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Chandramouli Swamy TM, Nagarathna SV, Reddy PV, Nayak AS. Efficient biodegradation of Polyethylene terephthalate (PET) plastic by Gordonia sp. CN2K isolated from plastic contaminated environment. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 281:116635. [PMID: 38944007 DOI: 10.1016/j.ecoenv.2024.116635] [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: 01/15/2024] [Revised: 06/16/2024] [Accepted: 06/21/2024] [Indexed: 07/01/2024]
Abstract
Since we rely entirely on plastics or their products in our daily lives, plastics are the invention of the hour. Polyester plastics, such as Polyethylene Terephthalate (PET), are among the most often used types of plastics. PET plastics have a high ratio of aromatic components, which makes them very resistant to microbial attack and highly persistent. As a result, massive amounts of plastic trash accumulate in the environment, where they eventually transform into microplastic (<5 mm). Rather than macroplastics, microplastics are starting to pose a serious hazard to the environment. It is imperative that these polymer microplastics be broken down. Through the use of enrichment culture, the PET microplastic-degrading bacterium was isolated from solid waste management yards. Bacterial strain was identified as Gordonia sp. CN2K by 16 S rDNA sequence analysis and biochemical characterization. It is able to use polyethylene terephthalate as its only energy and carbon source. In 45 days, 40.43 % of the PET microplastic was degraded. By using mass spectral analysis and HPLC to characterize the metabolites produced during PET breakdown, the degradation of PET is verified. The metabolites identified in the spent medium included dimer compound, bis (2-hydroxyethyl) terephthalate (BHET), mono (2-hydroxyethyl) terephthalate (MHET), and terephthalate. Furthermore, the PET sheet exposed to the culture showed considerable surface alterations in the scanning electron microscope images. This illustrates how new the current work is.
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Affiliation(s)
| | - S V Nagarathna
- Department of Biochemistry, Gulbarga University, Kalaburagi, Karnataka 585106, India
| | - Pooja V Reddy
- Department of Biochemistry, Gulbarga University, Kalaburagi, Karnataka 585106, India
| | - Anand S Nayak
- Department of Biochemistry, Gulbarga University, Kalaburagi, Karnataka 585106, India.
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2
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Liu X, Zhou M, Sun R, Xing S, Wu T, He H, Chen J, Bielicki JK. Characterization of a Novel Esterase Est33 From an Antarctic Bacterium: A Representative of a New Esterase Family. Front Microbiol 2022; 13:855658. [PMID: 35655995 PMCID: PMC9152352 DOI: 10.3389/fmicb.2022.855658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 04/18/2022] [Indexed: 11/26/2022] Open
Abstract
Studies of microorganisms from extreme environments can sometimes reveal novel proteins with unique properties. Here, we identified a novel esterase gene (Est33) from an Antarctic bacterium. The protein was expressed and purified for biochemical characterizations. Site-mutation variants including S94A, D205A, and H233A were constructed to explore the structure–function relationship of the catalytic triad of Est33, and we found mutating Ser94, Asp205, and His233 residues lead to a complete loss of enzyme activity. In addition, the catalytic Ser94 located in a conserved pentapeptide motif GVSWG. Phylogenetic analysis showed that Est33 and its closely related homologs belonged to an independent group apart from other known family members, indicating that Est33 represented a new family of esterase. The Est33 enzyme was found to be a cold-active esterase retaining 25%–100% activity from 10°C to 30°C and to have optimal catalytic activity toward p-nitrophenol acetate (30°C and pH7.5). The serine modifying reagent phenylmethylsulfonyl fluoride inhibited the activity of Est33 by 77.34%, while thiol reagents such as dithiol threitol (DTT) activated the enzyme by 3-fold. Metal chelating reagents EDTA had no effects, indicating that Est33 is not a metalloenzyme. Collectively, these results indicate that Est33 constitutes the first member of a novel esterase family XXI that has been identified.
