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Scanning electron micrograph showing VolcanielIa eurihalina cells attached to each other by means of an amorphous substance. Magnification x 10,000.
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Volcaniella eurihalina strain F2-7 synthesizes an exopolysaccharide named V2-7, primarily composed of glucose, mannose, and rhamnose. The effect
of chemical and physical factors on solution viscosity was studied. The V2-7 EPS showed pseudoplastic behavior at concentrations
over 0.5% w/v. Viscosity decreased with temperature, but the viscosity value...
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Ultrasonic degradation of a new exopolysaccharide WL-26 from Sphingomonas sp. was made over the frequency range 200 to 1200 Hz and polymer concentrations of 3, 5, 10 and 20 g/L using high performance anion exchange pulsed-amperometric detection chromatography (HPAEC–PAD) and infrared spectroscopy. Sonication was more efficient with less concentrate...
Citations
... MEOR utilizes the immobilization property of EPS for treating the residual oil following extraction using conventional methods. Thermally stable EPS with high viscosity obtained from Enterobacter cloacae and Volcaniellaeurihalina F2-7 has been applied for MEOR (Calvo et al. 1995;Chandran and Das 2011). Another polymer, xanthan, secreted mainly by Xanthomonas spp., is used for enhanced oil recovery; its use is restricted to low-temperature recovery procedures due to its temperature sensitivity (Shukla et al. 2019). ...
Bacterial cells dwelling in the Polycyclic Aromatic Hydrocarbons (PAH) contaminated ecosystem occur as an eco-community or biofilms having biosurfactants and exopolymeric substances (EPS) producing capacity. Bacteria have developed several mechanisms to utilize the low accessible PAH compounds by modifying their structural and physiological process. EPS provides an adsorption site for PAH binding and acts as an emulsifier, enhancing PAH uptake in bacterial cells. Biosurfactants aid in the solubilization of the low-bioavailable carbon sources by reducing the interfacial surface tension between the aqueous phase and PAH-sorbent matrix, solubilizing PAHs thus making them bioavailable. Mining of exopolysaccharides synthesizing key genes (priming Glycosyltransferase) and biosurfactant producing genes (synthetases) in PAH degrading bacteriomes established their concomitant involvement in PAH solubilization and uptake. The transcriptional and translational regulators (secondary messenger cyclic-di-GMP, quorum sensing molecules, small ribosomal RNAs, two-component signaling molecules) control the synthesis of these ‘bioavailability enhancers’ towards PAH utilization and have been elucidated explicitly in the current review.
... This method is used to immobilize the oil in the reservoir which is left behind after the application of conventional oil extraction methods by using microorganisms. Exopolysaccharides of Enterobacter cloaceae possess good viscosity at high temperature and Volcaniella eurihalina F2-7 is known to synthesize an exopolysaccharide, the rheological properties of which are stable to pH and inorganic salts, which makes them a probable candidate for microbial enhanced oil recovery [148,149]. Moreover, it is also used as additive in drilling fluid due to its salt compatibility and resistance to thermal degradation [151]. ...
Microorganisms can utilize an extensive assortment of carbon and nitrogen sources as well as various added nutrients ranging from simple to complex. Depending on the microbe and the metabolic pathway they undergo, these nutrients are efficiently converted into complex and diverse biopolymers with varied physico-chemical properties. Exopolysaccharides (EPS) are biopolymers that primarily contain- carbohydrates. The extensively studied EPS producing bacteria include Leuconostoc mesenteroides, Xanthomonas campestris, Acinetobacter calcoaceticus, Lactobacillus sp. and Alkaligenes sp. However, some prominent fungal exopolysaccharides produced by Aspergillus niger, Lentinula edodes, Fusarium solani, Botryosphaeria rhodina, Coriolus versicolor have also been put to commercial use. While the microbes may vary substantially in their physiology, the production of EPS depends largely on the optimization of the growth by varying various parameters influencing growth and the meticulous designing of its production media. EPS acts as an invaluable asset for the producing microbe by providing manifold benefits including but not restricted to: protection against- desiccation, starvation, phagocytosis, UV radiation, environmental stress and water retention. Being eco-friendly and biodegradable, major microbial EPS such as; dextran, xanthan, alginate, hyaluronan, pullulan, chitosan and lentinam have found numerous vital applications in pharmaceutical, agriculture, food and cosmetics industries. This review provides an inclusive insight into the world of microbial exopolysaccharides covering its major aspects, namely- its types, biosynthesis and the factors that influence its production along with various techniques used for its recovery and further characterization. Special emphasis is placed on the applications of EPS in various large-scale commercial and industrial sectors.
