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Černoša A, Cortizas AM, Traoré M, Podlogar M, Danevčič T, Gunde-Cimerman N, Gostinčar C. A screening method for plastic-degrading fungi. Heliyon 2024; 10:e31130. [PMID: 38803974 PMCID: PMC11128935 DOI: 10.1016/j.heliyon.2024.e31130] [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: 01/22/2024] [Revised: 05/06/2024] [Accepted: 05/10/2024] [Indexed: 05/29/2024] Open
Abstract
The growing amount of plastic waste requires new ways of disposal or recycling. Research into the biodegradation of recalcitrant plastic polymers is gathering pace. Despite some progress, these efforts have not yet led to technologically and economically viable applications. In this study, we show that respirometric screening of environmental fungal isolates in combination with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy can be used to identify new strains with the potential for the degradation of plastic polymers. We screened 146 fungal strains, 71 isolated from car repair shops, an environment rich in long-chain hydrocarbons, and 75 isolated from hypersaline water capable of growing at high concentrations of NaCl. When grown in a minimal medium with no carbon source, some strains produced significantly more CO2 when a pure plastic polymer was added to the medium, some only at high salinity. A selection of these strains was shown by FTIR and Raman spectroscopy to alter the properties of plastic polymers: Cladosporium sp. EXF-13502 on polyamide, Rhodotorula dairenensis EXF-13500 on polypropylene, Rhodotorula sp. EXF-10630 on low-density polyethylene and Wickerhamomyces anomalus EXF-6848 on polyethylene terephthalate. Respirometry in combination with specific spectroscopic methods is an efficient method for screening microorganisms capable of at least partial plastic degradation and can be used to expand the repertoire of potential plastic degraders. This is of particular importance as our results also show that individual strains are only active against certain polymers and under certain conditions. Therefore, efficient biodegradation of plastics is likely to depend on a collection of specialized microorganisms rather than a single universal plastic degrader.
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Affiliation(s)
- Anja Černoša
- University of Ljubljana, Biotechnical Faculty, Department of Biology, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
- InnoRenew CoE, Livade 6a, 6310 Izola, Slovenia
| | - Antonio Martínez Cortizas
- CRETUS, EcoPast research group (GI-1553), Departamento de Edafoloxía e Química Agrícola, Faculty of Biology, Universidade de Santiago de Compostela, Campus Vida, 15782, Spain
- Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
| | - Mohamed Traoré
- CRETUS, EcoPast research group (GI-1553), Departamento de Edafoloxía e Química Agrícola, Faculty of Biology, Universidade de Santiago de Compostela, Campus Vida, 15782, Spain
| | - Matejka Podlogar
- Department for Nanostructured Materials, Jožef Stefan Institute, Jamova cesta 39, Ljubljana, Slovenia
| | - Tjaša Danevčič
- University of Ljubljana, Biotechnical Faculty, Department of Microbiology, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
| | - Nina Gunde-Cimerman
- University of Ljubljana, Biotechnical Faculty, Department of Biology, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
| | - Cene Gostinčar
- University of Ljubljana, Biotechnical Faculty, Department of Biology, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
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2
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Parida D, Katare K, Ganguly A, Chakraborty D, Konar O, Nogueira R, Bala K. Molecular docking and metagenomics assisted mitigation of microplastic pollution. CHEMOSPHERE 2024; 351:141271. [PMID: 38262490 DOI: 10.1016/j.chemosphere.2024.141271] [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: 09/29/2023] [Revised: 01/18/2024] [Accepted: 01/19/2024] [Indexed: 01/25/2024]
Abstract
Microplastics, tiny, flimsy, and direct progenitors of principal and subsidiary plastics, cause environmental degradation in aquatic and terrestrial entities. Contamination concerns include irrevocable impacts, potential cytotoxicity, and negative health effects on mortals. The detection, recovery, and degradation strategies of these pollutants in various biota and ecosystems, as well as their impact on plants, animals, and humans, have been a topic of significant interest. But the natural environment is infested with several types of plastics, all having different chemical makeup, structure, shape, and origin. Plastic trash acts as a substrate for microbial growth, creating biofilms on the plastisphere surface. This colonizing microbial diversity can be glimpsed with meta-genomics, a culture-independent approach. Owing to its comprehensive description of microbial communities, genealogical evidence on unconventional biocatalysts or enzymes, genomic correlations, evolutionary profile, and function, it is being touted as one of the promising tools in identifying novel enzymes for the degradation of polymers. Additionally, computational tools such as molecular docking can predict the binding of these novel enzymes to the polymer substrate, which can be validated through in vitro conditions for its environmentally feasible applications. This review mainly deals with the exploration of metagenomics along with computational tools to provide a clearer perspective into the microbial potential in the biodegradation of microplastics. The computational tools due to their polymathic nature will be quintessential in identifying the enzyme structure, binding affinities of the prospective enzymes to the substrates, and foretelling of degradation pathways involved which can be quite instrumental in the furtherance of the plastic degradation studies.
