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Demir Öksüz Z, Doruk T, Yağci N, Tunca Gedik S. Polyhydroxyalkanoate accumulation in Streptomyces coelicolor affected by SCO7613 gene region. ACTA ACUST UNITED AC 2021; 45:275-286. [PMID: 34377052 PMCID: PMC8313934 DOI: 10.3906/biy-2011-16] [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: 11/06/2020] [Accepted: 04/20/2021] [Indexed: 11/03/2022]
Abstract
Polyhydroxyalkanoate (PHA) is stored as an important carbon and energy source in bacterial cells. For biomedical applications, gram-positive bacteria can be better sources of PHAs, since they lack outer membrane lipopolysaccharide. Although gram-positive Streptomyces coelicolor A3(2) has been indicated as a high potential PHA producer, pha C gene that encodes the key enzyme PHA synthase in the metabolic pathway is not determined in its genome. BLAST search results of the GenBank database argued that SCO7613 could specify a putative polyhydroxyalkanoate synthase (PhaC) responsible for PHA biosynthesis. Deduced amino acid sequence of SCO7613 showed the presence of conserved lipase box like sequence, 555GASAG559, in which serine residue was present as the active nucleophile. Present study describes deletion of putative S. coelicolor pha C gene via PCR dependent method. We showed that SCO7613 is not an essential gene in S. coelicolor and its deletion affected PHA accumulation negatively although it is not ceased. Transcomplementation abolished the mutant phenotype, demonstrating that the decrease in PHA resulted from the deletion of SCO7613.
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Affiliation(s)
- Zeynep Demir Öksüz
- Molecular Biology and Genetic Department, Faculty of Science, Gebze Technical University, Kocaeli Turkey
| | - Tuğrul Doruk
- Molecular Biology and Genetic Department, Faculty of Science, Gebze Technical University, Kocaeli Turkey.,Molecular Biology and Genetic Department, Faculty of Arts and Science, Ondokuz Mayıs University, Samsun Turkey
| | - Nevin Yağci
- Department of Environmental Engineering, Faculty of Civil Engineering, İstanbul Technical University, İstanbul Turkey
| | - Sedef Tunca Gedik
- Molecular Biology and Genetic Department, Faculty of Science, Gebze Technical University, Kocaeli Turkey
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2
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Amadu AA, Qiu S, Ge S, Addico GND, Ameka GK, Yu Z, Xia W, Abbew AW, Shao D, Champagne P, Wang S. A review of biopolymer (Poly-β-hydroxybutyrate) synthesis in microbes cultivated on wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 756:143729. [PMID: 33310224 DOI: 10.1016/j.scitotenv.2020.143729] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 06/12/2023]
Abstract
The large quantities of non-degradable single use plastics, production and disposal, in addition to increasing amounts of municipal and industrial wastewaters are among the major global issues known today. Biodegradable plastics from biopolymers such as Poly-β-hydroxybutyrates (PHB) produced by microorganisms are potential substitutes for non-degradable petroleum-based plastics. This paper reviews the current status of wastewater-cultivated microbes utilized in PHB production, including the various types of wastewaters suitable for either pure or mixed culture PHB production. PHB-producing strains that have the potential for commercialization are also highlighted with proposed selection criteria for choosing the appropriate PHB microbe for optimization of processes. The biosynthetic pathways involved in producing microbial PHB are also discussed to highlight the advancements in genetic engineering techniques. Additionally, the paper outlines the factors influencing PHB production while exploring other metabolic pathways and metabolites simultaneously produced along with PHB in a bio-refinery context. Furthermore, the paper explores the effects of extraction methods on PHB yield and quality to ultimately facilitate the commercial production of biodegradable plastics. This review uniquely discusses the developments in research on microbial biopolymers, specifically PHB and also gives an overview of current commercial PHB companies making strides in cutting down plastic pollution and greenhouse gases.