... En la Tabla 1, se muestra la cantidad del exopolisacárido extraído de A. vinelandii, el valor 0.24 g/L fue estadísticamente diferente al valor de 0.09g/L de P. polymyxa,, la concentración de estos polímeros fueron inferiores a lo reportado en otros géneros de bacterias fijadores de N2, de ambientes salinos como: Volcaniella eurhialina. H96: con 1.3 g/L (Calvo et al., 2003), ...
Resumen Los géneros de bacterias fijadoras de N2 para realizar esta actividad generan un exo polisacárido que protege a la enzima nitrogenasa, estos polisacáridos son compuestos de elevado peso de molecular, que pueden ser extraído y usado como absorbente para líquidos solubles e insolubles. El objetivo de este trabajo fue analizar en Azotobacter vinelandii y Paenibacillus polymyxa las condiciones para inducir la máxima producción de exo polisacáridos. Con ese propósito ambos géneros se crecieron en medios de cultivo sin N (nitrógeno) combinado, para medir la cantidad de exo polisacáridos generado a la par con el número de células generadas en esa condición Los resultados indican que las condiciones aplicadas: medio de cultivo A. vinelandii genero más exo polisacáridos que P. polymyxa, por lo que se encontrar la composición del medio de cultivo, además de la temperatura y tiempo para optimizar esa síntesis para el uso biotecnológico. Palabras clave. A. vinelandii, P. polymyxa, medio libre N, polisacáridos. Introducción Los géneros de bacterias que fijan N2 molecular sintetizan exo polisacáridos para proteger la actividad de la enzima (Matas, 2006); lo que hace que las colonias de estas géneros sean mucosas en medio de cultivo sólido, o bien, por un aumento en la viscosidad e incluso en
... Polysaccharides produced by Halomonas eurihalina [4], H. maura [5] have been described and well characterized. Aqueous solution of EPS synthesized by H. eurihalina has been reported to jellify at acidic pH, while mauran, an anionic, sulfated EPS with high uronic acid composition produced by H. maura are being used for different biotechnological purposes [6,7]. The extracellular polysaccharide production by H. ventosae, H. anticariensis and H. almeriensis [8] has been optimized with a view to identify their components and physico-chemical properties [9]. ...
A moderately halophilic bacterium, Halomonas xianhensis SUR308 (GenBank Accession No. KJ933394) was isolated from multi-pond solar salterns of Odisha, India. Exopolysaccharide (EPS) production by this strain in malt extract yeast extract (MY) medium has been optimized under batch culture system. Among the different media tested, MY medium showed an EPS production of 2.55 g/L, which increased to 2.85 g/L under optimized aeration. An initial pH of 7.5 and incubation temperature of 32 °C were found to be most suitable for EPS production by the isolate under aerobic condition. An EPS production of 3.85 g/L was achieved when the growth medium was supplemented with 2.5% NaCl. Glucose was the most favourable carbon source for EPS production and maximum production (5.70 g/L) was recorded with 3% glucose. However, growth as well as production of EPS was remarkably affected when the growth medium was supplemented with hydrocarbons as sole source of carbon. Among different nitrogen sources, casein hydrolysate at 0.5% level was proved to be the best for EPS production and an initial inoculum dose of 7% (v/v) enhanced the EPS production to 7.78 g/L, while the divalent metal ions were in general toxic to growth and EPS production, EPS synthesis by SUR308 was enhanced with Cr (VI) supplementation.
... Cyanobacterium aphanotece (Oren 2010). Mauran, the extracellular polysaccharide produced by Halomonas maura, forms highly viscous aqueous solutions (Bouchotroch et al. 2000;Arias et al. 2003;Quesada et al. 2004), while the EPS produced by Halomonas eurihalina forms a gel at acidic pH which has a high emulsifying capacity (Quesada et al. 1993;Calvo et al. 1995Calvo et al. , 1998Bejar et al. 1996Bejar et al. , 1998. The EPS produced by H. ventosae, H. anticariensis, Idiomarina fontislapidosi, I. ramblicola and Alteromonas hispanica have significant emulsifying properties (Mata et al. 2006(Mata et al. , 2008 and the EPS produced by Salipiger mucosus contains a substantial quantity of fucose. ...
