1
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Shalem A, Yehezkeli O, Fishman A. Enzymatic degradation of polylactic acid (PLA). Appl Microbiol Biotechnol 2024; 108:413. [PMID: 38985324 PMCID: PMC11236915 DOI: 10.1007/s00253-024-13212-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 07/11/2024]
Abstract
Environmental concerns arising from the increasing use of polluting plastics highlight polylactic acid (PLA) as a promising eco-friendly alternative. PLA is a biodegradable polyester that can be produced through the fermentation of renewable resources. Together with its excellent properties, suitable for a wide range of applications, the use of PLA has increased significantly over the years and is expected to further grow. However, insufficient degradability under natural conditions emphasizes the need for the exploration of biodegradation mechanisms, intending to develop more efficient techniques for waste disposal and recycling or upcycling. Biodegradation occurs through the secretion of depolymerizing enzymes, mainly proteases, lipases, cutinases, and esterases, by various microorganisms. This review focuses on the enzymatic degradation of PLA and presents different enzymes that were isolated and purified from natural PLA-degrading microorganisms, or recombinantly expressed. The review depicts the main characteristics of the enzymes, including recent advances and analytical methods used to evaluate enantiopurity and depolymerizing activity. While complete degradation of solid PLA particles is still difficult to achieve, future research and improvement of enzyme properties may provide an avenue for the development of advanced procedures for PLA degradation and upcycling, utilizing its building blocks for further applications as envisaged by circular economy principles. KEY POINTS: • Enzymes can be promisingly utilized for PLA upcycling. • Natural and recombinant PLA depolymerases and methods for activity evaluation are summarized. • Approaches to improve enzymatic degradation of PLA are discussed.
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Affiliation(s)
- Adi Shalem
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, 3200003, Haifa, Israel
| | - Omer Yehezkeli
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, 3200003, Haifa, Israel
| | - Ayelet Fishman
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, 3200003, Haifa, Israel.
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2
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Wang Y, Zhang W, Wang Z, Lyu S. A polylactic acid degrading lipase from Bacillus safensis: Characterization and structural analysis. Int J Biol Macromol 2024; 268:131916. [PMID: 38679264 DOI: 10.1016/j.ijbiomac.2024.131916] [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: 10/26/2023] [Revised: 02/29/2024] [Accepted: 04/25/2024] [Indexed: 05/01/2024]
Abstract
A polylactic acid degrading triacylglycerol lipase (TGL) was identified from Bacillus safensis based on genome annotation and validated by real-time quantitative PCR. TGL displayed optimal activity at pH 9.0 and 55 °C. It maintained stability at pH 9.0 and temperatures 45 °C. The activity of TGL was found to benefit from the presence of potassium sodium ions, and low concentrations of Triton X-100. The TGL could erode the surface of polylactic acid films and increase its hydrophilicity. The hydrolysis products of polylactic acid by TGL were lactate monomer and dimer. TGL contains a classical catalytic triad structure of lipase (Ser77, Asp133, and His156) and an Ala-X-Ser-X-Gly sequence. Compared with some lipases produced by the same genus Bacillus, TGL is highly conserved in its amino acid sequence, mainly reflected in the amino acid residues that exercise the enzyme activity, including the catalytic activity center and the substrate binding sites.
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Affiliation(s)
- Yujun Wang
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, China
| | - Wanting Zhang
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, China
| | - Zhanyong Wang
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, China; Liaoning Provincial Key Laboratory for Extreme-environmental Microbiology, Shenyang Agricultural University, Shenyang 110866, China.
| | - Shuxia Lyu
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, China.