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Affiliation(s)
- Ayesha Algade Amadu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Shuang Qiu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Shijian Ge
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China.
| | - Gloria Naa Dzama Addico
- Council for Scientific and Industrial Research (CSIR) - Water Research Institute (WRI), P.O. Box AH 38, Achimota Greater Accra, Ghana
| | - Gabriel Komla Ameka
- Department of Botany, University of Ghana, P.O. Box LG55, Legon, Accra, Ghana
| | - Ziwei Yu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Wenhao Xia
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Abdul-Wahab Abbew
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Dadong Shao
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Pascale Champagne
- Department of Civil Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Sufeng Wang
- School of Economics and Management, Anhui Jianzhu University, Hefei, Anhui 230601, PR China
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Porras MA, Ramos FD, Diaz MS, Cubitto MA, Villar MA. Modeling the bioconversion of starch to P(HB-co-HV) optimized by experimental design using Bacillus megaterium BBST4 strain. ENVIRONMENTAL TECHNOLOGY 2019; 40:1185-1202. [PMID: 29243993 DOI: 10.1080/09593330.2017.1418436] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 12/13/2017] [Indexed: 06/07/2023]
Abstract
Poly(hydroxybutyrate-co-hydroxyvalerate) (P(HB-co-HV)) is a prominent biopolymer as a potential candidate for use in the biomedical area. Several Bacillus spp. strains show promising characteristics in the use of several carbon sources and are an interesting alternative for the production of P(HB-co-HV). Sewage from the agricultural and food processing industries can be used to obtain abundantly starch as a carbon source for PHA production. The aim of the present study was to optimize by response surface methodology and desirability, the production of PHA by a Bacillus megaterium strain using starch as the sole carbon source. Two optimal conditions were determined without sporulation and were used to perform new experiments to calibrate and validate a mechanistic model, developed to simulate the dynamics of PHA and biomass production. The developed model successfully represents the kinetics of the microorganism. Employing different characterization techniques, it was determined that the PHA produced by the strain is a copolymer composed of different HB:HV proportions. Using starch as the sole carbon source in a minimal salt medium, this work shows the first reports in the literature of: 1) a mathematical model for predicting growth kinetic and PHA production for B. megaterium strain and 2) a Bacillus spp. producing P(HB-co-HV) copolymer.
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Affiliation(s)
- Mauricio A Porras
- a Departamento de Biología, Bioquímica y Farmacia , Universidad Nacional del Sur , Bahía Blanca , Argentina
- b Planta Piloto de Ingeniería Química, PLAPIQUI (UNS-CONICET) , Bahía Blanca , Argentina
| | - Fernando D Ramos
- b Planta Piloto de Ingeniería Química, PLAPIQUI (UNS-CONICET) , Bahía Blanca , Argentina
- c Departamento de Ingeniería Química , Universidad Nacional del Sur , Bahía Blanca , Argentina
| | - María S Diaz
- b Planta Piloto de Ingeniería Química, PLAPIQUI (UNS-CONICET) , Bahía Blanca , Argentina
- c Departamento de Ingeniería Química , Universidad Nacional del Sur , Bahía Blanca , Argentina
| | - María A Cubitto
- a Departamento de Biología, Bioquímica y Farmacia , Universidad Nacional del Sur , Bahía Blanca , Argentina
- d Centro de Recursos Naturales Renovables de la Zona Semiárida, CERZOS (UNS-CONICET) , Bahía Blanca , Argentina
| | - Marcelo A Villar
- b Planta Piloto de Ingeniería Química, PLAPIQUI (UNS-CONICET) , Bahía Blanca , Argentina
- c Departamento de Ingeniería Química , Universidad Nacional del Sur , Bahía Blanca , Argentina
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Elsayed NS, Aboshanab KM, Yassien MA, Hassouna NA. Kinetic modeling, recovery, and molecular characterization of poly-beta-hydroxybutyrate polymer in Acinetobacter baumannii isolate P39. Bioprocess Biosyst Eng 2018; 41:1779-1791. [PMID: 30194493 DOI: 10.1007/s00449-018-2000-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 08/10/2018] [Indexed: 11/26/2022]
