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Dev MJ, Mahajan GB, Warke RG, Warke GM, Patil TA, Satardekar MR, Dalvi RC, Singhal RS. Mutagenesis enhances gellan gum production by a novel Sphingomonas spp.: upstream optimization, kinetic modeling, and structural and physico-functional evaluation. Int Microbiol 2024; 27:459-476. [PMID: 37495894 DOI: 10.1007/s10123-023-00399-1] [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: 02/24/2023] [Revised: 06/11/2023] [Accepted: 07/07/2023] [Indexed: 07/28/2023]
Abstract
Gellan gum (GG) has gained tremendous attention owing to its diversified applications. However, its high production and hence market cost are still a bottleneck in its widespread utilization. In the present study, high GG producing mutant of Sphingomonas spp. was developed by random mutagenesis using ethyl methylsulphonate (EMS) for industrial fermentation and identified as Sphingomonas trueperi after 16S rRNA and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) analysis. The fermentation conditions such as pH, temperature, and inoculum ratio were optimized by one factor at a time (OFAT) followed by screening of medium components by the Plackett-Burman statistical design. The most critical nutrients were further optimized by response surface methodology for maximizing GG production. The effect of dissolved oxygen tension in bioreactor on cell growth, substrate consumption, GG production, and batch productivity was elucidated. The highest GG titer (23 ± 2.4 g/L) was attained in optimized medium at 10% inoculum (6.45 ± 0.5 log cfu/mL) under controlled fermentation conditions of pH (7), temperature (30 °C), agitation (300-600 rpm), and aeration (0.5-2.0 SLPM) at 22 ± 2% dissolved oxygen tension in a 10-L bioreactor. Kinetic modeling of optimized batch process revealed that logistic growth model could best explain biomass accumulation, while GG formation and substrate consumption were best explained by Luedeking-Piret and exponential decay model, respectively. Structural and physico-functional features of GG produced by mutant Sphingomonas spp. were characterized by HPLC, FTIR, NMR, DSC, TGA, GPC, SEM, and rheological analysis. The higher productivity (0.51 g/L/h) under optimized fermentation conditions suggests potential consideration of mutant and process for commercial utilization.
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Affiliation(s)
- Manoj J Dev
- Food Engineering and Technology Department, Institute of Chemical Technology, Mumbai, 400019, India
- Department of Microbiology, HiMedia Laboratories Pvt. Ltd, Mumbai, India
| | - Girish B Mahajan
- Department of Microbiology, HiMedia Laboratories Pvt. Ltd, Mumbai, India
| | - Rahul G Warke
- Department of Microbiology, HiMedia Laboratories Pvt. Ltd, Mumbai, India
| | - Gangadhar M Warke
- Department of Microbiology, HiMedia Laboratories Pvt. Ltd, Mumbai, India
| | - Tanuja A Patil
- Department of Microbiology, HiMedia Laboratories Pvt. Ltd, Mumbai, India
| | - Milan R Satardekar
- Department of Microbiology, HiMedia Laboratories Pvt. Ltd, Mumbai, India
| | - Rachana C Dalvi
- Department of Microbiology, HiMedia Laboratories Pvt. Ltd, Mumbai, India
| | - Rekha S Singhal
- Food Engineering and Technology Department, Institute of Chemical Technology, Mumbai, 400019, India.
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Cai Z, Guo Y, Ma A, Zhang H. NMR analysis of the side-group substituents in welan gum in comparison to gellan gum. Int J Biol Macromol 2024; 254:127847. [PMID: 37924910 DOI: 10.1016/j.ijbiomac.2023.127847] [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: 04/12/2023] [Revised: 10/02/2023] [Accepted: 10/31/2023] [Indexed: 11/06/2023]
Abstract
The physicochemical properties and applications of polysaccharides are highly dependent on their chemical structures, including the monosaccharide composition, degree of substitution, and position of substituent groups in the backbone. The occurrence of side groups or side chains in the chain backbone of polysaccharides is often an essential factor influencing their conformational and physicochemical properties. Welan gum produced by the fermentation of Sphingomonas sp. ATCC 31555 microorganisms has been widely used in food, construction, and oil drilling fields. While understanding the physicochemical properties of welan gum solution has been highly developed, there is still little information about the determination strategy of the glycosyl side groups in welan gum. In this study, the NMR method was established to quantitatively determine the substituent groups in the chain backbone of welan gum. The delicate chemical structures of welan gum obtained at different fermentation conditions were clarified. The composition and content of side substituents were also identified by high-performance liquid chromatography to confirm the accuracy of NMR analysis. The quantitative determination of substituent groups in gellan gum based on NMR analysis was also elaborated for comparison. This work provides insights for profoundly understanding the structure-function relationship of welan gum.
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Affiliation(s)
- Zhixiang Cai
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Shanghai Key Laboratory of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yalong Guo
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Shanghai Key Laboratory of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Aiqin Ma
- Department of Nutrition, Affiliated Sixth People's Hospital South Campus, Shanghai Jiao Tong University, Shanghai 201499, China.
| | - Hongbin Zhang
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Shanghai Key Laboratory of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, Shanghai 200240, China.