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3
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Tang B, Zhang L, Salam M, Yang B, He Q, Yang Y, Li H. Revealing the environmental hazard posed by biodegradable microplastics in aquatic ecosystems: An investigation of polylactic acid's effects on Microcystis aeruginosa. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123347. [PMID: 38215868 DOI: 10.1016/j.envpol.2024.123347] [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: 10/20/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 01/14/2024]
Abstract
The influence of petroleum-based microplastics (MPs) on phytoplankton has been extensively studied, while research on the impact of biodegradable MPs, derived from alternative plastics to contest the environmental crisis, remains limited. This study performed a 63 days co-incubation experiment to assess the effect of polylactic acid MPs (PLA-MPs) on the growth, physiology, and carbon utilization of M. aeruginosa and the change in PLA-MPs surface properties. The results showed that despite PLA-MPs induced oxidative stress and caused membrane damage in M. aeruginosa, the presence of PLA-MPs (10, 50, and 200 mg/L) triggered significant increases (p < 0.05) in the density of M. aeruginosa after 63 days. Specifically, the algal densities upon 50 and 200 mg/L PLA-MPs exposure were increased by 20.91% and 36.31% relative to the control, respectively. Meanhwhile, the reduced C/O ratio on PLA-MPs surface and change in PLA-MPs morphological characterization, which is responsible for substantially increase in the aquatic dissolved inorganic carbon concentration during the co-incubation, implying the degradation of PLA-MPs; thus, provided sufficient carbon resources that M. aeruginosa could assimilate. This was in line with the declined intracellular carbonic anhydrase content in M. aeruginosa. This study is the first attempt to uncover the interaction between PLA-MPs and M. aeruginosa, and the finding that their interaction promotes the degrading of PLA-MPs meanwhile favoring M. aeruginosa growth will help elucidate the potential risk of biodegradable MPs in aquatic environment.
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Affiliation(s)
- Bingran Tang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China
| | - Lixue Zhang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China
| | - Muhammad Salam
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Bing Yang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Ecological and Environment Monitoring Center of Chongqing, Chongqing, 401147, China
| | - Qiang He
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China
| | - Yongchuan Yang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China
| | - Hong Li
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China.
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4
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Lee GH, Kim DW, Jin YH, Kim SM, Lim ES, Cha MJ, Ko JK, Gong G, Lee SM, Um Y, Han SO, Ahn JH. Biotechnological Plastic Degradation and Valorization Using Systems Metabolic Engineering. Int J Mol Sci 2023; 24:15181. [PMID: 37894861 PMCID: PMC10607142 DOI: 10.3390/ijms242015181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 10/10/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023] Open
Abstract
Various kinds of plastics have been developed over the past century, vastly improving the quality of life. However, the indiscriminate production and irresponsible management of plastics have led to the accumulation of plastic waste, emerging as a pressing environmental concern. To establish a clean and sustainable plastic economy, plastic recycling becomes imperative to mitigate resource depletion and replace non-eco-friendly processes, such as incineration. Although chemical and mechanical recycling technologies exist, the prevalence of composite plastics in product manufacturing complicates recycling efforts. In recent years, the biodegradation of plastics using enzymes and microorganisms has been reported, opening a new possibility for biotechnological plastic degradation and bio-upcycling. This review provides an overview of microbial strains capable of degrading various plastics, highlighting key enzymes and their role. In addition, recent advances in plastic waste valorization technology based on systems metabolic engineering are explored in detail. Finally, future perspectives on systems metabolic engineering strategies to develop a circular plastic bioeconomy are discussed.
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Affiliation(s)
- Ga Hyun Lee
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Do-Wook Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Yun Hui Jin
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Sang Min Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Eui Seok Lim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Min Ji Cha
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Ja Kyong Ko
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Gyeongtaek Gong
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Sun-Mi Lee
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Sung Ok Han
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Jung Ho Ahn
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
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5
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Kumar R, Sadeghi K, Jang J, Seo J. Mechanical, chemical, and bio-recycling of biodegradable plastics: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 882:163446. [PMID: 37075991 DOI: 10.1016/j.scitotenv.2023.163446] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/07/2023] [Accepted: 04/07/2023] [Indexed: 05/03/2023]
Abstract
The extensive use of petroleum-based non-biodegradable plastics for various applications has led to global concerns regarding the severe environmental issues associated with them. However, biodegradable plastics are emerging as green alternatives to petroleum-based non-biodegradable plastics. Biodegradable plastics, which include bio-based and petroleum-based biodegradable polymers, exhibit advantageous properties such as renewability, biocompatibility, and non-toxicity. Furthermore, certain biodegradable plastics are compatible with existing recycling streams intended for conventional plastics and are biodegradable in controlled and/or predicted environments. Recycling biodegradable plastics before their end-of-life (EOL) degradation further enhances their sustainability and reduces their carbon footprint. Since the production of biodegradable plastic is increasing and these materials will coexist with conventional plastics for many years to come, it is essential to identify the optimal recycling options for each of the most prevalent biodegradable plastics. The substitution of virgin biodegradable plastics by their recyclates leads to higher savings in the primary energy demand and reduces global warming impact. This review covers the current state of the mechanical, chemical, and bio-recycling of post-industrial and post-consumer waste of biodegradable plastics and their related composites. The effects of recycling on the chemical structure and thermomechanical properties of biodegradable plastics are also reported. Additionally, the improvement of biodegradable plastics by blending them with other polymers and nanoparticles is comprehensively discussed. Finally, the status of bioplastic usage, life cycle assessment, EOL management, bioplastic market, and the challenges associated with the recyclability of biodegradable plastics are addressed. This review gives comprehensive insights into the recycling processes that may be employed for the recycling of biodegradable plastics.