Abstract
To control the poly-β-hydroxybutyrate (PHB) biopolymer production by Acinetobacter baumannii isolate P39 kinetic modeling of the fermentation process, polymer downstream processing, enzymological analysis, and molecular characterization of PHA synthase, key biosynthetic enzyme, should be addressed. A. baumannii isolate P39 produced 0.15 g/L PHB after 24 h of incubation with a polymer content of 28% per dry weight. Logistic and Leudeking-Piret models were used for describing cell growth and PHB production, respectively. They showed good agreement with the experimental data describing both cell growth and PHB production (average regression coefficient r2:0.999). The growth-associated production of PHB biopolymer as an electron acceptor was confirmed using Leudeking-Piret model and victim substrate experiment. The best method of recovery of PHB biopolymer was chemical digestion using sodium hypochlorite, since it produced the largest amount of polymer and highest molecular weight (16,000 g/mole) in comparison to other recovery methods. DTNB assay showed high activity of PHA synthase enzyme, 600 U activity, and 153.8 U/mg specific activity. Molecular analysis of PHA synthase enzyme confirmed class III identity. Taken together, micelle model was proposed for polyhydroxybutyrate formation in A. baumannii isolate P39.
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Affiliation(s)
- Noha S Elsayed
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, Organization of African Unity St, Abbassia, P.O. Box 11566, Cairo, Egypt
| | - Khaled M Aboshanab
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, Organization of African Unity St, Abbassia, P.O. Box 11566, Cairo, Egypt
| | - Mahmoud A Yassien
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, Organization of African Unity St, Abbassia, P.O. Box 11566, Cairo, Egypt.
| | - Nadia A Hassouna
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, Organization of African Unity St, Abbassia, P.O. Box 11566, Cairo, Egypt
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Kavitha G, Rengasamy R, Inbakandan D. Polyhydroxybutyrate production from marine source and its application. Int J Biol Macromol 2018; 111:102-108. [DOI: 10.1016/j.ijbiomac.2017.12.155] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 10/18/2017] [Accepted: 12/28/2017] [Indexed: 11/17/2022]
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Biotechnological Production of Polyhydroxyalkanoates: A Review on Trends and Latest Developments. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/802984] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Polyhydroxyalkanoates (PHA) producers have been reported to reside at various ecological niches which are naturally or accidently exposed to high organic matter or growth limited conditions such as dairy wastes, hydrocarbon contaminated sites, pulp and paper mill wastes, agricultural wastes, activated sludges of treatment plants, rhizosphere, and industrial effluents. Few among them also produce extracellular by-products like rhamnolipids, extracellular polymeric substances, and biohydrogen gas. These sorts of microbes are industrially important candidates for the reason that they can use waste materials of different origin as substrate with simultaneous production of valuable bioproducts including PHA. Implementation of integrated system to separate their by-products (intracellular and extracellular) can be economical in regard to production. In this review, we have discussed various microorganisms dwelling at different environmental conditions which stimulate them to accumulate carbon as polyhydroxyalkanoates granules and factors influencing its production and composition. A brief aspect on metabolites which are produced concomitantly with PHA has also been discussed. In conclusion, exploring of capabilities like of dual production by microbes and use of wastes as renewable substrate under optimized cultural conditions either in batch or continuous process can cause deduction in present cost of bioplastic production from stored PHA granules.