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Li H, Zhang Z, Liu J, Guo Z, Chen M, Li B, Xue H, Ji S, Li H, Qin L, Zhu L, Wang J, Zhu H. Identification of the Key Enzymes in WL Gum Biosynthesis and Critical Composition in Viscosity Control. Front Bioeng Biotechnol 2022; 10:918687. [PMID: 35711643 PMCID: PMC9197254 DOI: 10.3389/fbioe.2022.918687] [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: 04/12/2022] [Accepted: 05/06/2022] [Indexed: 11/13/2022] Open
Abstract
As an important microbial exopolysaccharide, the sphingan WL gum could be widely used in petroleum, food, and many other fields. However, its lower production is still limiting its wider application. Therefore, to gain insights into the bottlenecks of WL gum production by identifying the key enzymes in the WL gum biosynthesis pathway, more than 20 genes were over-expressed in Sphingomonas sp. WG and their effects on WL gum production and structure were investigated. Compared to the control strain, the WL gum production of welB over-expression strain was increased by 19.0 and 21.0% at 36 and 84 h, respectively. The WL gum production of both atrB and atrD over-expression strains reached 47 g/L, which was approximately 34.5% higher than that of the control strain at 36 h. Therefore, WelB, AtrB, and AtrD may be the key enzymes in WL production. Interestingly, the broth viscosity of most over-expression strains decreased, especially the welJ over-expression strain whose viscosity decreased by 99.3% at 84 h. Polysaccharides' structural features were investigated to find the critical components in viscosity control. The uronic acid content and total sugar content was affected by only a few genes, therefore, uronic acid and total sugar content may be not the key composition. In comparison, the acetyl degrees were enhanced by over-expression of most genes, which meant that acetyl content may be the critical factor and negatively correlated with the apparent viscosity of WL gum. This work provides useful information on the understanding of the bottlenecks of WL gum biosynthesis and will be helpful for the construction of high WL gum-yielding strains and rheological property controlling in different industries.
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Affiliation(s)
- Hui Li
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Zaimei Zhang
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Jianlin Liu
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Zhongrui Guo
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Mengqi Chen
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Benchao Li
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Han Xue
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Sixue Ji
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Hang Li
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Lijian Qin
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Ling Zhu
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Jiqian Wang
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China
| | - Hu Zhu
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, China.,Engineering Research Center of Industrial Biocatalysis, Fujian-Taiwan Science and Technology Cooperation Base of Biomedical Materials and Tissue Engineering, College of Chemistry and Materials Science, Fujian Normal University, Fuzhou, China.,College of Chemical Engineering and Materials Science, Quanzhou Normal University, Quanzhou, China
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Li B, Li H, Liu J, Zhang Z, Chen M, Yue L, Lu W, Ji S, Wang D, Zhu H, Wang J. Enzymatic degradation, antioxidant and rheological properties of a sphingan WL gum from Sphingomonas sp. WG. Int J Biol Macromol 2022; 210:622-629. [PMID: 35508228 DOI: 10.1016/j.ijbiomac.2022.04.218] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 04/24/2022] [Accepted: 04/28/2022] [Indexed: 11/25/2022]
Abstract
A molecular weight (Mw) controllable degradation strategy using the lyase WelR as the efficient tool was established, and the relationship between the Mw and the rheological properties and antioxidant activity of WL gum was systematically investigated. Four different WL samples WL1-WL4 with a gradient Mw change (from 4.70 × 106 to 1.45 × 106 Da) were obtained by controlling the enzymatic reaction conditions. As the Mw decreased, its apparent viscosity, intrinsic viscosity, viscous modulus (G″) and elastic modulus (G') decreased. More interestingly, in contrast to the native WL, the G″ of the degraded WL became higher than G'. Besides, the biodegraded WL samples possessed much higher hydroxyl radicals scavenging activity than the original WL. WL4 with the lowest Mw showed the highest HO radical scavenging activity, about 94.65% at 1 mg/mL. This work provided a useful method to obtain a series of WL samples with controllable Mw and properties, which will broaden the application of sphingans.
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Affiliation(s)
- Benchao Li
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong, People's Republic of China
| | - Hui Li
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong, People's Republic of China
| | - Jianlin Liu
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong, People's Republic of China
| | - Zaimei Zhang
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong, People's Republic of China
| | - Mengqi Chen
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong, People's Republic of China
| | - Lin Yue
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong, People's Republic of China
| | - Wei Lu
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong, People's Republic of China
| | - Sixue Ji
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong, People's Republic of China
| | - Dong Wang
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong, People's Republic of China
| | - Hu Zhu
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong, People's Republic of China; Engineering Research Center of Industrial Biocatalysis, Fujian Province Universities, College of Chemistry and Materials Science, Fujian Normal University, Fuzhou, Fujian, People's Republic of China; College of Chemical Engineering and Materials Science, Quanzhou Normal University, Quanzhou 362000, People's Republic of China.
| | - Jiqian Wang
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong, People's Republic of China.