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Affiliation(s)
- Ritesh Kumar
- Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do 26493, South Korea
| | - Kambiz Sadeghi
- Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do 26493, South Korea
| | - Jaeyoung Jang
- Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do 26493, South Korea
| | - Jongchul Seo
- Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do 26493, South Korea.
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6
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Tournier V, Duquesne S, Guillamot F, Cramail H, Taton D, Marty A, André I. Enzymes' Power for Plastics Degradation. Chem Rev 2023; 123:5612-5701. [PMID: 36916764 DOI: 10.1021/acs.chemrev.2c00644] [Citation(s) in RCA: 56] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Plastics are everywhere in our modern way of living, and their production keeps increasing every year, causing major environmental concerns. Nowadays, the end-of-life management involves accumulation in landfills, incineration, and recycling to a lower extent. This ecological threat to the environment is inspiring alternative bio-based solutions for plastic waste treatment and recycling toward a circular economy. Over the past decade, considerable efforts have been made to degrade commodity plastics using biocatalytic approaches. Here, we provide a comprehensive review on the recent advances in enzyme-based biocatalysis and in the design of related biocatalytic processes to recycle or upcycle commodity plastics, including polyesters, polyamides, polyurethanes, and polyolefins. We also discuss scope and limitations, challenges, and opportunities of this field of research. An important message from this review is that polymer-assimilating enzymes are very likely part of the solution to reaching a circular plastic economy.
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Affiliation(s)
- Vincent Tournier
- Carbios, Parc Cataroux-Bâtiment B80, 8 rue de la Grolière, 63100 Clermont-Ferrand, France
| | - Sophie Duquesne
- Toulouse Biotechnology Institute, TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France, 135, avenue de Rangueil, F-31077 Toulouse Cedex 04, France
| | - Frédérique Guillamot
- Carbios, Parc Cataroux-Bâtiment B80, 8 rue de la Grolière, 63100 Clermont-Ferrand, France
| | - Henri Cramail
- Université Bordeaux, CNRS, Bordeaux INP, LCPO, 16 Avenue Pey-Berland, 33600 Pessac, France
| | - Daniel Taton
- Université Bordeaux, CNRS, Bordeaux INP, LCPO, 16 Avenue Pey-Berland, 33600 Pessac, France
| | - Alain Marty
- Carbios, Parc Cataroux-Bâtiment B80, 8 rue de la Grolière, 63100 Clermont-Ferrand, France
| | - Isabelle André
- Toulouse Biotechnology Institute, TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France, 135, avenue de Rangueil, F-31077 Toulouse Cedex 04, France
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7
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Cannon JA, Reynolds TB. Synergistic Mutations Create Bacillus Subtilisin Variants with Enhanced Poly-l-Lactic Acid Depolymerization Activity. Biomacromolecules 2023; 24:1141-1154. [PMID: 36780360 DOI: 10.1021/acs.biomac.2c01198] [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: 02/14/2023]
Abstract
Enzymatic recycling of poly-l-lactic acid (PLLA) plastic has recently become an area of interest; however, investigation of enzymatic mechanisms and engineering strategies to improve activity remains limited. In this study, we have identified a subtilisin from Bacillus pumilus that has the ability to depolymerize high-molecular-weight PLLA. We performed a comparative, mutational analysis of this enzyme with a less active homologue from Bacillus subtilis to determine residues favored for activity. Our results demonstrate that both enzymes contain residues favored for PLLA depolymerization, with the generation of several hyperactive variants. In silico modeling suggests that increases in activity are due to opening of the binding pockets and increased surface hydrophobicity. Combinations of hyperactive mutations have synergistic effects with the generation of subtilisin variants with 830- and 184-fold increases in activity for B. subtilis and B. pumilus subtilisins, respectively. One B. pumilus subtilisin variant can visibly dissolve high-molecular-weight PLLA films.