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Saranya S, Radha KV. Preparation and characterization of native poly(3-hydroxybutyrate) microspheres from Bacillus subtilis MTCC 9763. J BIOACT COMPAT POL 2014. [DOI: 10.1177/0883911513520380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Poly(3-hydroxybutyrate) is a biodegradable and biocompatible polymer with many potential biomedical applications including medical implants and drug delivery systems. In this study, poly(3-hydroxybutyrate) production by Bacillus subtilis MTCC 9763 was optimized for different physical and chemical parameters. A 90% poly(3-hydroxybutyrate) accumulation was achieved with 2% fructose and 0.5% ammonium sulfate as carbon and nitrogen sources. The effective accumulation occurred at pH 7. The poly(3-hydroxybutyrate) content of dry cell weight increased to 87% at 36 h of incubation. The synthesized poly(3-hydroxybutyrate) was characterized by Fourier transform infrared and nuclear magnetic resonance spectroscopies. The oil-in-water solvent evaporation technique was used to fabricate the poly(3-hydroxybutyrate) microspheres. The surface morphology appeared smooth in the range of 1–2 µm with specific surface area ranging 19 to 20 m2/g. The synthesized poly(3-hydroxybutyrate) microspheres were nontoxic and exhibited good cytocompatibility toward NIH 3T3 fibroblasts.
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Affiliation(s)
- S Saranya
- Department of Chemical Engineering, A.C. Tech, Anna University, Chennai, India
| | - KV Radha
- Department of Chemical Engineering, A.C. Tech, Anna University, Chennai, India
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Characterization of medium chain length (R)-3-hydroxycarboxylic acids produced by Streptomyces sp. JM3 and the evaluation of their antimicrobial properties. World J Microbiol Biotechnol 2012; 28:2791-800. [DOI: 10.1007/s11274-012-1089-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Accepted: 05/22/2012] [Indexed: 11/27/2022]
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9
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Biosynthesis of PHB from a new isolated Bacillus megaterium strain: Outlook on future developments with endospore forming bacteria. BIOTECHNOL BIOPROC E 2012. [DOI: 10.1007/s12257-011-0448-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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10
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Matias F, Bonatto D, Padilla G, Rodrigues MFDA, Henriques JAP. Polyhydroxyalkanoates production by actinobacteria isolated from soil. Can J Microbiol 2009; 55:790-800. [PMID: 19767851 DOI: 10.1139/w09-029] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Polyhydroxyalkanoates (PHAs) are biodegradable and renewable polymers produced by a wide range of bacterial groups. New microbial bioprospection approaches have become an important way to find new PHA producers and new synthesized polymers. Over the past years, bacteria belonging to actinomycetes group have become known as PHA producers, such as Nocardia and Rhodococcus species, Kineosphaera limosa Liu et al. 2002, and, more recently, Streptomyces species. In this paper, we disclose that there are more actinobacteria PHA producers in addition to the genera cited. Some unusual genera, such as Streptoalloteichus, and some genera frequently present in soil, such as Streptacidiphilus, have been found. Thirty-four isolates were able to accumulate poly(3-hydroxybutyrate) and a number of these have traces of poly(3-hydroxyvalerate) when cultivated on glucose or glucose and casein as carbon source. Furthermore, some strains showed traces of medium chain length PHA. Transmission electron microscopy demonstrated that the PHA accumulation occurs in hyphae and spores.
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Affiliation(s)
- Fernanda Matias
- Universidade de São Paulo, Instituto de Ciências Biomédicas II, Av. Professor Lineu Prestes, 1374 São Paulo, São Paulo 05508-900, Brazil
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11
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Valappil SP, Peiris D, Langley GJ, Herniman JM, Boccaccini AR, Bucke C, Roy I. Polyhydroxyalkanoate (PHA) biosynthesis from structurally unrelated carbon sources by a newly characterized Bacillus spp. J Biotechnol 2007; 127:475-87. [PMID: 16956686 DOI: 10.1016/j.jbiotec.2006.07.015] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 07/14/2006] [Accepted: 07/20/2006] [Indexed: 11/20/2022]
Abstract
A newly acquired polyhydroxyalkanoate (PHA) producing Bacillus spp. was identified to be a strain of Bacillus cereus using a range of microbiological and molecular techniques. This strain, named B. cereus SPV, was found to be capable of using a wide range of carbon sources including glucose, fructose, sucrose, various fatty acids and gluconate for the production of PHAs, an advantage for the commercial production of the polymers. The media used for the polymer production was novel in the context of the genus Bacillus. The PHA, once produced, was found to remain at a constant maximal concentration, without any degradation, a great advantage for the commercial production of the PHAs. This particular strain of Bacillus spp. was able to synthesize various PHAs with 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV) and 4-hydroxybutyrate (4HB)-like monomer units from structurally unrelated carbon sources such as fructose, sucrose and gluconate. This is the first report of the incorporation of a 4HB related monomer containing PHA by the genus Bacillus and from structurally unrelated carbon sources. The PHAs isolated had molecular weights ranging between (0.4 and 0.8) x 10(6) and low polydispersity index values (M(W)/M(N)) ranging from 2.6 to 3.4.