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Gao M, Li H, Yang T, Li Z, Hu X, Wang Z, Jiang Y, Zhu L, Zhan X. Production of prebiotic gellan oligosaccharides based on the irradiation treatment and acid hydrolysis of gellan gum. Carbohydr Polym 2022; 279:119007. [PMID: 34980352 DOI: 10.1016/j.carbpol.2021.119007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 11/30/2022]
Abstract
Biologically active gellan oligosaccharides (GOSs), newly found plant elicitors and biostimulants, are produced from the hydrolysis of gellan gum. Traditional hydrolysis with concentrated acid suffers from the problems of high pollution and low functional oligosaccharide yield because the process is difficult to control. Irradiation (60Co γ-ray) with a dosage ranging from 0 kGy to 175 kGy was used to degrade gellan gum efficiently and cleanly into low molecular weight (Mw) gellan with an average Mw ranging from 449,119 Da to 72,903 Da. The low Mw gellan irradiated at 70 kGy was further hydrolyzed with low concentration acid (0.5 mol/L HCl) to produce GOSs with DPs mainly 4 and 8, indicating that the Rha-β-(1 → 3)-Glc bonds in gellan gum were easily cut to produce residues with tetrasaccharide repeat subunits. Besides antioxidant activity, GOSs were also proved with prebiotic activity by in vitro fecal fermentation in a self-designed bionic intestinal reactor.
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Affiliation(s)
- Minjie Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Hongyu Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Tianyi Yang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Zhitao Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xiuyu Hu
- China Biotech Fermentation Industry Association, Beijing 100833, China
| | - Zichao Wang
- College of Biological Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Yun Jiang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Li Zhu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xiaobei Zhan
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
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7
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Cloning and expression of gellan gum biosynthetic genes gelQ, gelB, gelL and gel K of Sphingomonas paucimobilis, production and characterization of the recombinant gellan gum. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2020. [DOI: 10.1016/j.bcab.2020.101850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Ding Y, Jiang F, Chen L, Lyu W, Chi Z, Liu C, Chi Z. An Alternative Hard Capsule Prepared with the High Molecular Weight Pullulan and Gellan: Processing, Characterization, and In Vitro Drug Release. Carbohydr Polym 2020; 237:116172. [DOI: 10.1016/j.carbpol.2020.116172] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/12/2020] [Accepted: 03/12/2020] [Indexed: 12/11/2022]
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Palumbo FS, Federico S, Pitarresi G, Fiorica C, Giammona G. Gellan gum-based delivery systems of therapeutic agents and cells. Carbohydr Polym 2020; 229:115430. [DOI: 10.1016/j.carbpol.2019.115430] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/16/2019] [Accepted: 10/02/2019] [Indexed: 01/23/2023]
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Structure and chain conformation characteristics of high acyl gellan gum polysaccharide in DMSO with sodium nitrate. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.09.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Klamor S, Schröder M, Brunklaus G, Niehoff P, Berkemeier F, Schappacher FM, Winter M. On the interaction of water-soluble binders and nano silicon particles: alternative binder towards increased cycling stability at elevated temperatures. Phys Chem Chem Phys 2015; 17:5632-41. [PMID: 25623421 DOI: 10.1039/c4cp04090b] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Silicon based composites are among the most promising negative electrodes for lithium ion battery applications due to their high theoretical capacities. One major drawback of silicon based anodes are their large volume changes during lithiation and delithiation. Although many efforts have been made in view of new binder materials and improved electrolytes, the resulting battery cell suffers from severe capacity fading at ambient or elevated temperatures, respectively. The strong reactivity with the electrolyte is considered to be responsible for the reduced cycle life at elevated temperatures. In this work we introduce silicon composite anodes with a novel composition based on a gellan gum binder material that show an improved cycling performance at ambient temperature and at 60 °C. To elucidate the influence of the binder material, we investigated the structure of the silicon based composite anodes in order to understand the nature of the interaction of the gellan gum based binder polymers with the silicon particles in comparison with a common CMC binder. Also the influence of the choice of binder on the interactions at the interface between electrode surface and electrolyte were studied. A combination of powerful techniques including solid state NMR, TEM and EELS, XPS as well as FTIR were applied.
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Affiliation(s)
- S Klamor
- MEET Battery Research Center, University of Münster, 48149 Münster, Germany.