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Affiliation(s)
- Dinesh Parida
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology, Indore, 453552, India.
| | - Konica Katare
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology, Indore, 453552, India.
| | - Atmaadeep Ganguly
- Department of Microbiology, Ramakrishna Mission Vivekananda Centenary College, West Bengal State University, Kolkata, 700118, India.
| | - Disha Chakraborty
- Department of Botany, Shri Shikshayatan College, University of Calcutta, Lord Sinha Road, Kolkata, 700071, India.
| | - Oisi Konar
- Department of Botany, Shri Shikshayatan College, University of Calcutta, Lord Sinha Road, Kolkata, 700071, India.
| | - Regina Nogueira
- Institute of Sanitary Engineering and Waste Management, Leibniz Universität, Hannover, Germany.
| | - Kiran Bala
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology, Indore, 453552, India.
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3
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Jiménez DJ, Sanchez A, Dini-Andreote F. Engineering microbiomes to transform plastics. Trends Biotechnol 2024; 42:265-268. [PMID: 37845169 DOI: 10.1016/j.tibtech.2023.09.011] [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: 08/04/2023] [Revised: 09/24/2023] [Accepted: 09/25/2023] [Indexed: 10/18/2023]
Abstract
The design and study of active microbial consortia able to degrade plastics represent an exciting area of research toward the development of bio-based alternatives to efficiently transform plastic waste. This forum article discusses concepts and mechanisms to inform emerging strategies for engineering microbiomes to transform plastics under controlled settings.
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Affiliation(s)
- Diego Javier Jiménez
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
| | - Alvaro Sanchez
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología - CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Francisco Dini-Andreote
- Department of Plant Science and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA; The One Health Microbiome Center, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
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4
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Zhou X, Zhou X, Xu Z, Zhang M, Zhu H. Characterization and engineering of plastic-degrading polyesterases jmPE13 and jmPE14 from Pseudomonas bacterium. Front Bioeng Biotechnol 2024; 12:1349010. [PMID: 38425995 PMCID: PMC10904013 DOI: 10.3389/fbioe.2024.1349010] [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: 12/04/2023] [Accepted: 01/31/2024] [Indexed: 03/02/2024] Open
Abstract
Polyester plastics are widely used in daily life, but also cause a large amount of waste. Degradation by microbial enzymes is the most promising way for the biobased upcycling of the wastes. However, there is still a shortage of high-performance enzymes, and more efficient polyester hydrolases need to be developed. Here we identified two polyester hydrolases, jmPE13 and jmPE14, from a previously isolated strain Pseudomonas sp. JM16B3. The proteins were recombinantly expressed and purified in E. coli, and their enzymatic properties were characterized. JmPE13 and jmPE14 showed hydrolytic activity towards polyethylene terephthalate (PET) and Poly (butylene adipate-co-terephthalate) (PBAT) at medium temperatures. The enzyme activity and stability of jmPE13 were further improved to 3- and 1.5-fold, respectively, by rational design. The results of our research can be helpful for further engineering of more efficient polyester plastic hydrolases and their industrial applications.