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Affiliation(s)
- S P Valappil
- Department of Molecular and Applied Biosciences, School of Biosciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK
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Valappil SP, Boccaccini AR, Bucke C, Roy I. Polyhydroxyalkanoates in Gram-positive bacteria: insights from the genera Bacillus and Streptomyces. Antonie van Leeuwenhoek 2006; 91:1-17. [PMID: 17016742 DOI: 10.1007/s10482-006-9095-5] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Accepted: 05/23/2006] [Indexed: 10/24/2022]
Abstract
Gram-positive bacteria, notably Bacillus and Streptomyces, have been used extensively in industry. However, these microorganisms have not yet been exploited for the production of the biodegradable polymers, polyhydroxyalkanoates (PHAs). Although PHAs have many potential applications, the cost of production means that medical applications are currently the main area of use. Gram-negative bacteria, currently the only commercial source of PHAs, have lipopolysaccharides (LPS) which co-purify with the PHAs and cause immunogenic reactions. On the other hand, Gram- positive bacteria lack LPS, a positive feature which justifies intensive investigation into their production of PHAs. This review summarizes currently available knowledge on PHA production by Gram- positive bacteria especially Bacillus and Streptomyces. We hope that this will form the basis of further research into developing either or both as a source of PHAs for medical applications.
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Affiliation(s)
- Sabeel P Valappil
- Department of Molecular and Applied Biosciences, School of Biosciences, University of Westminster, 115 New Cavendish Street, London, W1W 6UW, UK
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Ramachander TVN, Rohini D, Belhekar A, Rawal SK. Synthesis of PHB by recombinant E. coli harboring an approximately 5 kb genomic DNA fragment from Streptomyces aureofaciens NRRL 2209. Int J Biol Macromol 2002; 31:63-9. [PMID: 12559428 DOI: 10.1016/s0141-8130(02)00068-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An approximately 5.0 kb Sau3A I genomic DNA fragment from Streptomyces aureofaciens NRRL 2209 was cloned in a plasmid vector and introduced into Escherichia coli. The recombinant E. coli accumulated polyhydroxyalkanoates (PHAs) as cytoplasmic inclusions. The accumulated PHA was identified as the isotactic homopolymer of PHB with a molecular weight of 2.85x10(5). Purified PHB granules were spherical with an average size of 1.1 microm and of stable configuration. DSC thermogram suggested high crystalline nature of the polymer. Maximum thermal degradation of the biopolymer occurred between 250 and 340 degrees C. Recombinant E. coli cells preferentially utilized glycerol as the carbon source and accumulated 25-28 times more PHB than the native S. aureofaciens.