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Affiliation(s)
- Xiaoyu Liu
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Mingyang Zhou
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Rui Sun
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Shu Xing
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Tao Wu
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Hailun He
- State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Jianbin Chen
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China.,Shandong Provincial Key Laboratory of Molecular Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - John Kevin Bielicki
- Lawrence Berkeley National Laboratory, University of California at Berkeley, Berkeley, CA, United States
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Noby N, Hussein A, Saeed H, Embaby AM. "Recombinant cold -adapted halotolerant, organic solvent-stable esterase (estHIJ) from Bacillus halodurans. Anal Biochem 2019; 591:113554. [PMID: 31863727 DOI: 10.1016/j.ab.2019.113554] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/08/2019] [Accepted: 12/17/2019] [Indexed: 12/12/2022]
Abstract
Esterases and lipases enduring harsh conditions, including low temperature and extreme tolerance to organic solvents, have attracted great attention in recent times. In the current study, a full open reading frame of 747 bp that encodes a novel, cold-adapted esterase (estHIJ) of 248 amino acids from Bacillus halodurans strain NAH-Egypt was heterologously cloned and expressed in E. coli BL21 (DE3) Rosetta. Amino acid sequence analysis revealed that estHIJ belongs to family XIII of lipolytic enzymes, with a characteristic pentapeptide motif (G-L-S-L-G). The recombinant estHIJ was purified using Ni-affinity chromatography to homogeneity with purification fold, yield, specific activity, and molecular weight (MW) of 3.5, 47.5%, 19.8 U/mg and 29 kDa, respectively. The enzyme showed preferential substrate specificity towards pNP-acetate (C2), with catalytic efficiency of 46,825 min-1 mM-1 estHIJ displayed optimal activity at 30 °C and pH (7.0-8.0). estHIJ demonstrated robust stability in the presence of 50% (v/v) non-polar solvents and 4 M NaCl after 15 h and 6 h of incubation, respectively. The promising features of the recombinant estHIJ underpin its potential in several fields, e.g., the synthesis of pharmaceutical compounds and the food industry.
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Affiliation(s)
- Nehad Noby
- Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, Alexandria, Egypt
| | - Ahmed Hussein
- Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, Alexandria, Egypt
| | - Hesham Saeed
- Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, Alexandria, Egypt
| | - Amira M Embaby
- Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, Alexandria, Egypt.
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4
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Munar MP, Takahashi H, Okamura Y. Discovery of a Novel Gene Conferring Tellurite Tolerance Through Tellurite Reduction to Escherichia coli Transformant in Marine Sediment Metagenomic Library. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2019; 21:762-772. [PMID: 31637558 DOI: 10.1007/s10126-019-09922-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 09/02/2019] [Indexed: 06/10/2023]
Abstract
Metagenomic library construction using a marine sediment-enrichment was employed in order to recover tellurium from tellurite, a tellurium oxyanion, dissolved in water and then functional screening was performed to discover a novel gene related to tellurite reduction. Transmission electron microscopy (TEM) revealed the formation of intracellular Te crystals in Escherichia coli cells transformed with a specific DNA fragment from the marine sediment metagenome. The metagenome fragment was composed of 691 bp and showed low homology to known proteins. Phylogenetic analysis suggested that the metagenome fragment was related to Pseudomonas stutzeri. Cloning and expression of an open reading frame (ORF) on the metagenome fragment validated the role of the fragment in conferring tellurite resistance and tellurite-reducing activity to E. coli host cells. E. coli transformant containing the ORF1 showed resistance to 1 mM Na2TeO3. The optimal tellurite-reducing activity of cells containing the ORF1 was recorded at 37 °C and pH 7.0.
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Affiliation(s)
- Madison Pascual Munar
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Hiroshima, Japan
| | - Hirokazu Takahashi
- Unit of Biotechnology, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Yoshiko Okamura
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Hiroshima, Japan.