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Affiliation(s)
- Jordan A Cannon
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, Tennessee 37996, United States
| | - Todd B Reynolds
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, Tennessee 37996, United States
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8
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Wang Y, Hu T, Zhang W, Lin J, Wang Z, Lyu S, Tong H. Biodegradation of polylactic acid by a mesophilic bacteria Bacillus safensis. CHEMOSPHERE 2023; 318:137991. [PMID: 36716940 DOI: 10.1016/j.chemosphere.2023.137991] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
A mesophilic bacterial strain, Bacillus safensis PLA1006, was isolated from landfill soil and was tested for growth on polylactic acid (PLA) emulsion medium. The strain formed clear zones on the medium and produced protease and lipase. The macroscopic morphology of the PLA films was not changed significantly after treatment with Bacillus safensis PLA1006 but the films were whitened. Weight loss of PLA films was about 8% after 30 days of incubation with Bacillus safensis PLA1006 in mineral salt medium. Scanning electron microscopy revealed etching on the surface of PLA film treated by Bacillus safensis PLA1006. This also caused an increase in hydrophilicity of the PLA films surface. Attenuated total reflectance - Fourier transform infrared spectroscopy analysis of PLA films after treated by Bacillus safensis PLA1006 showed no new absorption peaks but a decrease in the intensity of all absorption peaks. The hydrolysis products of PLA by the strain contained monomers and oligomers of lactic acid. Zymogram detection showed that proteases may play a role in the degradation of PLA.
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Affiliation(s)
- Yujun Wang
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, China
| | - Ting Hu
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, China
| | - Wanting Zhang
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, China
| | - Jinwei Lin
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, China
| | - Zhanyong Wang
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, China; Liaoning Provincial Key Laboratory for Extreme-environmental Microbiology, Shenyang Agricultural University, Shenyang, 110866, China.
| | - Shuxia Lyu
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, China.
| | - Haibin Tong
- Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, College of Life and Environmental Science, Wenzhou University, Wenzhou, 325035, China.
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Wei S, Zhao Y, Zhou R, Lin J, Su T, Tong H, Wang Z. Biodegradation of polybutylene adipate-co-terephthalate by Priestia megaterium, Pseudomonas mendocina, and Pseudomonas pseudoalcaligenes following incubation in the soil. CHEMOSPHERE 2022; 307:135700. [PMID: 35850225 DOI: 10.1016/j.chemosphere.2022.135700] [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: 06/08/2022] [Revised: 06/29/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
Soil that contained polybutylene adipate-co-terephthalate (PBAT) was incubated with Priestia megaterium, Pseudomonas mendocina, and Pseudomonas pseudoalcaligenes to improve the biodegradative process of this polymer. The mixture of Pr. megaterium and Ps. mendocina was highly effective at biodegrading the PBAT, and after eight weeks of soil incubation, approximately 84% of the PBAT film weight was lost. Mixtures of the other two species also positively affected the synergistic degradation of PBAT film in the soil, but the mixture of three species had a negative effect. The residual PBAT film microstructure clearly demonstrated the degradation of PBAT, and the degree of degradation was related to the different species. Cleavage of the PBAT film ester bond after soil microbial action affected its properties. The incubation of PBAT in soil that contained these species affected soil dehydrogenase and soil lipase in particular. The secretion of lipase by these species could play an important role in the degradation of PBAT in the soil.
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Affiliation(s)
- Shiwei Wei
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, China
| | - Yujin Zhao
- School of Petrochemical Engineering, Liaoning Petrochemical University, Fushun, 113001, China
| | - Ruimin Zhou
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, China
| | - Jingwei Lin
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, China
| | - Tingting Su
- School of Petrochemical Engineering, Liaoning Petrochemical University, Fushun, 113001, China
| | - Haibin Tong
- Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, College of Life and Environmental Science, Wenzhou University, Wenzhou, 325035, China.
| | - Zhanyong Wang
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, China.