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Affiliation(s)
| | | | | | | | - Honghui Zhu
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Key Laboratory of Agricultural Microbiome (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
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5
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Jiao H, Ali SS, Alsharbaty MHM, Elsamahy T, Abdelkarim E, Schagerl M, Al-Tohamy R, Sun J. A critical review on plastic waste life cycle assessment and management: Challenges, research gaps, and future perspectives. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 271:115942. [PMID: 38218104 DOI: 10.1016/j.ecoenv.2024.115942] [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: 09/08/2023] [Revised: 12/12/2023] [Accepted: 01/03/2024] [Indexed: 01/15/2024]
Abstract
The global production and consumption of plastics, as well as their deposition in the environment, are experiencing exponential growth. In addition, mismanaged plastic waste (PW) losses into drainage channels are a growing source of microplastic (MP) pollution concern. However, the complete understanding of their environmental implications throughout their life cycle is yet to be fully understood. Determining the potential extent to which MPs contribute to overall ecotoxicity is possible through the monitoring of PW release and MP removal during remediation. Life cycle assessments (LCAs) have been extensively utilized in many comparative analyses, such as comparing petroleum-based plastics with biomass and single-use plastics with multi-use alternatives. These assessments typically yield unexpected or paradoxical results. Nevertheless, there is still a paucity of reliable data and tools for conducting LCAs on plastics. On the other hand, the release and impact of MP have so far not been considered in LCA studies. This is due to the absence of inventory-related data regarding MP releases and the characterization factors necessary to quantify the effects of MP. Therefore, this review paper conducts a comprehensive literature review in order to assess the current state of knowledge and data regarding the environmental impacts that occur throughout the life cycle of plastics, along with strategies for plastic management through LCA.
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Affiliation(s)
- Haixin Jiao
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Sameh S Ali
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; Botany Department, Faculty of Science, Tanta University, Tanta 31527, Egypt.
| | - Mohammed Husssein M Alsharbaty
- Department of Prosthodontics, College of Dentistry, University of Baghdad, Baghdad, Iraq; Branch of Prosthodontics, College of Dentistry, University of Al-Ameed, Karbala, Iraq.
| | - Tamer Elsamahy
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Esraa Abdelkarim
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Michael Schagerl
- Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, Vienna A-1030, Austria.
| | - Rania Al-Tohamy
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Jianzhong Sun
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
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6
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Díaz-García L, Chuvochina M, Feuerriegel G, Bunk B, Spröer C, Streit WR, Rodriguez-R LM, Overmann J, Jiménez DJ. Andean soil-derived lignocellulolytic bacterial consortium as a source of novel taxa and putative plastic-active enzymes. Syst Appl Microbiol 2024; 47:126485. [PMID: 38211536 DOI: 10.1016/j.syapm.2023.126485] [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: 07/18/2023] [Revised: 10/19/2023] [Accepted: 12/01/2023] [Indexed: 01/13/2024]
Abstract
An easy and straightforward way to engineer microbial environmental communities is by setting up liquid enrichment cultures containing a specific substrate as the sole source of carbon. Here, we analyzed twenty single-contig high-quality metagenome-assembled genomes (MAGs) retrieved from a microbial consortium (T6) that was selected by the dilution-to-stimulation approach using Andean soil as inoculum and lignocellulose as a selection pressure. Based on genomic metrics (e.g., average nucleotide and amino acid identities) and phylogenomic analyses, 15 out of 20 MAGs were found to represent novel bacterial species, with one of those (MAG_26) belonging to a novel genus closely related to Caenibius spp. (Sphingomonadaceae). Following the rules and requirements of the SeqCode, we propose the name Andeanibacterium colombiense gen. nov., sp. nov. for this taxon. A subsequent functional annotation of all MAGs revealed that MAG_7 (Pseudobacter hemicellulosilyticus sp. nov.) contains 20, 19 and 16 predicted genes from carbohydrate-active enzymes families GH43, GH2 and GH92, respectively. Its lignocellulolytic gene profile resembles that of MAG_2 (the most abundant member) and MAG_3858, both of which belong to the Sphingobacteriaceae family. Using a database that contains experimentally verified plastic-active enzymes (PAZymes), twenty-seven putative bacterial polyethylene terephthalate (PET)-active enzymes (i.e., alpha/beta-fold hydrolases) were detected in all MAGs. A maximum of five putative PETases were found in MAG_3858, and two PETases were found to be encoded by A. colombiense. In conclusion, we demonstrate that lignocellulose-enriched liquid cultures coupled with genome-resolved metagenomics are suitable approaches to unveil the hidden bacterial diversity and its polymer-degrading potential in Andean soil ecosystems.