- Unit of Biotechnology, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan.
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Nguyen SN, Flores A, Talamantes D, Dar F, Valdez A, Schwans J, Berlemont R. GeneHunt for rapid domain-specific annotation of glycoside hydrolases. Sci Rep 2019; 9:10137. [PMID: 31300677 PMCID: PMC6626019 DOI: 10.1038/s41598-019-46290-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 06/26/2019] [Indexed: 12/20/2022] Open
Abstract
The identification of glycoside hydrolases (GHs) for efficient polysaccharide deconstruction is essential for the development of biofuels. Here, we investigate the potential of sequential HMM-profile identification for the rapid and precise identification of the multi-domain architecture of GHs from various datasets. First, as a validation, we successfully reannotated >98% of the biochemically characterized enzymes listed on the CAZy database. Next, we analyzed the 43 million non-redundant sequences from the M5nr data and identified 322,068 unique GHs. Finally, we searched 129 assembled metagenomes retrieved from MG-RAST for environmental GHs and identified 160,790 additional enzymes. Although most identified sequences corresponded to single domain enzymes, many contained several domains, including known accessory domains and some domains never identified in association with GH. Several sequences displayed multiple catalytic domains and few of these potential multi-activity proteins combined potentially synergistic domains. Finally, we produced and confirmed the biochemical activities of a GH5-GH10 cellulase-xylanase and a GH11-CE4 xylanase-esterase. Globally, this "gene to enzyme pipeline" provides a rationale for mining large datasets in order to identify new catalysts combining unique properties for the efficient deconstruction of polysaccharides.
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Affiliation(s)
- S N Nguyen
- Department of Biological Sciences, California State University Long Beach, Long Beach, California, USA
| | - A Flores
- Department of Biological Sciences, California State University Long Beach, Long Beach, California, USA
| | - D Talamantes
- Department of Biological Sciences, California State University Long Beach, Long Beach, California, USA
| | - F Dar
- Department of Biological Sciences, California State University Long Beach, Long Beach, California, USA
| | - A Valdez
- Department of Biological Sciences, California State University Long Beach, Long Beach, California, USA
| | - J Schwans
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, California, USA
| | - R Berlemont
- Department of Biological Sciences, California State University Long Beach, Long Beach, California, USA.
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Chrismas NAM, Anesio AM, Sánchez-Baracaldo P. The future of genomics in polar and alpine cyanobacteria. FEMS Microbiol Ecol 2018; 94:4904125. [PMID: 29506259 PMCID: PMC5939894 DOI: 10.1093/femsec/fiy032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 02/23/2018] [Indexed: 01/01/2023] Open
Abstract
In recent years, genomic analyses have arisen as an exciting way of investigating the functional capacity and environmental adaptations of numerous micro-organisms of global relevance, including cyanobacteria. In the extreme cold of Arctic, Antarctic and alpine environments, cyanobacteria are of fundamental ecological importance as primary producers and ecosystem engineers. While their role in biogeochemical cycles is well appreciated, little is known about the genomic makeup of polar and alpine cyanobacteria. In this article, we present ways that genomic techniques might be used to further our understanding of cyanobacteria in cold environments in terms of their evolution and ecology. Existing examples from other environments (e.g. marine/hot springs) are used to discuss how methods developed there might be used to investigate specific questions in the cryosphere. Phylogenomics, comparative genomics and population genomics are identified as methods for understanding the evolution and biogeography of polar and alpine cyanobacteria. Transcriptomics will allow us to investigate gene expression under extreme environmental conditions, and metagenomics can be used to complement tradition amplicon-based methods of community profiling. Finally, new techniques such as single cell genomics and metagenome assembled genomes will also help to expand our understanding of polar and alpine cyanobacteria that cannot readily be cultured.