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14
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Screening of gellan gum as an ionic and hydrophobic chromatographic matrix for biomolecules purification. Sep Purif Technol 2014. [DOI: 10.1016/j.seppur.2014.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Murillo-Martínez MM, Tecante A. Preparation of the sodium salt of high acyl gellan and characterization of its structure, thermal and rheological behaviors. Carbohydr Polym 2014; 108:313-20. [DOI: 10.1016/j.carbpol.2014.02.056] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 01/30/2014] [Accepted: 02/09/2014] [Indexed: 11/16/2022]
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Gellan sulfate inhibits Plasmodium falciparum growth and invasion of red blood cells in vitro. Sci Rep 2014; 4:4723. [PMID: 24740150 PMCID: PMC3989555 DOI: 10.1038/srep04723] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 04/01/2014] [Indexed: 11/08/2022] Open
Abstract
Here, we assessed the sulfated derivative of the microbial polysaccharide gellan gum and derivatives of λ and κ-carrageenans for their ability to inhibit Plasmodium falciparum 3D7 and Dd2 growth and invasion of red blood cells in vitro. Growth inhibition was assessed by means of flow cytometry after a 96-h exposure to the inhibitors and invasion inhibition was assessed by counting ring parasites after a 20-h exposure to them. Gellan sulfate strongly inhibited invasion and modestly inhibited growth for both P. falciparum 3D7 and Dd2; both inhibitory effects exceeded those achieved with native gellan gum. The hydrolyzed λ-carrageenan and oversulfated κ-carrageenan were less inhibitory than their native forms. In vitro cytotoxicity and anticoagulation assays performed to determine the suitability of the modified polysaccharides for in vivo studies showed that our synthesized gellan sulfate had low cytotoxicity and anticoagulant activity.
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Gonçalves A, Rocha L, Dias J, Passarinha L, Sousa A. Optimization of a chromatographic stationary phase based on gellan gum using central composite design. J Chromatogr B Analyt Technol Biomed Life Sci 2014; 957:46-52. [DOI: 10.1016/j.jchromb.2014.02.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 01/17/2014] [Accepted: 02/10/2014] [Indexed: 01/27/2023]
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18
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Mazzuca C, Micheli L, Carbone M, Basoli F, Cervelli E, Iannuccelli S, Sotgiu S, Palleschi A. Gellan hydrogel as a powerful tool in paper cleaning process: A detailed study. J Colloid Interface Sci 2014; 416:205-11. [DOI: 10.1016/j.jcis.2013.10.062] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/17/2013] [Accepted: 10/21/2013] [Indexed: 10/26/2022]
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Gonzalez RE, Salazar JA, Pérez JA. Obtención de microcapsulas de tamaño controlado conteniendo Lactococcus lactis, utilizando mezclas de gelanos de alto y bajo acilo. REVISTA COLOMBIANA DE BIOTECNOLOGÍA 2013. [DOI: 10.15446/rev.colomb.biote.v15n2.35808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Kuźma M, Clack B, Edwards J, Tylingo R, Samaszko J, Madaj J. Structure and properties of the exopolysaccharides produced by Pseudomonas mutabilis T6 and P. mutabilis ATCC 31014. Carbohydr Res 2011; 348:84-90. [PMID: 22177926 DOI: 10.1016/j.carres.2011.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 11/08/2011] [Accepted: 11/12/2011] [Indexed: 11/19/2022]
Abstract
This paper presents a study on the purification, primary structure, and rheological properties of exopolysaccharides isolated from cultures of Pseudomonas mutabilis T6 and P. mutabilis ATCC 31014. Both polymers are exopolysaccharides of D-mannose. The mannan isolated from P. mutabilis T6 contains on average about 5% of residual β-D-glucose, in contrast to the mannan from P. mutabilis ATCC 31014, which contained only trace amounts of residual β-D-glucose (less than 1%). Based on the (13)C NMR spectra, all of the remaining carbohydrates in the exopolysaccharides occur in the form of pyranose rings. All of the mannose residues have the α configuration at the anomeric carbon atom while the glucose adopts the β configuration. The reaction of both polysaccharide hydrolysates with an optically active alcohol indicates that all of the sugar residues have the D configuration. We found that the main chain of the exopolysaccharide is composed of mannose residues connected through α-(1→6) linkages, of which a large number are substituted on O2 with D-mannose and the remaining are substituted with di- to pentasaccharide fragments. The rheological properties of the exopolysaccharide isolated from P. mutabilis T6 show that its viscosity is over 30 times greater than that of P. mutabilis ATCC 31014.