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Affiliation(s)
- Laura Díaz-García
- Department of Chemical and Biological Engineering, Advanced Biomanufacturing Centre, University of Sheffield, UK
| | - Maria Chuvochina
- The University of Queensland, School of Chemistry and Molecular Biosciences, Australian Centre for Ecogenomics, Brisbane, Queensland, Australia
| | - Golo Feuerriegel
- Department of Microbiology and Biotechnology, University of Hamburg, Hamburg, Germany
| | - Boyke Bunk
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Cathrin Spröer
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Wolfgang R Streit
- Department of Microbiology and Biotechnology, University of Hamburg, Hamburg, Germany
| | - Luis M Rodriguez-R
- Department of Microbiology and Digital Science Center (DiSC), University of Innsbruck, Innsbruck, Austria
| | - Jörg Overmann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany; Braunschweig University of Technology, Braunschweig, Germany
| | - Diego Javier Jiménez
- Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia; Microbiomes and Bioenergy Research Group, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia.
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7
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Liu P, Zheng Y, Yuan Y, Han Y, Su T, Qi Q. Upcycling of PET oligomers from chemical recycling processes to PHA by microbial co-cultivation. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 172:51-59. [PMID: 37714010 DOI: 10.1016/j.wasman.2023.08.048] [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: 07/01/2023] [Revised: 08/23/2023] [Accepted: 08/31/2023] [Indexed: 09/17/2023]
Abstract
Polyethylene terephthalate (PET) is the most widely consumed polyester plastic and can be recycled by many chemical processes, of which glycolysis is most cost-effective and commercially viable. However, PET glycolysis produces oligomers due to incomplete depolymerization, which are undesirable by-products and require proper disposal. In this study, the PET oligomers from chemical recycling processes were completely bio-depolymerized into monomers and then used for the biosynthesis of biodegradable plastics polyhydroxyalkanoates (PHA) by co-cultivation of two engineered microorganisms Escherichia coli BL21 (DE3)-LCCICCG and Pseudomonas putida KT2440-ΔRDt-ΔZP46C-M. E. coli BL21 (DE3)-LCCICCG was used to secrete the PET hydrolase LCCICCG into the medium to directly depolymerize PET oligomers. P. putida KT2440-ΔRDt-ΔZP46C-M that mastered the metabolism of aromatic compounds was engineered to accelerate the hydrolysis of intermediate products mono-2-(hydroxyethyl) terephthalate (MHET) by expressing IsMHETase, and biosynthesize PHA using ultimate products terephthalate and ethylene glycol depolymerized from the PET oligomers. The population ratios of the two microorganisms during the co-cultivation were characterized by fluorescent reporter system, and revealed the collaboration of the two microorganisms to bio-depolymerize and bioconversion of PET oligomers in a single process. This study provides a biological strategy for the upcycling of PET oligomers and promotes the plastic circular economy.
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Affiliation(s)
- Pan Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Yi Zheng
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Yingbo Yuan
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Yuanfei Han
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Tianyuan Su
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China.
| | - Qingsheng Qi
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China.