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Affiliation(s)
- Nathan A M Chrismas
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS, UK
- Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Alexandre M Anesio
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS, UK
| | - Patricia Sánchez-Baracaldo
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS, UK
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Gao H, Li C, Bandikari R, Liu Z, Hu N, Yong Q. A novel cold-adapted esterase from Enterobacter cloacae: Characterization and improvement of its activity and thermostability via the site of Tyr193Cys. Microb Cell Fact 2018; 17:45. [PMID: 29554914 PMCID: PMC5858142 DOI: 10.1186/s12934-018-0885-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 02/26/2018] [Indexed: 11/10/2022] Open
Abstract
Background In industries lipolytic reactions occur in insensitive conditions such as high temperature thus novel stout esterases with unique properties are attracts to the industrial application. Protein engineering is the tool to obtain desirable characters of enzymes. A novel esterase gene was isolated from South China Sea and subjected to a random mutagenesis and site directed mutagenesis for higher activity and thermo-stability compared to wild type. Results A novel esterase showed the highest hydrolytic activity against p-nitrophenyl acetate (pNPA, C2) and the optimal activity at 40 °C and pH 8.5. It was a cold-adapted enzyme and retained approximately 40% of its maximum activity at 0 °C. A mutant, with higher activity and thermo-stability was obtained by random mutagenesis. Kinetic analysis indicated that the mutant Val29Ala/Tyr193Cys shown 43.5% decrease in Km, 2.6-fold increase in Kcat, and 4.7-fold increase in Kcat/Km relative to the wild type. Single mutants V29A and Y193C were constructed and their kinetic parameters were measured. The results showed that the values of Km, Kcat, and Kcat/Km of V29A were similar to those of the wild type while Y193C showed 52.7% decrease in Km, 2.7-fold increase in Kcat, and 5.6-fold increase in Kcat/Km compared with the wild type. The 3-D structure and docking analysis revealed that the replacement of Tyr by Cys could enlarge the binding pocket. Moreover Y193C also showed a better thermo-stability for the reason its higher hydrophobicity and retained 67% relative activity after incubation for 3 h at 50 °C. Conclusions The superior quality of modified esterase suggested it has great potential application in extreme conditions and the mutational work recommended that important information for the study of esterase structure and function. Electronic supplementary material The online version of this article (10.1186/s12934-018-0885-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Haofeng Gao
- College of Light Industry Science and Engineering, Nanjing Forestry University, 159 Longpan Road, Nanjing, 210018, China.,College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30 Puzhu South Road, Nanjing, 211800, China
| | - Chanjuan Li
- College of Life Science and Technology, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ramesh Bandikari
- College of Life Science and Technology, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ziduo Liu
- College of Life Science and Technology, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Nan Hu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30 Puzhu South Road, Nanjing, 211800, China.
| | - Qiang Yong
- College of Light Industry Science and Engineering, Nanjing Forestry University, 159 Longpan Road, Nanjing, 210018, China.
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Baeza M, Barahona S, Alcaíno J, Cifuentes V. Amplicon-Metagenomic Analysis of Fungi from Antarctic Terrestrial Habitats. Front Microbiol 2017; 8:2235. [PMID: 29184546 PMCID: PMC5694453 DOI: 10.3389/fmicb.2017.02235] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 10/31/2017] [Indexed: 01/08/2023] Open
Abstract
In cold environments such as polar regions, microorganisms play important ecological roles, and most of our knowledge about them comes from studies of cultivable microorganisms. Metagenomic technologies are powerful tools that can give a more comprehensive assessment of microbial communities, and the amplification of rDNA followed by next-generation sequencing has given good results in studies aimed particularly at environmental microorganisms. Culture-independent studies of microbiota in terrestrial habitats of Antarctica, which is considered the driest, coldest climate on Earth, are increasing and indicate that micro-diversity is much higher than previously thought. In this work, the microbial diversity of terrestrial habitats including eight islands of the South Shetland Archipelago, two islands on the Antarctic Peninsula and Union Glacier, was studied by amplicon-metagenome analysis. Molecular analysis of the studied localities clustered together the islands of the South Shetland Archipelago, except Greenwich Island, and separated them from the Litchfield and Lagotellerie islands and Union Glacier, which is in agreement with the latitudinal difference among them. Among fungi, 87 genera and 123 species were found, of which species belonging to 37 fungal genera not previously cultivated from Antarctica were detected. Phylogenetic analysis, including the closest BLAST-hit sequences, clustered fungi in 11 classes being the most represented Lecanoromycetes and Eurotiomycetes.