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10
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Bher A, Mayekar PC, Auras RA, Schvezov CE. Biodegradation of Biodegradable Polymers in Mesophilic Aerobic Environments. Int J Mol Sci 2022; 23:12165. [PMID: 36293023 PMCID: PMC9603655 DOI: 10.3390/ijms232012165] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/03/2022] [Accepted: 10/07/2022] [Indexed: 08/29/2023] Open
Abstract
Finding alternatives to diminish plastic pollution has become one of the main challenges of modern life. A few alternatives have gained potential for a shift toward a more circular and sustainable relationship with plastics. Biodegradable polymers derived from bio- and fossil-based sources have emerged as one feasible alternative to overcome inconveniences associated with the use and disposal of non-biodegradable polymers. The biodegradation process depends on the environment's factors, microorganisms and associated enzymes, and the polymer properties, resulting in a plethora of parameters that create a complex process whereby biodegradation times and rates can vary immensely. This review aims to provide a background and a comprehensive, systematic, and critical overview of this complex process with a special focus on the mesophilic range. Activity toward depolymerization by extracellular enzymes, biofilm effect on the dynamic of the degradation process, CO2 evolution evaluating the extent of biodegradation, and metabolic pathways are discussed. Remarks and perspectives for potential future research are provided with a focus on the current knowledge gaps if the goal is to minimize the persistence of plastics across environments. Innovative approaches such as the addition of specific compounds to trigger depolymerization under particular conditions, biostimulation, bioaugmentation, and the addition of natural and/or modified enzymes are state-of-the-art methods that need faster development. Furthermore, methods must be connected to standards and techniques that fully track the biodegradation process. More transdisciplinary research within areas of polymer chemistry/processing and microbiology/biochemistry is needed.
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Affiliation(s)
- Anibal Bher
- School of Packaging, Michigan State University, East Lansing, MI 48824, USA
- Instituto de Materiales de Misiones, CONICET-UNaM, Posadas 3300, Misiones, Argentina
| | - Pooja C. Mayekar
- School of Packaging, Michigan State University, East Lansing, MI 48824, USA
| | - Rafael A. Auras
- School of Packaging, Michigan State University, East Lansing, MI 48824, USA
| | - Carlos E. Schvezov
- Instituto de Materiales de Misiones, CONICET-UNaM, Posadas 3300, Misiones, Argentina
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11
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Liao J, Chen Q. Biodegradable plastics in the air and soil environment: Low degradation rate and high microplastics formation. JOURNAL OF HAZARDOUS MATERIALS 2021; 418:126329. [PMID: 34118549 DOI: 10.1016/j.jhazmat.2021.126329] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 06/12/2023]
Abstract
In recent years, the promotion and use of biodegradable plastics (BPs) are growing into a general trend. Here the degradation performance of different types of BPs was investigated in the natural environment. Their degradation levels followed the order of pure BPs> BP blends> claimed "BP"≈ non-biodegradable plastic after 6-month incubation. Photo- and biodegradation were the main degradation mechanisms of these plastics in the air and soil, respectively. Poly(p-dioxanone) (PPDO) exhibited the highest weight loss potentials in both air (54.7 ± 9.1%) and soil (56.8 ± 4.8%), due to its special ether bond and the rich and diverse microorganisms on its biofilms. The microbiota on PPDO was distinct and enriched with Chloroflexi and Firmicutes that responsible for carbon cycle and organic degradation. The weight loss was only 1.1-8.0% for poly(lactic acid), and 0.8-6.8% for poly(butylene adipate-co-terephthalate), and other plastics are basically non-degradable. Of note, numerous microplastics were formed after PPDO degradation, with 441 ± 326 and 2103 ± 131 item/g plastic in the air and soil, respectively. Taken together, the monitoring of BP biodegradation in the natural environment is of vital importance, and it is risky to promote large-scale application of BPs if the knowledge gap of their environmental behavior has not been well addressed.
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Affiliation(s)
- Jin Liao
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 500 Dongchuan Road, Minhang District, Shanghai 200241, China; Shanghai Polar Moment Science and Technology Education Company, Shanghai 200433, China
| | - Qiqing Chen
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 500 Dongchuan Road, Minhang District, Shanghai 200241, China.