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Williams GB, Ma H, Khusnutdinova AN, Yakunin AF, Golyshin PN. Harnessing extremophilic carboxylesterases for applications in polyester depolymerisation and plastic waste recycling. Essays Biochem 2023; 67:715-729. [PMID: 37334661 PMCID: PMC10423841 DOI: 10.1042/ebc20220255] [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: 03/19/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/20/2023]
Abstract
The steady growth in industrial production of synthetic plastics and their limited recycling have resulted in severe environmental pollution and contribute to global warming and oil depletion. Currently, there is an urgent need to develop efficient plastic recycling technologies to prevent further environmental pollution and recover chemical feedstocks for polymer re-synthesis and upcycling in a circular economy. Enzymatic depolymerization of synthetic polyesters by microbial carboxylesterases provides an attractive addition to existing mechanical and chemical recycling technologies due to enzyme specificity, low energy consumption, and mild reaction conditions. Carboxylesterases constitute a diverse group of serine-dependent hydrolases catalysing the cleavage and formation of ester bonds. However, the stability and hydrolytic activity of identified natural esterases towards synthetic polyesters are usually insufficient for applications in industrial polyester recycling. This necessitates further efforts on the discovery of robust enzymes, as well as protein engineering of natural enzymes for enhanced activity and stability. In this essay, we discuss the current knowledge of microbial carboxylesterases that degrade polyesters (polyesterases) with focus on polyethylene terephthalate (PET), which is one of the five major synthetic polymers. Then, we briefly review the recent progress in the discovery and protein engineering of microbial polyesterases, as well as developing enzyme cocktails and secreted protein expression for applications in the depolymerisation of polyester blends and mixed plastics. Future research aimed at the discovery of novel polyesterases from extreme environments and protein engineering for improved performance will aid developing efficient polyester recycling technologies for the circular plastics economy.
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Affiliation(s)
- Gwion B Williams
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Hairong Ma
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Anna N Khusnutdinova
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Alexander F Yakunin
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Peter N Golyshin
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
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9
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Okal EJ, Heng G, Magige EA, Khan S, Wu S, Ge Z, Zhang T, Mortimer PE, Xu J. Insights into the mechanisms involved in the fungal degradation of plastics. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 262:115202. [PMID: 37390726 DOI: 10.1016/j.ecoenv.2023.115202] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 06/13/2023] [Accepted: 06/27/2023] [Indexed: 07/02/2023]
Abstract
Fungi are considered among the most efficient microbial degraders of plastics, as they produce salient enzymes and can survive on recalcitrant compounds with limited nutrients. In recent years, studies have reported numerous species of fungi that can degrade different types of plastics, yet there remain many gaps in our understanding of the processes involved in biodegradation. In addition, many unknowns need to be resolved regarding the fungal enzymes responsible for plastic fragmentation and the regulatory mechanisms which fungi use to hydrolyse, assimilate and mineralize synthetic plastics. This review aims to detail the main methods used in plastic hydrolysis by fungi, key enzymatic and molecular mechanisms, chemical agents that enhance the enzymatic breakdown of plastics, and viable industrial applications. Considering that polymers such as lignin, bioplastics, phenolics, and other petroleum-based compounds exhibit closely related characteristics in terms of hydrophobicity and structure, and are degraded by similar fungal enzymes as plastics, we have reasoned that genes that have been reported to regulate the biodegradation of these compounds or their homologs could equally be involved in the regulation of plastic degrading enzymes in fungi. Thus, this review highlights and provides insight into some of the most likely regulatory mechanisms by which fungi degrade plastics, target enzymes, genes, and transcription factors involved in the process, as well as key limitations to industrial upscaling of plastic biodegradation and biological approaches that can be employed to overcome these challenges.
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Affiliation(s)
- Eyalira Jacob Okal
- Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China
| | - Gui Heng
- Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China.
| | - Ephie A Magige
- University of Chinese Academy of Sciences, Beijing 100049, China; CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Sehroon Khan
- Department of Biotechnology, Faculty of Natural Sciences, University of Science and Technology Bannu, 28100 Bannu, Khyber Pakhtunkhwa, Pakistan
| | - Shixi Wu
- Science and Technology on Aerospace Chemical Power Laboratory, Hubei Institute of Aerospace Chemotechnology, Xiangyang 441003, Hubei, China
| | - Zhiqiang Ge
- Science and Technology on Aerospace Chemical Power Laboratory, Hubei Institute of Aerospace Chemotechnology, Xiangyang 441003, Hubei, China
| | - Tianfu Zhang
- Science and Technology on Aerospace Chemical Power Laboratory, Hubei Institute of Aerospace Chemotechnology, Xiangyang 441003, Hubei, China
| | - Peter E Mortimer
- Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China.
| | - Jianchu Xu
- Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China.