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Affiliation(s)
- Monika Kuźma
- Faculty of Chemistry, University of Gdańsk, Gdańsk Sobieskiego 18, 80-952 Gdańsk, Poland
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Redouan E, Emmanuel P, Michelle P, Bernard C, Josiane C, Cédric D. Evaluation of antioxidant capacity of ulvan-like polymer obtained by regioselective oxidation of gellan exopolysaccharide. Food Chem 2011; 127:976-83. [DOI: 10.1016/j.foodchem.2011.01.067] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 11/14/2010] [Accepted: 01/18/2011] [Indexed: 02/04/2023]
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24
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Effects of carbon/nitrogen ratio, dissolved oxygen and impeller type on gellan gum production in Sphingomonas paucimobilis. ANN MICROBIOL 2011. [DOI: 10.1007/s13213-011-0261-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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25
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Wu X, Li O, Chen Y, Zhu L, Qian C, Teng Y, Tao X. A carotenoid-free mutant strain of Sphingomonas paucimobilis ATCC 31461 for the commercial production of gellan. Carbohydr Polym 2011. [DOI: 10.1016/j.carbpol.2011.01.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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26
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Preparation, characterization and biological properties of Gellan gum films with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide cross-linker. Carbohydr Polym 2010. [DOI: 10.1016/j.carbpol.2010.06.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Redouan E, Emmanuel P, Christine B, Bernard C, Josiane C, Cédric D. Development of new ulvan-like polymer by regioselective oxidation of gellan exopolysaccharide using TEMPO reagent. Carbohydr Polym 2010. [DOI: 10.1016/j.carbpol.2009.12.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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28
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Rocha J, Granja AT, Sá-Correia I, Fialho A, Frazão C. Cloning, expression, purification, crystallization and preliminary crystallographic studies of UgdG, an UDP-glucose dehydrogenase from Sphingomonas elodea ATCC 31461. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:69-72. [PMID: 20057075 PMCID: PMC2805541 DOI: 10.1107/s174430910904929x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 11/18/2009] [Indexed: 11/10/2022]
Abstract
Gellan gum, a commercial gelling agent produced by Sphingomonas elodea ATCC 31461, is a high-value microbial exopolysaccharide. UDP-glucose dehydrogenase (UGD; EC 1.1.1.22) is responsible for the NAD-dependent twofold oxidation of UDP-glucose to UDP-glucuronic acid, one of the key components for gellan biosynthesis. S. elodea ATCC 31461 UGD, termed UgdG, was cloned, expressed, purified and crystallized in native and SeMet-derivatized forms in hexagonal and tetragonal space groups, respectively; the crystals diffracted X-rays to 2.40 and 3.40 A resolution, respectively. Experimental phases were obtained for the tetragonal SeMet-derivatized crystal form by a single-wavelength anomalous dispersion experiment. This structure was successfully used as a molecular-replacement probe for the hexagonal crystal form of the native protein.
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Affiliation(s)
- Joana Rocha
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2781-901 Oeiras, Portugal
| | - Ana Teresa Granja
- Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico, 1049-001 Lisbon, Portugal
| | - Isabel Sá-Correia
- Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico, 1049-001 Lisbon, Portugal
| | - Arsénio Fialho
- Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico, 1049-001 Lisbon, Portugal
| | - Carlos Frazão
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2781-901 Oeiras, Portugal
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29
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Gonçalves VM, Reis A, Domingues MRM, Lopes-da-Silva JA, Fialho AM, Moreira LM, Sá-Correia I, Coimbra MA. Structural analysis of gellans produced by Sphingomonas elodea strains by electrospray tandem mass spectrometry. Carbohydr Polym 2009. [DOI: 10.1016/j.carbpol.2008.11.035] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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30
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Michaud P, Da Costa A, Courtois B, Courtois J. Polysaccharide Lyases: Recent Developments as Biotechnological Tools. Crit Rev Biotechnol 2008; 23:233-66. [PMID: 15224891 DOI: 10.1080/07388550390447043] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Polysaccharide lyases, which are polysaccharide cleavage enzymes, act mainly on anionic polysaccharides. Produced by prokaryote and eukaryote organisms, these enzymes degrade (1,4) glycosidic bond by a beta elimination mechanism and have unsaturated oligosaccharides as major products. New polysaccharides are cleaved only by their specific polysaccharide lyases. From anionic polysaccharides controlled degradations, various biotechnological applications were investigated. This review catalogues the degradation of bacterial, plant and animal polysaccharides (neutral and anionic) by this family of carbohydrate acting enzymes.
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Affiliation(s)
- P Michaud
- Laboratoire des Glucides--LPMV, IUT/Génie Biologique, Université de Picardie Jules Verne, Avenue des Facultés, Le Bailly, 80025 Amiens Cedex, France.