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Affiliation(s)
- Marcelo Baeza
- Laboratorio de Genética, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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Hang Y, Ran S, Wang X, Jiao J, Wang S, Liu Z. Mutational analysis and stability characterization of a novel esterase of lipolytic enzyme family VI from Shewanella sp. Int J Biol Macromol 2016; 93:655-664. [PMID: 27632949 DOI: 10.1016/j.ijbiomac.2016.09.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 08/19/2016] [Accepted: 09/11/2016] [Indexed: 11/17/2022]
Abstract
Esterases are widely used in different industries. Here, a novel esterase, Esth, with low identity with previously reported esterases, was identified and characterized. The results showed that Esth was a cold-adapted esterase and retained 50% of its maximum activity at 0°C. Besides, Esth showed great activity and stability in high concentrations of NaCl. When treated with some organic solvents, detergents and metal ions, Esth showed high activity as well. The kcat/Km value of Esth was 29.5s-1mM-1, suggesting that it has higher catalytic efficiency than all the previously reported esterases from the same family, lipolytic enzyme family VI. The structural modeling showed that changing Ala129 into Gly would form a new hydrogen bond between ser125 and Gly129 and make theα-helix longer, which might influence on the thermostability of enzymes (Kumar, 2000). To confirm this, the mutant EsthA129G was obtained by site-directed mutagenesis. The result indicated that EsthA129G retained over 70% of the activity versus 12% for Esth after incubation at 55°C for 120min, showed a nearly six fold increase when compared with wild type. Overall, Esth shows a potential application prospect in extreme conditions and the mutation research can provide some structural information about thermostable enzymes.
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Affiliation(s)
- Yian Hang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Shi Ran
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Xiangyu Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Jingwen Jiao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Shunyao Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Ziduo Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
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Characterization of a novel cold active and salt tolerant esterase from Zunongwangia profunda. Enzyme Microb Technol 2016; 85:1-11. [DOI: 10.1016/j.enzmictec.2015.12.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 12/18/2015] [Accepted: 12/29/2015] [Indexed: 01/13/2023]
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De Santi C, Altermark B, Pierechod MM, Ambrosino L, de Pascale D, Willassen NP. Characterization of a cold-active and salt tolerant esterase identified by functional screening of Arctic metagenomic libraries. BMC BIOCHEMISTRY 2016; 17:1. [PMID: 26782782 PMCID: PMC4717575 DOI: 10.1186/s12858-016-0057-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 01/14/2016] [Indexed: 12/26/2022]
Abstract
BACKGROUND The use of metagenomics in enzyme discovery constitutes a powerful approach to access to genomes of unculturable community of microorganisms and isolate novel valuable biocatalysts for use in a wide range of biotechnological and pharmaceutical fields. RESULTS Here we present a novel esterase gene (lip3) identified by functional screening of three fosmid metagenomic libraries, constructed from three marine sediment samples. The sequenced positive fosmid revealed an enzyme of 281 amino acids with similarity to class 3 lipases. The 3D modeling of Lip3 was generated by homology modeling on the basis of four lipases templates [PDB ID: 3O0D, 3NGM, 3G7N, 2QUB] to unravel structural features of this novel enzyme. The catalytic triad of Lip3 was predicted to be Asp207, His267 and the catalytic nucleophile Ser150 in a conserved pentapeptide (GXSXG). The 3D model highlighted the presence of a one-helix lid able to regulate the access of the substrate to the active site when the enzyme binds a hydrophobic interface. Moreover an analysis of the external surface of Lip3 model showed that the majority of the surface regions were hydrophobic (59.6 %) compared with homologous lipases (around 35 %) used as templates. The recombinant Lip3 esterase, expressed and purified from Escherichia coli, preferentially hydrolyzed short and medium length p-nitrophenyl esters with the best substrate being p-nitrophenyl acetate. Further characterization revealed a temperature optimum of 35 °C and a pH optimum of 8.0. Lip3 exhibits a broad temperature stability range and tolerates the presence of DTT, EDTA, PMSF, β-mercaptoethanol and high concentrations of salt. The enzyme was also highly activated by NaCl. CONCLUSIONS The biochemical characterization and homology model reveals a novel esterase originating from the marine Arctic metagenomics libraries with features of a cold-active, relatively thermostable and highly halotolerant enzyme. Taken together, these results suggest that this esterase could be a highly valuable candidate for biotechnological applications such as organic synthesis reactions and cheese ripening processes.