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12
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Boonluksiri Y, Prapagdee B, Sombatsompop N. Promotion of polylactic acid biodegradation by a combined addition of PLA-degrading bacterium and nitrogen source under submerged and soil burial conditions. Polym Degrad Stab 2021. [DOI: 10.1016/j.polymdegradstab.2021.109562] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Gambarini V, Pantos O, Kingsbury JM, Weaver L, Handley KM, Lear G. Phylogenetic Distribution of Plastic-Degrading Microorganisms. mSystems 2021; 6:e01112-20. [PMID: 33468707 PMCID: PMC7820669 DOI: 10.1128/msystems.01112-20] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/04/2021] [Indexed: 01/08/2023] Open
Abstract
The number of plastic-degrading microorganisms reported is rapidly increasing, making it possible to explore the conservation and distribution of presumed plastic-degrading traits across the diverse microbial tree of life. Putative degraders of conventional high-molecular-weight polymers, including polyamide, polystyrene, polyvinylchloride, and polypropylene, are spread widely across bacterial and fungal branches of the tree of life, although evidence for plastic degradation by a majority of these taxa appears limited. In contrast, we found strong degradation evidence for the synthetic polymer polylactic acid (PLA), and the microbial species related to its degradation are phylogenetically conserved among the bacterial family Pseudonocardiaceae We collated data on genes and enzymes related to the degradation of all types of plastic to identify 16,170 putative plastic degradation orthologs by mining publicly available microbial genomes. The plastic with the largest number of putative orthologs, 10,969, was the natural polymer polyhydroxybutyrate (PHB), followed by the synthetic polymers polyethylene terephthalate (PET) and polycaprolactone (PCL), with 8,233 and 6,809 orthologs, respectively. These orthologous genes were discovered in the genomes of 6,000 microbial species, and most of them are as yet not identified as plastic degraders. Furthermore, all these species belong to 12 different microbial phyla, of which just 7 phyla have reported degraders to date. We have centralized information on reported plastic-degrading microorganisms within an interactive and updatable phylogenetic tree and database to confirm the global and phylogenetic diversity of putative plastic-degrading taxa and provide new insights into the evolution of microbial plastic-degrading capabilities and avenues for future discovery.IMPORTANCE We have collated the most complete database of microorganisms identified as being capable of degrading plastics to date. These data allow us to explore the phylogenetic distribution of these organisms and their enzymes, showing that traits for plastic degradation are predominantly not phylogenetically conserved. We found 16,170 putative plastic degradation orthologs in the genomes of 12 different phyla, which suggests a vast potential for the exploration of these traits in other taxa. Besides making the database available to the scientific community, we also created an interactive phylogenetic tree that can display all of the collated information, facilitating visualization and exploration of the data. Both the database and the tree are regularly updated to keep up with new scientific reports. We expect that our work will contribute to the field by increasing the understanding of the genetic diversity and evolution of microbial plastic-degrading traits.
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Affiliation(s)
- Victor Gambarini
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Olga Pantos
- The Institute of Environmental Science and Research, Ilam, Christchurch, New Zealand
| | - Joanne M Kingsbury
- The Institute of Environmental Science and Research, Ilam, Christchurch, New Zealand
| | - Louise Weaver
- The Institute of Environmental Science and Research, Ilam, Christchurch, New Zealand
| | - Kim M Handley
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Gavin Lear
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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Satti SM, Shah AA. Polyester-based biodegradable plastics: an approach towards sustainable development. Lett Appl Microbiol 2020; 70:413-430. [PMID: 32086820 DOI: 10.1111/lam.13287] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 11/29/2022]
Abstract
Non-degradability of conventional plastics, filling of landfill sites, raising water and land pollution and rapid depletion of fossil resources have raised the environmental issues and global concerns. The current demand and production of plastics is putting immense pressure on fossil resources, consuming about 6% of the global oil and is expected to grow up to 20%. The polyester-based biodegradable plastics (BPs) are considered as a remedy to the issue of plastics waste in the environment. BPs appear to manage the overflow of plastics by providing new means of waste management system and help in securing the non-renewable resources of nature. This review comprehensively presents the environmental burdens due to conventional plastics as well as production of polyester-based BPs as an alternative to conventional commodity plastics. The diversity of micro-organisms and their enzymes that degrade various polyester-based BPs (PLA, PCL, PHB/PHBV and PET) has also been described in detail. Moreover, the impact of plastics degradation products on soil ecology and ecosystem functions has critically been discussed. The report ends with special focus on future recommendations for the development of sustainable waste management strategies to control pollution due to plastics waste. SIGNIFICANCE AND IMPACT OF THE STUDY: Polyester-based BPs considered as a solution to current plastic waste problem as well as leading polymers in terms of biodegradability and sustainability has been critically discussed. The role of microorganisms and their enzymes involved in the biodegradation of these polymers and ecotoxicological impact of degradation products of BPs on soil microbial community and biogeochemical cycles has also been described. This report will provide an insight on the key research areas to bridge the gap for development of simulated systems as an effective and emerging strategy to divert the overflow of plastic in the environment as well as for the greener solution to the plastic waste management problems.