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31
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Occurrence, production, and applications of gellan: current state and perspectives. Appl Microbiol Biotechnol 2008; 79:889-900. [DOI: 10.1007/s00253-008-1496-0] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2008] [Revised: 04/03/2008] [Accepted: 04/05/2008] [Indexed: 10/22/2022]
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32
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Functional biopolymers produced by biochemical technology considering applications in food engineering. KOREAN J CHEM ENG 2007. [DOI: 10.1007/s11814-007-0047-1] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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33
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Granja AT, Popescu A, Marques AR, Sá-Correia I, Fialho AM. Biochemical characterization and phylogenetic analysis of UDP-glucose dehydrogenase from the gellan gum producer Sphingomonas elodea ATCC 31461. Appl Microbiol Biotechnol 2007; 76:1319-27. [PMID: 17668199 DOI: 10.1007/s00253-007-1112-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 07/03/2007] [Accepted: 07/04/2007] [Indexed: 10/23/2022]
Abstract
Sphingomonas elodea ATCC 31461 synthesizes in high yield the exopolysaccharide gellan, which is a water-soluble gelling agent with many applications. In this study, we describe the cloning and sequence analysis of the ugdG gene, encoding a UDP-glucose dehydrogenase (47.2 kDa; UDPG-DH; EC 1.1.1.22), required for the synthesis of the gellan gum precursor UDP-glucuronic acid. UgdG protein shows homology to members of the UDP-glucose/GDP-mannose dehydrogenase superfamily. The Neighbor-Joining method was used to determine phylogenetic relationships among prokaryotic and eukaryotic UDPG-DHs. UgdG from S. elodea and UDPG-DHs from Novosphingobium, Zymomonas, Agrobacterium, and Caulobacter species form a divergent phylogenetic group with a close evolutionary relationship with eukaryotic UDPG-DHs. The ugdG gene was recombinantly expressed in Escherichia coli with and N-terminal 6-His tag and purified for biochemical characterization. The enzyme has an optimum temperature and pH of 37 degrees C and 8.7, respectively. The estimated apparent K(m) values for UDP-glucose and NAD(+) were 0.87 and 0.4 mM, respectively. DNA sequencing of chromosomal regions adjacent to ugdG gene and sequence similarity studies suggests that this gene maps together with others presumably involved in the biosynthesis of S. elodea cell wall polysaccharides.
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Affiliation(s)
- Ana Teresa Granja
- IBB - Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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34
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Singh BN, Kim KH. Characterization and relevance of physicochemical interactions among components of a novel multiparticulate formulation for colonic delivery. Int J Pharm 2007; 341:143-51. [PMID: 17509782 DOI: 10.1016/j.ijpharm.2007.04.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2007] [Revised: 04/01/2007] [Accepted: 04/02/2007] [Indexed: 10/23/2022]
Abstract
The primary objective of this study was to investigate potential interactions among a model drug (azathioprine; AZA), polymers and a divalent metal ion, which were utilized in the development of a novel multiparticulate formulation for colonic delivery. The approach involved preparation of beads by ionotropic gelation of deacylated gellan gum (DGG) in the presence of Ca(2+) ions, followed by coating with Eudragit S-100. Various possible physicochemical interactions among formulation components were characterized by DSC, FT-IR, XRPD, (1)H-NMR, and an isothermal stress test. Results of isothermal stress testing indicated that there was no significant interaction of AZA with DGG and Eudragit S-100. However, results of DSC and XRPD studies suggested that there could be interactions between AZA and DGG, and ionotropic gelation can affect the physical state of AZA, which may have implications for drug release characteristics and, physical and chemical stability. The results of FT-IR studies were suggestive of interactions of DGG with AZA and Eudragit S-100, and provided evidence for interactions of AZA and DGG with Ca(2+) ions. The electrostatic interaction of DGG with Ca(2+) was also supported by results of DSC studies while that between AZA and Ca(2+) was confirmed by (1)H-NMR studies. This study, to our knowledge, is first reported investigation in which the unique thermal property of gellan gum gels, and possible interactions between a drug and counter ions of an ionotropic agent have been demonstrated through bead characterization studies. The formation of AZA-Ca(2+) complex could have an impact on drug release kinetics, product stability and clinical efficacy for treatment of inflammatory bowel diseases or other diseases, which merit further investigation.
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Affiliation(s)
- Brahma N Singh
- Drug Delivery Systems Research Laboratory, College of Pharmacy and Allied Health Professions, St. John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA.
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35
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Banik RM, Santhiagu A. Improvement in Production and Quality of Gellan Gum by Sphingomonas paucimobilis Under High Dissolved Oxygen Tension Levels. Biotechnol Lett 2006; 28:1347-50. [PMID: 16820976 DOI: 10.1007/s10529-006-9098-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Accepted: 05/02/2006] [Indexed: 01/13/2023]
Abstract
The effect of agitation rate and dissolved oxygen tension (DOT) on growth and gellan production by Sphingomonas paucimobilis was studied. Higher cell growth of 5.4 g l(-1) was obtained at 700 rpm but maximum gellan (15 g l(-1)) was produced at 500 rpm. DOT levels above 20% had no effect on cell growth but gellan yield was increased to 23 g l(-1 )with increase in DOT level to 100%. Higher DOT levels improved the viscosity and molecular weight of the polymer with change in acetate and glycerate content of the polymer.