A moderately halophilic bacterium, Halomonas xianhensis SUR308 (Genbank Accession No. KJ933394) was isolated from a multi-pond solar saltern at Surala, Ganjam district, Odisha, India. The isolate produced a significant amount (7.87 g l(-1)) of extracellular polysaccharides (EPS) when grown in malt extract-yeast extract medium supplemented with 2.5% NaCl, 0.5% casein hydrolysate and 3% glucose. The EPS was isolated and purified following the conventional method of precipitation and dialysis. Chromatographic analysis (paper, GC and GC-MS) of the hydrolyzed EPS confirmed its heteropolymeric nature and showed that it is composed mainly of glucose (45.74 mol%), galactose (33.67 mol %) and mannose (17.83 mol%). Fourier-transform infrared spectroscopy indicated the presence of methylene and carboxyl groups as characteristic functional groups. In addition, its proton nuclear magnetic resonance spectrum revealed functional groups specific for extracellular polysaccharides. X-ray diffraction analysis revealed the amorphous nature (CIxrd, 0.56) of the EPS. It was thermostable up to 250°C and displayed pseudoplastic rheology and remarkable stability against pH and salts. These unique properties of the EPS produced by H. xianhensis indicate its potential to act as an agent for detoxification, emulsification and diverse biological activities.
... Beyond the solution properties, they may also present interesting biological activities, namely those composed of l-fucose, l-rhamnose or uronic acids residues. Such functional properties are the driving force for the search of new bacterial polysaccharides with potential to be used on specific applications [6,11]. ...
... For example, the EPSs produced by the 19 strains of H. eurihalina differ from one another [11]. Indeed, only the EPS of the strain F2-7 of H. eurihalina form gels at acid pH [43,44]. ...
... Sulphated EPSs are polymers of great interest in medicine since they have a number of bioactive properties as anticoagulants, antiproliferative agents and antivirals among others [47][48][49]. Phosphate groups, which have also been observed in other EPSs [8,14,16,17,43,50], could confer important properties on them because they are essential to the activation of lymphocytes [51,52] and in some antitumoural actions [53]. Finally, haloglycan could be a source of fucose, as reported for the EPSs from Klebsiella pneumoniae and Clavibacter michiganensis [54] and Salipiger mucosus [16]. ...
We have conducted a thorough study of the exopolysaccharide (EPS) produced by strain HK30 of Halomonas stenophila, which we have named haloglycan. This strain was chosen during an ongoing research program aimed at finding novel exopolysaccharide-producing halophilic bacteria in unexplored hypersaline habitats. Strain HK30 was isolated from a saline-wetland in Brikcha (Morocco) and identified as belonging to the species Halomonas stenophila. It produced EPS mainly during the exponential growth phase and to a lesser extent during the stationary phase. Culture parameters influenced both bacterial growth and EPS production, EPS yield always being directly related to the quantity of biomass. Under optimum culture conditions strain HK30 produced 3.89 gram of EPS per litre of medium. The polymer was a sulphated heteropolysaccharide composed of two fractions, with molecular masses of 8.2×10(4) and 1.4×10(6). The crude EPS contained 44±0.1% w/w carbohydrates and the following monosaccharide composition: glucose (24±1.73), glucuronic acid (7.5±0.37), mannose (5.5±0.17), fucose (4.5±0.36), galactose (1.2±0.17) and rhamnose (1±0.05) (%, w/w). It produced solutions of high viscosity and pseudoplastic behaviour that showed interesting flocculating and emulsifying activities and was also involved in forming biofilm.
... The in situ production of xanthan-like polysaccharide in the oil-bearing strata has been suggested as a means of aiding tertiary oil recovery (Wells, 1977). Volcaniella eurihalina F2–7 is known to synthesize an exopolysaccharide, the rheological properties of which are stable to pH and inorganic salts, which makes it a suitable candidate for enhanced oil recovery (Calvo, Ferrer, Martínez-Checa, Béjar, & Quesada, 1995). An exopolysaccharide produced by E. cloaceae has been reported to have good viscosity even at high temperature , which makes it a probable candidate for microbial enhanced oil recovery (Iyer, Mody, & Jha, 2005a). ...
Extracellular polysaccharides (EPSs) produced by microorganisms are a complex mixture of biopolymers primarily consisting of polysaccharides, as well as proteins, nucleic acids, lipids, and humic substances. Microbial polysaccharides are multifunctional and can be divided into intracellular polysaccharides, structural polysaccharides, and extracellular polysaccharides or exopolysaccharides. Recent advances in biological techniques allow high levels of polysaccharides of interest to be produced in vitro. Biotechnology is a powerful tool to obtain polysaccharides from a variety of marine microorganisms, by controlling the growth conditions in a bioreactor while tailoring the production of biologically active compounds. The aim of this chapter is to give an overview of current knowledge on extracellular polysaccharides producing marine bacteria isolated from marine environment.