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10
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Klose L, Meyer-Heydecke N, Wongwattanarat S, Chow J, Pérez García P, Carré C, Streit W, Antranikian G, Romero AM, Liese A. Towards Sustainable Recycling of Epoxy-Based Polymers: Approaches and Challenges of Epoxy Biodegradation. Polymers (Basel) 2023; 15:2653. [PMID: 37376299 DOI: 10.3390/polym15122653] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Epoxy resins are highly valued for their remarkable mechanical and chemical properties and are extensively used in various applications such as coatings, adhesives, and fiber-reinforced composites in lightweight construction. Composites are especially important for the development and implementation of sustainable technologies such as wind power, energy-efficient aircrafts, and electric cars. Despite their advantages, their non-biodegradability raises challenges for the recycling of polymer and composites in particular. Conventional methods employed for epoxy recycling are characterized by their high energy consumption and the utilization of toxic chemicals, rendering them rather unsustainable. Recent progress has been made in the field of plastic biodegradation, which is considered more sustainable than energy-intensive mechanical or thermal recycling methods. However, the current successful approaches in plastic biodegradation are predominantly focused on polyester-based polymers, leaving more recalcitrant plastics underrepresented in this area of research. Epoxy polymers, characterized by their strong cross-linking and predominantly ether-based backbone, exhibit a highly rigid and durable structure, placing them within this category. Therefore, the objective of this review paper is to examine the various approaches that have been employed for the biodegradation of epoxy so far. Additionally, the paper sheds light on the analytical techniques utilized in the development of these recycling methods. Moreover, the review addresses the challenges and opportunities entailed in epoxy recycling through bio-based approaches.
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Affiliation(s)
- Leon Klose
- Institute of Technical Biocatalysis, Hamburg University of Technology, 21073 Hamburg, Germany
| | - Neele Meyer-Heydecke
- Institute of Technical Biocatalysis, Hamburg University of Technology, 21073 Hamburg, Germany
| | - Sasipa Wongwattanarat
- Department of Microbiology and Biotechnology, University of Hamburg, 22609 Hamburg, Germany
| | - Jennifer Chow
- Department of Microbiology and Biotechnology, University of Hamburg, 22609 Hamburg, Germany
| | - Pablo Pérez García
- Department of Microbiology and Biotechnology, University of Hamburg, 22609 Hamburg, Germany
| | - Camille Carré
- Airbus Defence and Space GmbH, Central Research and Technology, 81663 Munich, Germany
| | - Wolfgang Streit
- Department of Microbiology and Biotechnology, University of Hamburg, 22609 Hamburg, Germany
| | - Garabed Antranikian
- Institute of Technical Biocatalysis, Hamburg University of Technology, 21073 Hamburg, Germany
| | - Ana Malvis Romero
- Institute of Technical Biocatalysis, Hamburg University of Technology, 21073 Hamburg, Germany
| | - Andreas Liese
- Institute of Technical Biocatalysis, Hamburg University of Technology, 21073 Hamburg, Germany
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Carr CM, Keller MB, Paul B, Schubert SW, Clausen KSR, Jensen K, Clarke DJ, Westh P, Dobson ADW. Purification and biochemical characterization of SM14est, a PET-hydrolyzing enzyme from the marine sponge-derived Streptomyces sp. SM14. Front Microbiol 2023; 14:1170880. [PMID: 37250061 PMCID: PMC10213408 DOI: 10.3389/fmicb.2023.1170880] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/21/2023] [Indexed: 05/31/2023] Open
Abstract
The successful enzymatic degradation of polyester substrates has fueled worldwide investigation into the treatment of plastic waste using bio-based processes. Within this realm, marine-associated microorganisms have emerged as a promising source of polyester-degrading enzymes. In this work, we describe the hydrolysis of the synthetic polymer PET by SM14est, a polyesterase which was previously identified from Streptomyces sp. SM14, an isolate of the marine sponge Haliclona simulans. The PET hydrolase activity of purified SM14est was assessed using a suspension-based assay and subsequent analysis of reaction products by UV-spectrophotometry and RP-HPLC. SM14est displayed a preference for high salt conditions, with activity significantly increasing at sodium chloride concentrations from 100 mM up to 1,000 mM. The initial rate of PET hydrolysis by SM14est was determined to be 0.004 s-1 at 45°C, which was increased by 5-fold to 0.02 s-1 upon addition of 500 mM sodium chloride. Sequence alignment and structural comparison with known PET hydrolases, including the marine halophile PET6, and the highly efficient, thermophilic PHL7, revealed conserved features of interest. Based on this work, SM14est emerges as a useful enzyme that is more similar to key players in the area of PET hydrolysis, like PHL7 and IsPETase, than it is to its marine counterparts. Salt-tolerant polyesterases such as SM14est are potentially valuable in the biological degradation of plastic particles that readily contaminate marine ecosystems and industrial wastewaters.