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Affiliation(s)
- R M Banik
- School of Biochemical Engineering, Institute of Technology, Banaras Hindu University, Varanasi 221 005, India
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36
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Wang X, Xu P, Yuan Y, Liu C, Zhang D, Yang Z, Yang C, Ma C. Modeling for gellan gum production by Sphingomonas paucimobilis ATCC 31461 in a simplified medium. Appl Environ Microbiol 2006; 72:3367-74. [PMID: 16672479 PMCID: PMC1472386 DOI: 10.1128/aem.72.5.3367-3374.2006] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Accepted: 03/02/2006] [Indexed: 11/20/2022] Open
Abstract
Gellan gum production was carried out by Sphingomonas paucimobilis ATCC 31461 in a simplified medium with a short incubation time, and a kinetic model for understanding, controlling, and optimizing the fermentation process was proposed. The results revealed that glucose was the best carbon source and that the optimal concentration was 30 g liter(-1). As for the fermenting parameters, considerably large amounts of gellan gum were yielded by an 8-h-old culture and a 4% inoculum at 200 rpm on a rotary shaker. Under the optimized conditions, the maximum level of gellan gum (14.75 g liter(-1)) and the highest conversion efficiency (49.17%) were obtained in a 30-liter fermentor in batch fermentation. Logistic and Luedeking-Piret models were confirmed to provide a good description of gellan gum fermentation, which gave some support for the study of gellan gum fermentation kinetics. Additionally, this study is the first demonstration that gellan gum production is largely growth associated by analysis of kinetics in its batch fermentation process. Based on model prediction, higher gellan gum production (17.71 g liter(-1)) and higher conversion efficiency (57.12%) were obtained in fed-batch fermentation at the same total glucose concentration (30 g liter(-1)).
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Affiliation(s)
- Xia Wang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People's Republic of China
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37
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Silva E, Marques AR, Fialho AM, Granja AT, Sá-Correia I. Proteins encoded by Sphingomonas elodea ATCC 31461 rmlA and ugpG genes, involved in gellan gum biosynthesis, exhibit both dTDP- and UDP-glucose pyrophosphorylase activities. Appl Environ Microbiol 2005; 71:4703-12. [PMID: 16085866 PMCID: PMC1183319 DOI: 10.1128/aem.71.8.4703-4712.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The commercial gelling agent gellan is a heteropolysaccharide produced by Sphingomonas elodea ATCC 31461. In this work, we carried out the biochemical characterization of the enzyme encoded by the first gene (rmlA) of the rml 4-gene cluster present in the 18-gene cluster required for gellan biosynthesis (gel cluster). Based on sequence homology, the putative rml operon is presumably involved in the biosynthesis of dTDP-rhamnose, the sugar necessary for the incorporation of rhamnose in the gellan repeating unit. Heterologous RmlA was purified as a fused His6-RmlA protein from extracts prepared from Escherichia coli IPTG (isopropyl-beta-D-thiogalactopyranoside)-induced cells, and the protein was proven to exhibit dTDP-glucose pyrophosphorylase (Km of 12.0 microM for dTDP-glucose) and UDP-glucose pyrophosphorylase (Km of 229.0 microM for UDP-glucose) activities in vitro. The N-terminal region of RmlA exhibits the motif G-X-G-T-R-X2-P-X-T, which is highly conserved among bacterial XDP-sugar pyrophosphorylases. The motif E-E-K-P, with the conserved lysine residue (K163) predicted to be essential for glucose-1-phosphate binding, was observed. The S. elodea ATCC 31461 UgpG protein, encoded by the ugpG gene which maps outside the gel cluster, was previously identified as the UDP-glucose pyrophosphorylase involved in the formation of UDP-glucose, also required for gellan synthesis. In this study, we demonstrate that UgpG also exhibits dTDP-glucose pyrophosphorylase activity in vitro and compare the kinetic parameters of the two proteins for both substrates. DNA sequencing of ugpG gene-adjacent regions and sequence similarity studies suggest that this gene maps with others involved in the formation of sugar nucleotides presumably required for the biosynthesis of another cell polysaccharide(s).
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Affiliation(s)
- Elisabete Silva
- Biological Sciences Research Group, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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38
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Effects of monovalent cation and anion species on the conformation of gellan chains in aqueous systems. Carbohydr Polym 2005. [DOI: 10.1016/j.carbpol.2005.04.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Marques AR, Ferreira PB, Sá-Correia I, Fialho AM. Characterization of the ugpG gene encoding a UDP-glucose pyrophosphorylase from the gellan gum producer Sphingomonas paucimobilis ATCC 31461. Mol Genet Genomics 2003; 268:816-24. [PMID: 12655408 DOI: 10.1007/s00438-003-0805-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2002] [Accepted: 12/20/2002] [Indexed: 10/25/2022]
Abstract
The ugpGgene, which codes for a UDP-glucose pyrophosphorylase (UGP) (or glucose-1-phosphate uridylyltransferase; EC 2.7.7.9) in Sphingomonas paucimobilis ATCC 31461, was cloned and sequenced. This industrial strain produces the exopolysaccharide gellan, a new commercial gelling agent, and the ugpG gene may convert glucose-1-phosphate into UDP-glucose in the gellan biosynthetic pathway. The ugpG gene is capable of restoring the capacity of an Escherichia coli galU mutant to grow on galactose by functional complementation of its deficiency for UDP-glucose pyrophosphorylase activity. As expected, the predicted gene product shows strong homology to UDP-glucose pyrophosphorylases from several bacterial species. The N-terminal region of UgpG exhibits the motif GXGTRXLPXTK, which is highly conserved among bacterial XDP-sugar pyrophosphorylases, and a lysine residue (K(192)) is located within a VEKP motif predicted to be essential for substrate binding or catalysis. UgpG was purified to homogeneity as a heterologous fusion protein from crude cell extracts prepared from IPTG-induced cells of E. coli, using affinity chromatography. Under denaturing conditions, the fusion protein S-UgpG-His(6) migrated with an estimated molecular mass of 36 kDa [corresponding to the predicted molecular mass of native UgpG (31.2 kDa) plus 5 kDa for the S and histidine tags). Kinetic analysis of UgpG in the reverse reaction (pyrophosphorolysis) showed a typical Michaelis-Menten substrate saturation pattern. The apparent K(m) and V(max) values estimated for UDP-glucose were 7.5 microM and 1275 micromol/min/g.