... The interest in microbial exopolysaccharides is constantly expanding because of their specific rheological, chemical, biological and pharmaceuti cal properties, and their wide-range applications in fields of industry and medicine. Exopolysaccha rides are synthesized by microorganisms of various taxonomy (bacteria, fungi, yeast) (Calvo et al., 1995;Schuster et al., 1993;Sarkar et al., 1986;Igochi et al., 1990;Adami and Cavazzoni, 1990). Yeast polysaccharides can be used to obtain glucan, mannan and glucomannan (Sarkar et al., 1986;Elinov et al., 1979;Chiura et al., 1982). ...
Exopolysaccharides from the lactose-negative yeast Rhodotorula glutinis 16P were synthesized by co-cultivation with the yeast Kluyveromyces lactis MP11 or with the homofermentative lactic acid bacteria Lactobacillus helveticus 9A in a cheese whey ultrafiltrate. Exopolysaccharides were produced by lactose hydrolysis, performed by two pathways: with β-galactosidase from Kluyveromyces lactis MP11 which assimilates glucose and galactose; with β-galactosidase and Lactobacillus helveticus 9A which uses lactic acid. By growing the two mixed cultures maximum yield was obtained as follows: 11.4 g/l and 15.8 g/l, respectively. Structural units of the carbohydrate composition of the two polymers are mannose (72.4-63.5%), glucose (2.0-15.9%), galactose (25.3-19.8%) and xylose (3.6-4.3%). Mannose dominated in the polysaccharide compositions.
... Se coincide con Bouchotroch et al. (2001), Arias et al. (2003), Martínez et al. (2004) y Mata (2006), quienes demostraron la presencia de bacterias productoras de EPS en ambientes hipersalinos, identificando especies de Halomonas, Idiomarina, Alteromonas, Salipiger y Palleronia. A su vez, el valor máximo de 1,2 gL -1 de EPS producidos por la bacteria M5l0 -1 C 1 después de 4 días se acerca a 1,3 gL -1 reportado por Calvo et al. (2003) para H. eurihalina H96; sin embargo, es inferior a 3,8 gL -1 alcanzado por H. maura S-30, después de 5 días de incubación (Arias et al., 2003). El 70,6 % de los EPS producidos por las bacterias aisladas de agua presentó actividad emulgente (Tabla 1). ...
... En general, el 62,5 % de los EPS obtenidos presentó actividad emulgente, correspondiendo al 10,8 % de las bacterias halófilas nativas, las mismas que fueron seleccionadas para la fase experimental del trabajo. Se coincide con Bouchotroch et al. (2001), Calvo et al. (2003) y Martínez et al. (2004, quienes determinaron que el EPS H96 producido por H. eurihalina tiene actividad emulsificante sobre hidrocarburos y otras sustancias lipídicas, así como el maurano de H. maura S-30 tiene propiedades viscosizantes y emulsificantes, muy similares al xantano, que es el agente de este tipo más ampliamente utilizado en la industria de alimentos. Según Mata (2006) algunos EPS provocan una disminución no tan marcada de la tensión superficial de las interfases y fundamentalmente estabilizan las emulsiones al aumentar la viscosidad y reducir la movilidad de las gotículas, por lo que son considerados bioemulgentes estabilizadores. ...
The microbial exopolysaccharide with emulsifying properties are an alternative to polymers and chemicals from algae and plants. Its production in molasses as carbon source lowers costs and generates added value to this byproduct of the sugar industry, so the aim of this study was to determine the performance and productivity of EPS emulsifiers by native halophilic bacteria in 20, 30 and 40 gL-1 of molasses. In MY synthetic medium with 5 % w/v of salts, 138 isolates of bacteria obtained from soil samples of salt water and in the districts of San Jose and Santa Rosa, in Lambayeque. In 10.8 % of these gummy colony forming bacteria and grown on glucose as carbon source EPS recovered whose maximum values of the mixtures in water emulsion - oil phase were 63.3 and 56.6 % after 1 and 24 hours, respectively. The M5 bacteria identified as Halomonas C1 10-1 sp. M5 EPS synthesized emulsifiers molasses broth, reaching yields Yp/s of 0.296 gg-1 and 0.200 gg-1 with 20 and 30 gL-1 of molasses respectively, a productivity of 0.016 and 0.017 gL-1 h -1 , not differing significantly between them. With 10 gL-1 glucose was reached Yp/s of 0.171 gg-1 and a productivity of 0.018 gL-1 h -1 . It was shown that the EPS produced native halophilic bacteria utilizing molasses emulsifiers as carbon source.
