Sustainable Processes, Dr. Mergelina s/n, 47011 Valladolid, Spain; Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011 Valladolid, Spain
| | - Leonardo J Martínez-Mendoza
- Institute of Sustainable Processes, Dr. Mergelina s/n, 47011 Valladolid, Spain; Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011 Valladolid, Spain
| | - Rosa Aragão Börner
- Nestlé Research, Société des Produits Nestlé S.A., Route du Jorat 57, 1000 Lausanne, Switzerland
| | - Johannes Zimmer
- Nestlé Research, Société des Produits Nestlé S.A., Route du Jorat 57, 1000 Lausanne, Switzerland
| | - Raúl Muñoz
- Institute of Sustainable Processes, Dr. Mergelina s/n, 47011 Valladolid, Spain; Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011 Valladolid, Spain.
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Guicherd M, Ben Khaled M, Guéroult M, Nomme J, Dalibey M, Grimaud F, Alvarez P, Kamionka E, Gavalda S, Noël M, Vuillemin M, Amillastre E, Labourdette D, Cioci G, Tournier V, Kitpreechavanich V, Dubois P, André I, Duquesne S, Marty A. An engineered enzyme embedded into PLA to make self-biodegradable plastic. Nature 2024; 631:884-890. [PMID: 39020178 DOI: 10.1038/s41586-024-07709-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 06/12/2024] [Indexed: 07/19/2024]
Abstract
Plastic production reached 400 million tons in 2022 (ref. 1), with packaging and single-use plastics accounting for a substantial amount of this2. The resulting waste ends up in landfills, incineration or the environment, contributing to environmental pollution3. Shifting to biodegradable and compostable plastics is increasingly being considered as an efficient waste-management alternative4. Although polylactide (PLA) is the most widely used biosourced polymer5, its biodegradation rate under home-compost and soil conditions remains low6-8. Here we present a PLA-based plastic in which an optimized enzyme is embedded to ensure rapid biodegradation and compostability at room temperature, using a scalable industrial process. First, an 80-fold activity enhancement was achieved through structure-based rational engineering of a new hyperthermostable PLA hydrolase. Second, the enzyme was uniformly dispersed within the PLA matrix by means of a masterbatch-based melt extrusion process. The liquid enzyme formulation was incorporated in polycaprolactone, a low-melting-temperature polymer, through melt extrusion at 70 °C, forming an 'enzymated' polycaprolactone masterbatch. Masterbatch pellets were integrated into PLA by melt extrusion at 160 °C, producing an enzymated PLA film (0.02% w/w enzyme) that fully disintegrated under home-compost conditions within 20-24 weeks, meeting home-composting standards. The mechanical and degradation properties of the enzymated film were compatible with industrial packaging applications, and they remained intact during long-term storage. This innovative material not only opens new avenues for composters and biomethane production but also provides a feasible industrial solution for PLA degradation.
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Affiliation(s)
- M Guicherd
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
- Carbios, Clermont-Ferrand, France
| | - M Ben Khaled
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - M Guéroult
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
- Carbios, Clermont-Ferrand, France
| | - J Nomme
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | | | | | - P Alvarez
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - E Kamionka
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - S Gavalda
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
- Carbios, Clermont-Ferrand, France
| | - M Noël
- Carbiolice, Clermont-Ferrand, France
| | - M Vuillemin
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - E Amillastre
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - D Labourdette
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - G Cioci
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | | | - V Kitpreechavanich
- Department of Microbiology, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - P Dubois
- Center of Innovation and Research in Materials & Polymers, University of Mons, Mons, Belgium
| | - I André
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France.
| | - S Duquesne
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - A Marty
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France.
- Carbios, Clermont-Ferrand, France.
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Vasmara C, Cazaudehore G, Ceotto E, Marchetti R, Sambusiti C, Monlau F. Alkali, thermal, or thermo-alkali pre-treatment to improve the anaerobic digestion of poly(lactic acid)? WATER RESEARCH 2024; 258:121744. [PMID: 38754301 DOI: 10.1016/j.watres.2024.121744] [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: 11/17/2023] [Revised: 03/26/2024] [Accepted: 05/05/2024] [Indexed: 05/18/2024]
Abstract
Replacing petroleum-based plastics with biodegradable polymers is a major challenge for modern society especially for food packaging applications. To date, poly(lactic acid) represents 25 % of the total biodegradable plastics and it is estimated that, in the future, it could become the main contributor to the biodegradable plastics industry. Anaerobic digestion is an interesting way for the poly(lactic acid) end of life, even if its biodegradability is limited in mesophilic conditions. The aims of this study were to identify the best pre-treatment for maximizing the methane yield, minimizing the anaerobic digestion duration and limiting residual plastic fragments in the digestate. A systematic comparison was carried out between thermal, chemical, and thermo-chemical pre-treatment. Pre-treatment with 4 M KOH for 48 h at 35°C was effective in improving the mesophilic anaerobic digestion of the poly(lactic acid). Such pre-treatment allows obtaining 90 % of the theoretical methane potential, in 24 - 30 days. Importantly, such pre-treatment completely solubilized the poly(lactic acid), leaving no solid residues in the digestate. In addition, using KOH permits to avoid the sodication of the soil due to the digestate application as fertilizer.