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Affiliation(s)
- A R Marques
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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40
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Parija S, Misra M, Mohanty AK. STUDIES OF NATURAL GUM ADHESIVE EXTRACTS: AN OVERVIEW. ACTA ACUST UNITED AC 2001. [DOI: 10.1081/mc-100107775] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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41
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Abstract
A full assignment of high-field nmr spectra of gellan was obtained in dilute aqueous solution by performing a series of selective one-dimensional nmr experiments. The observed nuclear Overhauser effects (NOEs) cannot be interpreted assuming that each sugar residue is intrinsically rigid and in a chair conformation. In fact, the rhamnose residue gives strong NOE contacts coherent only with an equilibrium involving both a chair as well as a boat (or a hemiboat) conformation. Molecular dynamic calculations performed on a heptamer with a central rhamnose support the above finding, and show a structure based on a very stiff single chain in which it is present a flipping of the rhamnose residue. At low temperatures (5-20 degrees C) in very dilute solutions (0.018 mg/mL) nmr spectra show a splitting of the resonance due to the methyl group of rhamnose residue, thus confirming the presence of a slow equilibrium among different conformers.
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Affiliation(s)
- M Bosco
- Polytech, SCaRL AREA Science Park, Padriciano 99, I-34012 Trieste, Italy
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42
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Richau JA, Leitão JH, Correia M, Lito L, Salgado MJ, Barreto C, Cescutti P, Sá-Correia I. Molecular typing and exopolysaccharide biosynthesis of Burkholderia cepacia isolates from a Portuguese cystic fibrosis center. J Clin Microbiol 2000; 38:1651-5. [PMID: 10747161 PMCID: PMC86514 DOI: 10.1128/jcm.38.4.1651-1655.2000] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
This work describes the first epidemiological survey of Burkholderia cepacia involved in pulmonary infections among the Portuguese population with cystic fibrosis (CF) who attended the major CF treatment Center in Lisbon at Sta. Maria Hospital from 1995 to the end of 1997. The characterization of the genomic relatedness of the isolates was based on the analysis of their ribopatterns (with EcoRI) followed by construction of a ribotype-based phylogenetic tree. This study was complemented with macrorestriction fragment analysis by pulsed-field gel electrophoresis. After optimization of the solid growth medium, we found that exopolysaccharide (EPS) production by B. cepacia CF isolates is not as rare a phenomenon as was thought before; indeed, 70% of the isolates examined were EPS producers.
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Affiliation(s)
- J A Richau
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, 1049-001 Lisbon
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43
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Fialho, Martins, Donval, Leitao, Ridout, Jay, Morris, Sa-Correia. Structures and properties of gellan polymers produced by sphingomonas paucimobilis ATCC 31461 from lactose compared with those produced from glucose and from cheese whey. Appl Environ Microbiol 1999; 65:2485-91. [PMID: 10347031 PMCID: PMC91366 DOI: 10.1128/aem.65.6.2485-2491.1999] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/1998] [Accepted: 03/25/1999] [Indexed: 11/20/2022] Open
Abstract
The dairy industry produces large quantities of whey as a by-product of cheese production and is increasingly looking for new ways to utilize this waste product. Gellan gum is reliably produced by Sphingomonas paucimobilis in growth media containing lactose, a significant component of cheese whey, as a carbon source. We studied and compared polysaccharide biosynthesis by S. paucimobilis ATCC 31461 in media containing glucose, lactose (5 to 30 g/liter), and sweet cheese whey. We found that altering the growth medium can markedly affect the polysaccharide yield, acyl substitution level, polymer rheological properties, and susceptibility to degradation. Depression of gellan production from lactose compared with gellan production from glucose (approximately 30%) did not appear to occur at the level of synthesis of sugar nucleotides, which are the donors of monomers used for biosynthesis of the repetitive tetrasaccharide unit of gellan. The lactose-derived biopolymer had the highest total acyl content; the glucose- and whey-derived gellans had similar total acyl contents but differed markedly in their acetate and glycerate levels. Rheological studies revealed how the functionality of a gellan polysaccharide is affected by changes in the acyl substitution.
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Affiliation(s)
- Fialho
- Centro de Engenharia Biologica e Quimica, Instituto Superior Tecnico, 1049-001 Lisbon, Portugal
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