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Affiliation(s)
- T V N Ramachander
- Plant Tissue Culture, National Chemical Laboratory, 411008, Pune, India
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Verma S, Bhatia Y, Valappil SP, Roy I. A possible role of poly-3-hydroxybutyric acid in antibiotic production in Streptomyces. Arch Microbiol 2002; 179:66-9. [PMID: 12471506 DOI: 10.1007/s00203-002-0500-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2002] [Revised: 10/03/2002] [Accepted: 10/11/2002] [Indexed: 11/30/2022]
Abstract
The occurrence of poly-3-hydroxybutyric acid (PHB) in 12 different strains of the genus Streptomyces was investigated. Gas chromatographic estimation indicated that all the strains produced PHB and the range of maximum PHB accumulation was between 1.5 and 11.8% dry cell weight. PHB was isolated from Streptomyces coelicolor A3(2) M145 and characterized using Fourier transform-infrared (FT-IR) spectroscopy. The correlation between PHB utilization and antibiotic production in S. coelicolor A3(2) M145, was studied; results indicated a possible role of PHB as a carbon reserve material used for antibiotic production.
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Affiliation(s)
- Shivani Verma
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Hauz Khas, New Delhi-110016, India
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Wu K, Chung L, Revill WP, Katz L, Reeves CD. The FK520 gene cluster of Streptomyces hygroscopicus var. ascomyceticus (ATCC 14891) contains genes for biosynthesis of unusual polyketide extender units. Gene 2000; 251:81-90. [PMID: 10863099 DOI: 10.1016/s0378-1119(00)00171-2] [Citation(s) in RCA: 209] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
FK520 (ascomycin) is a macrolide produced by Streptomyces hygroscopicus var. ascomyceticus (ATCC 14891) that has immunosuppressive, neurotrophic and antifungal activities. To further elucidate the biosynthesis of this and related macrolides, we cloned and sequenced an 80kb region encompassing the FK520 gene cluster. Genes encoding the three polyketide synthase (PKS) subunits (fkbB, fkbC and fkbA), the peptide synthetase (fkbP), the 31-O-methyltransferase (fkbM), the C-9 hydroxylase (fkbD) and the 9-hydroxyl oxidase (fkbO) had the same organization as the genes reported in the FK506 gene cluster of Streptomyces sp. MA6548 (Motamedi, H., Shafiee, A., 1998. The biosynthetic gene cluster for the macrolactone ring of the immunosuppressant FK506. Eur. J. Biochem. 256, 528-534). Disruption of a PKS gene in the cluster using the φC31 phage vector, KC515, led to antibiotic non-producing strains, proving the identity of the cluster. Previous labeling data have indicated that FK520 biosynthesis uses novel polyketide extender units (Byrne, K.M., Shafiee, A., Nielson, J., Arison, B., Monaghan, R.L., Kaplan, L., 1993. The biosynthesis and enzymology of an immunosuppressant, immunomycin, produced by Streptomyces hygroscopicus var, ascomyceticus. Dev. Ind. Microbiol. 32, 29-45). Genes in the flanking regions of the FK520 cluster were identified that appear to be involved in synthesis of these extender units. All but two of these genes were homologous to genes with known function. In addition to a crotonyl-CoA reductase gene (fkbS), at least two other genes are proposed to be involved in biosynthesis of the atypical PKS extender unit ethylmalonyl-CoA, which accounts for the ethyl side chain on C-21 of FK520. A set of five contiguous genes (fkbGHIJK) is proposed to be involved in biosynthesis of an unusual PKS extender unit bearing an oxygen on the alpha-carbon, and leading to the 13- and 15-methoxy side chains. These putative precursor synthesis genes in the flanking regions of the FK520 cluster are not found in the flanking regions of the rapamycin cluster (Molnár, I., Aparicio, J.F., Haydock, S.F., Khaw, L.E., Schwecke, T., König, A., Staunton, J., Leadlay, P.F., 1996. Organisation of the biosynthetic gene cluster for rapamycin in Streptomyces hygroscopicus: analysis of genes flanking the polyketide synthase. Gene 169, 1-7), consistent with labeling data showing that rapamycin biosynthesis uses only malonyl and methylmalonyl extender units.
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Affiliation(s)
- K Wu
- Kosan Biosciences Inc., Hayward, CA 94545, USA
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