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Affiliation(s)
- Clodagh M. Carr
- School of Microbiology, University College Cork, Cork, Ireland
- SSPC-SFI Research Centre for Pharmaceuticals, University College Cork, Cork, Ireland
| | - Malene B. Keller
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Bijoya Paul
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Sune W. Schubert
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Kristine S. R. Clausen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | | | - David J. Clarke
- School of Microbiology, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Alan D. W. Dobson
- School of Microbiology, University College Cork, Cork, Ireland
- SSPC-SFI Research Centre for Pharmaceuticals, University College Cork, Cork, Ireland
- Environmental Research Institute, University College Cork, Cork, Ireland
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Díaz Rodríguez CA, Díaz-García L, Bunk B, Spröer C, Herrera K, Tarazona NA, Rodriguez-R LM, Overmann J, Jiménez DJ. Novel bacterial taxa in a minimal lignocellulolytic consortium and their potential for lignin and plastics transformation. ISME COMMUNICATIONS 2022; 2:89. [PMID: 37938754 PMCID: PMC9723784 DOI: 10.1038/s43705-022-00176-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/09/2022] [Accepted: 09/13/2022] [Indexed: 11/09/2023]
Abstract
The understanding and manipulation of microbial communities toward the conversion of lignocellulose and plastics are topics of interest in microbial ecology and biotechnology. In this study, the polymer-degrading capability of a minimal lignocellulolytic microbial consortium (MELMC) was explored by genome-resolved metagenomics. The MELMC was mostly composed (>90%) of three bacterial members (Pseudomonas protegens; Pristimantibacillus lignocellulolyticus gen. nov., sp. nov; and Ochrobactrum gambitense sp. nov) recognized by their high-quality metagenome-assembled genomes (MAGs). Functional annotation of these MAGs revealed that Pr. lignocellulolyticus could be involved in cellulose and xylan deconstruction, whereas Ps. protegens could catabolize lignin-derived chemical compounds. The capacity of the MELMC to transform synthetic plastics was assessed by two strategies: (i) annotation of MAGs against databases containing plastic-transforming enzymes; and (ii) predicting enzymatic activity based on chemical structural similarities between lignin- and plastics-derived chemical compounds, using Simplified Molecular-Input Line-Entry System and Tanimoto coefficients. Enzymes involved in the depolymerization of polyurethane and polybutylene adipate terephthalate were found to be encoded by Ps. protegens, which could catabolize phthalates and terephthalic acid. The axenic culture of Ps. protegens grew on polyhydroxyalkanoate (PHA) nanoparticles and might be a suitable species for the industrial production of PHAs in the context of lignin and plastic upcycling.
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Affiliation(s)
- Carlos Andrés Díaz Rodríguez
- Microbiomes and Bioenergy Research Group, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Laura Díaz-García
- Microbiomes and Bioenergy Research Group, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
- Department of Chemical and Biological Engineering, Advanced Biomanufacturing Centre, University of Sheffield, Sheffield, UK
| | - Boyke Bunk
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Cathrin Spröer
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Katherine Herrera
- Department of Civil and Environmental Engineering, Universidad de los Andes, Bogotá, Colombia
| | | | - Luis M Rodriguez-R
- Department of Microbiology and Digital Science Center (DiSC), University of Innsbruck, Innsbruck, Austria
| | - Jörg Overmann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
- Braunschweig University of Technology, Braunschweig, Germany
| | - Diego Javier Jiménez
- Microbiomes and Bioenergy Research Group, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia.
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