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Affiliation(s)
- S M Satti
- Department of Microbiology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.,University Institute of Biochemistry and Biotechnology, PMAS Arid Agriculture University, Rawalpindi, Pakistan
| | - A A Shah
- Department of Microbiology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
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Sun C, Li C, Tan H, Zhang Y. Enhancing the durability of poly(lactic acid) composites by nucleated modification. POLYM INT 2019. [DOI: 10.1002/pi.5837] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Ce Sun
- Key Laboratory of Bio‐Based Material Science and Technology, (Ministry of Education)Northeast Forestry University Harbin China
| | - Changxin Li
- Key Laboratory of Bio‐Based Material Science and Technology, (Ministry of Education)Northeast Forestry University Harbin China
| | - Haiyan Tan
- Key Laboratory of Bio‐Based Material Science and Technology, (Ministry of Education)Northeast Forestry University Harbin China
| | - Yanhua Zhang
- Key Laboratory of Bio‐Based Material Science and Technology, (Ministry of Education)Northeast Forestry University Harbin China
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16
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Bubpachat T, Sombatsompop N, Prapagdee B. Isolation and role of polylactic acid-degrading bacteria on degrading enzymes productions and PLA biodegradability at mesophilic conditions. Polym Degrad Stab 2018. [DOI: 10.1016/j.polymdegradstab.2018.03.023] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Bai Z, Liu Y, Su T, Wang Z. Effect of Hydroxyl Monomers on the Enzymatic Degradation of Poly(ethylene succinate), Poly(butylene succinate), and Poly(hexylene succinate). Polymers (Basel) 2018; 10:polym10010090. [PMID: 30966127 PMCID: PMC6414858 DOI: 10.3390/polym10010090] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 01/14/2018] [Accepted: 01/15/2018] [Indexed: 12/03/2022] Open
Abstract
Poly(ethylene succinate) (PES), poly(butylene succinate) (PBS), and poly(hexylene succinate) (PHS), were synthesized using succinic acid and different dihydric alcohols as materials. Enzymatic degradability by cutinase of the three kinds of polyesters was studied, as well as their solid-state properties. The biodegradation behavior relied heavily on the distance between ester groups, crystallinity, and the hydrophilicity-hydrophobicity balance of polyester surfaces. The weight loss through degradation of the three kinds of polyesters with different hydroxyl monomers took place in the order PHS > PBS > PES. The degradation behavior of the polyesters before and after degradation was analyzed by scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction, Fourier transform infrared spectroscopy, gel permeation chromatography, and thermogravimetric analysis. The decrease in relative intensity at 1800–1650 estedpolyesters were degraded simultaneously. The frequencies of the crystalline and amorphous bands were almost identical before and after degradation. Thus, enzymatic degradation did not change the crystalline structure but destroyed it, and the degree of crystallinity markedly decreased. The molecular weight and polydispersity index only changed slightly. The thermal stability of the three kinds of polyesters decreased during enzymatic degradation.
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Affiliation(s)
- Zhenhui Bai
- College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun 113001, China.
| | - Yun Liu
- College of Life S ciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
| | - Tingting Su
- College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun 113001, China.
| | - Zhanyong Wang
- College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun 113001, China.