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Affiliation(s)
- C Vasmara
- CREA, Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture, Via Salaria 31, Monterotondo, Rome 00015, Italy.
| | - G Cazaudehore
- APESA, Pôle Valorisation, Montardon 64121, France; Universite de Pau et des Pays de l 'Adour / E2S UPPA / CNRS, IPREM UMR5254, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, Chimie et Microbiologie de l'Environnement, Pau 64000, France
| | - E Ceotto
- CREA, Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture, Via Beccastecca 345, S. Cesario sul Panaro, Modena 41018, Italy
| | - R Marchetti
- CREA, Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture, Via Beccastecca 345, S. Cesario sul Panaro, Modena 41018, Italy
| | - C Sambusiti
- Total Energies OneTech R&D, CSTJF - Avenue Larribau, Pau 64018, France
| | - F Monlau
- APESA, Pôle Valorisation, Montardon 64121, France; Total Energies OneTech R&D, PERL - Pôle D'Etudes et de Recherche de Lacq, Pôle Economique 2, BP 47 - RD 817, Lacq 64170, France
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Yasin NM, Pancho F, Yasin M, Van Impe JFM, Akkermans S. Novel methods to monitor the biodegradation of polylactic acid (PLA) by Amycolatopsis orientalis and Amycolatopsis thailandensis. Front Bioeng Biotechnol 2024; 12:1355050. [PMID: 38655392 PMCID: PMC11035760 DOI: 10.3389/fbioe.2024.1355050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
Plastics are essential in modern life, but their conventional production is problematic due to environmental pollution and waste management issues. Polylactic acid (PLA) is a widely used bioplastic that is bio-based and biodegradable, making it a key player in the bioeconomy. PLA has been proven to be degradable in various settings, including aqueous, soil, and compost environments. However, monitoring and optimizing PLA biodegradation remains challenging. This study proposes methods to improve the quantification of PLA biodegradation by Amycolatopsis spp. Ultrasound treatments (10 s) significantly improved the enumeration of viable Amycolatopsis cells by breaking the pellets into quantifiable individual cells. A separation technique combining ultrasound (120 s) and 40 μm cell strainers effectively isolated PLA particles from biomass to quantify PLA weight loss. This enabled the monitoring of PLA biofragmentation. Finally, CO2 production was measured according to ISO 14852 to quantify mineralization. Integrating these methods provides an improved quantification for PLA biodegradation along its different stages. In a case study, this led to the construction of a carbon balance where 85.1% of initial carbon content was successfully tracked. The developed techniques for monitoring of PLA biodegradation are essential to design future waste management strategies for biodegradable plastics.
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Affiliation(s)
- Najwa Mat Yasin
- BioTeC+ - Chemical and Biochemical Process Technology and Control, KU Leuven, Ghent, Belgium
- Faculty of Ocean Engineering and Informatics, Universiti Malaysia Terengganu (UMT), Kuala Nerus, Terengganu, Malaysia
| | - Farlash Pancho
- BioTeC+ - Chemical and Biochemical Process Technology and Control, KU Leuven, Ghent, Belgium
| | - Md Yasin
- BioTeC+ - Chemical and Biochemical Process Technology and Control, KU Leuven, Ghent, Belgium
| | - Jan F. M. Van Impe
- BioTeC+ - Chemical and Biochemical Process Technology and Control, KU Leuven, Ghent, Belgium
| | - Simen Akkermans
- BioTeC+ - Chemical and Biochemical Process Technology and Control, KU Leuven, Ghent, Belgium
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Ashraf Joolaei A, Makian M, Prakash O, Im S, Kang S, Kim DH. Effects of particle size on the pretreatment efficiency and subsequent biogas potential of polylactic acid. BIORESOURCE TECHNOLOGY 2024; 394:130306. [PMID: 38199437 DOI: 10.1016/j.biortech.2024.130306] [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: 11/13/2023] [Revised: 01/05/2024] [Accepted: 01/06/2024] [Indexed: 01/12/2024]
Abstract
The fragmentation of bioplastics (BPs) before pretreatment and anaerobic digestion is conducted for higher efficiency; however, based on the literature, the size reduction varies widely. In this study, initially, various combinations of thermal-alkaline pretreatments were applied at different strengths to the polylactic acid (PLA) in three groups (<0.5, 0.5 < size < 1.0, and 1.0 < size < 2.0 mm). After pretreatment, the solubilization of PLA was increased to 11.5-40.0 % using alkaline dosage and temperature ranging from 50 to 200 g OH-/kg BP, 60-100 °C, respectively, in a 1-10 h timeframe. The results were statistically proved using a 3D response surface graph, where the pretreatment was more effective for smaller particle sizes. The reduction in particle size also increased the CH4 production, which was more pronounced at the strong pretreatment (24 % increment vs. 10-15 %). Computed results indicated 44-86 % conversion of pretreated PLA particles to CH4, supported by Fourier transform infrared spectroscopy analysis, especially focusing on the intensity of -OH bands.
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Affiliation(s)
- Ali Ashraf Joolaei
- Department of Smart-city Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea
| | - Masoud Makian
- Department of Smart-city Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea
| | - Om Prakash
- Department of Smart-city Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea
| | - Seongwon Im
- Department of Environmental Research, Korea Institute of Civil Engineering and Building Technology, Goyang-si, Gyeonggi-do, Republic of Korea
| | - Sungwon Kang
- Department of Environmental Research, Korea Institute of Civil Engineering and Building Technology, Goyang-si, Gyeonggi-do, Republic of Korea
| | - Dong-Hoon Kim
- Department of Smart-city Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea.
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