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Affiliation(s)
- Concetta De Santi
- NorStruct, Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, Tromsø, Norway.
| | - Bjørn Altermark
- NorStruct, Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, Tromsø, Norway.
| | - Marcin Miroslaw Pierechod
- NorStruct, Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, Tromsø, Norway.
| | - Luca Ambrosino
- Institute of Protein Biochemistry, National Research Council, Naples, Italy.
| | | | - Nils-Peder Willassen
- NorStruct, Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, Tromsø, Norway.
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Mishra S, Singh SN, Pande V. Bacteria induced degradation of fluoranthene in minimal salt medium mediated by catabolic enzymes in vitro condition. BIORESOURCE TECHNOLOGY 2014; 164:299-308. [PMID: 24862007 DOI: 10.1016/j.biortech.2014.04.076] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 04/17/2014] [Accepted: 04/21/2014] [Indexed: 06/03/2023]
Abstract
Fluoranthene is highly toxic and ubiquitous in the environment. A study on degradation of 200 ppm of fluoranthene in MSM by two bacterial strains Pseudomonas aeruginosa PSA5, Rhodococcus sp. NJ2 and their consortium revealed that fluoranthene was degraded 74% by Rhodococcus sp. NJ2, 61% by Pseudomonas sp. PSA5 and 97% by their consortium. Higher degradation in the consortium may be attributed to synergistic action between two bacteria. It was also observed that several degradative enzymes catechol 1,2 dioxygenase, catechol 2,3 dioxygenase, protocatechuate 2,3 dioxygenase, protocatechuate 3,4 dioxygenase, protocatechuate 4,5 dioxygenase, salicylate hydroxylase and 2-carboxybenzaldehyde dehydrogenase were differentially induced at different stages of fluoranthene degradation. Biodegradation kinetics indicated half life period of fluoranthene degradation. Besides, glycolipid, as a biosurfactant, was induced to facilitate the degradation process. Hence, both the bacteria may be used individually or in combination for effective decontamination of oil and sludge contaminated soil.
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Affiliation(s)
- Shweta Mishra
- Environmental Science Division, CSIR-National Botanical Research Institute (NBRI), Lucknow, Uttar Pradesh, India
| | - S N Singh
- Environmental Science Division, CSIR-National Botanical Research Institute (NBRI), Lucknow, Uttar Pradesh, India.
| | - Veena Pande
- Department of Biotechnology, Kumaun University Nainital, Uttarakhand, India
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Pranaw K, Singh S, Dutta D, Chaudhury S, Ganguly S, Nain L. Biodegradation of dimethyl phthalate by an entomopathogenic nematode symbiont Xenorhabdus indica strain KB-3. INTERNATIONAL BIODETERIORATION & BIODEGRADATION 2014; 89:23-28. [DOI: 10.1016/j.ibiod.2014.01.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
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