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18
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Gao Z, Su T, Li P, Wang Z. Biodegradation of P(3HB- co-4HB) powder by Pseudomonas mendocina for preparation low-molecular-mass P(3HB- co-4HB). 3 Biotech 2017; 7:281. [PMID: 28828288 DOI: 10.1007/s13205-017-0824-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/28/2017] [Indexed: 11/28/2022] Open
Abstract
Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) is a biodegradable plastic that is extensively utilized in many fields. In this work, P(3HB-co-4HB) powder was degraded by Pseudomonas mendocina for the preparation of low-molecular-mass (LMW) P(3HB-co-4HB). After degradation, the remaining P(3HB-co-4HB) powder was analyzed via gel permeation chromatography (GPC), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and proton nuclear magnetic resonance (1H NMR) spectroscopy. The degradation of P(3HB-co-4HB) by P. mendocina occurred in two stages: the fast degradation stage (0-8 h) and the slow degradation stage (8-24 h). GPC analysis showed that the molecular weight of P(3HB-co-4HB) gradually decreased with degradation time. After 24 h of degradation, the weight-average molecular weight of P(3HB-co-4HB) was reduced to 4-5 kDa. DSC and XRD analyses both verified that the degree of crystallinity decreased with prolonged degradation time. The melting temperature of the degraded powder, however, remained unchanged. FTIR and 1H NMR analyses of the degraded powder showed that no new material was produced during degradation. Thus, the degradation of P(3HB-co-4HB) by P. mendocina could be used to produce LMW P(3HB-co-4HB) for use in various applications, such as the synthesis of amphiphilic block copolymers.
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Affiliation(s)
- Zhaoying Gao
- College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun, 113001 Liaoning China
| | - Tingting Su
- College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun, 113001 Liaoning China
| | - Ping Li
- College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun, 113001 Liaoning China
| | - Zhanyong Wang
- College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun, 113001 Liaoning China
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Application of Chitinous Materials in Production and Purification of a Poly(l-lactic acid) Depolymerase from Pseudomonas tamsuii TKU015. Polymers (Basel) 2016; 8:polym8030098. [PMID: 30979189 PMCID: PMC6432605 DOI: 10.3390/polym8030098] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 03/14/2016] [Accepted: 03/16/2016] [Indexed: 12/02/2022] Open
Abstract
The management of fishery residues and plastics is considered to be a vital strategy for conserving resources and maintaining the quality of the environment. Poly(l-lactic acid) (PLA) is a commercially promising, renewable, and biodegradable plastic. In this study, a PLA depolymerase was produced in a squid pen powder (SPP) and recycled plastic waste (PLA powder)-containing medium by Pseudomonas tamsuii TKU015, a bacterial strain isolated from Taiwanese soil. This PLA depolymerase had a molecular weight of 58 kDa and was purified to homogeneity from the supernatant of a TKU015 culture. The optimum pH of TKU015 PLA depolymerase is 10, and the optimal temperature of the enzyme is 60 °C. In addition to PLA, TKU015 PLA depolymerase degraded fibrinogen and tributyrin, but did not hydrolyze casein, triolein, and poly(β-hydroxybutyrate). Taken together, these data demonstrate that P. tamsuii TKU015 produces a PLA depolymerase to utilize SPP and polylactide as carbon/nitrogen sources.
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Wang Z, Mao H, Liu H, Su T, Jiang H. Optimization of medium composition for 3-hydroxycarboxylic acid production by Pseudomonas mendocina-biodegraded polyhydroxybutyrate. Biotechnol Appl Biochem 2014; 62:260-7. [PMID: 24919602 DOI: 10.1002/bab.1257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 06/03/2014] [Indexed: 11/09/2022]
Abstract
We optimized the culture medium for 3-hydroxycarboxylic acid production by Pseudomonas mendocina DS-04-T-biodegraded polyhydroxybutyrate (PHB) using the Plackett-Burman design, steepest ascent method, and Box-Behnken design. The optimized concentrations of the constituents of the culture medium were as follows: PHB (7.57 g/L), NH4 Cl (5.0 g/L), KH2 PO4 (2.64 g/L), Na2 HPO4 ·12H2 O (12 g/L), MgSO4 ·7H2 O (0.5 g/L), and CaCl2 ·2H2 O (5 mg/L). The yield of 3-hydroxycarboxylic acid obtained using the optimized culture medium was 56.8 ± 1.64%, which was 2.5-fold higher than that obtained when the unoptimized culture medium was used.
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Affiliation(s)
- Zhanyong Wang
- College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun, People's Republic of China
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