scholarly journals Structural and Physicochemical Characterization of Rhamnolipids produced by Pseudomonas aeruginosa P6

AMB Express ◽  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ghadir S. El-Housseiny ◽  
Khaled M. Aboshanab ◽  
Mohammad M. Aboulwafa ◽  
Nadia A. Hassouna
Keyword(s):  
Oil Recovery ◽  
High Performance ◽  
Physicochemical Characterization ◽  
Resonance Spectroscopy ◽  
Complex Environments ◽  
Potential Applications ◽  
Thin Layer Chromatographic Analysis ◽  
Wild Type Form ◽  
Excellent Stability

Abstract Rhamnolipids are important biosurfactants for application in bioremediation, enhanced oil recovery, pharmaceutical, and detergent industry. In this study, rhamnolipids extracted from P. aeruginosa P6 were characterized to determine their potential fields of application. Thin-layer chromatographic analysis of the produced rhamnolipids indicated the production of two homologues: mono- and di-rhamnolipids, whose structures were verified by 1H and 13C nuclear magnetic resonance spectroscopy. Additionally, high performance liquid chromatography-mass spectrometry identified seven different rhamnolipid congeners, of which a significantly high proportion was di-rhamnolipids reaching 80.16%. Rha-Rha-C10-C10 was confirmed as the principal compound of the rhamnolipid mixture (24.30%). The rhamnolipids were capable of lowering surface tension of water to 36 mN/m at a critical micelle concentration of 0.2 g/L, and exhibited a great emulsifying activity (E24 = 63%). In addition, they showed excellent stability at pH ranges 4–8, NaCl concentrations up to 9% (w/v) and temperatures ranging from 20 to 100 °C and even after autoclaving. These results suggest that rhamnolipids, produced by P. aeruginosa P6 using the cheap substrate glycerol, are propitious for biotechnology use in extreme and complex environments, like oil reservoirs and hydrocarbon contaminated soil. Moreover, P. aeruginosa P6 may be considered, in its wild type form, as a promising industrial producer of di-RLs, which have superior characteristics for potential applications and offer outstanding commercial benefits.

scholarly journals Physicochemical characterization of the pulp oil of bacuri Attalea phalerata Mart. ex Spreng. (Arecaceae)

2020 ◽  
Vol 21 (3) ◽  
pp. 1-11
Author(s):  
Michelle Cardoso Coimbra ◽  
Débora Maria Moreno Luzia ◽  
Neuza Jorge
Keyword(s):  
Fatty Acids ◽  
Gas Chromatography ◽  
Refractive Index ◽  
Fatty Acid ◽  
Potassium Hydroxide ◽  
High Performance ◽  
Physicochemical Characterization ◽  
Physicochemical Characteristics ◽  
Total Phenolic

The aim of the study was to characterize the pulp oil of bacuri Attalea phalerata Mart. ex Spreng. (Arecaceae) according to official analytical methods. Total phenolic and carotenoids contents were evaluated by spectrophotometry, and tocopherols composition by high-performance liquid chromatography. The fatty acid profile was obtained through gas chromatography from samples transesterified with potassium hydroxide in methanol and n-hexane. According to the proximate composition, bacuri pulp contained 41.5 % carbohydrates and 39.2 % lipids. Regarding its physicochemical properties, the oil showed a free fatty acids content of 0.7 %, a peroxide value of 1.4 meq/kg, a refractive index of 1.463, an iodine number of 84.3 g I2/100 g, a saponification number of 193.5 mg KOH/g, an unsaponifiable matter of 0.5 %, and 48.7 h of oxidative stability. Total phenolic, carotenoids, and tocopherols contents recorded values of 2.4 mg GAE/g, 243.0 µg/g, and 86.8 mg/kg, respectively. The bacuri oil showed a fatty acid composition similar to olive oil and a high percentage of unsaturation, finding 67.3 % of monounsaturated acids, and 11.3 % of polyunsaturated acids. The main fatty acids were oleic (67.3 %), palmitic (13.3 %), and linoleic (10.5 %). Due to its physicochemical characteristics, bacuri oil has a great potential to be used in food preparations, such as salad oil or in margarine formulation.

scholarly journals Enhancement of Solubilization and Biodegradation of Polyaromatic Hydrocarbons by the Bioemulsifier Alasan

1999 ◽  
Vol 65 (6) ◽  
pp. 2697-2702 ◽  
Author(s):  
T. Barkay ◽  
S. Navon-Venezia ◽  
E. Z. Ron ◽  
E. Rosenberg
Keyword(s):  
Polyaromatic Hydrocarbons ◽  
Physicochemical Characterization ◽  
Aqueous Solubility ◽  
Physical Interaction ◽  
Hydrophobic Compounds ◽  
Enhanced Solubility ◽  
Potential Applications ◽  
Hydrophobic Nature ◽  
Aqueous Solubilities

ABSTRACT Alasan, a high-molecular-weight bioemulsifier complex of an anionic polysaccharide and proteins that is produced by Acinetobacter radioresistens KA53 (S. Navon-Venezia, Z. Zosim, A. Gottlieb, R. Legmann, S. Carmeli, E. Z. Ron, and E. Rosenberg, Appl. Environ. Microbiol. 61:3240–3244, 1995), enhanced the aqueous solubility and biodegradation rates of polyaromatic hydrocarbons (PAHs). In the presence of 500 μg of alasan ml−1, the apparent aqueous solubilities of phenanthrene, fluoranthene, and pyrene were increased 6.6-, 25.7-, and 19.8-fold, respectively. Physicochemical characterization of the solubilization activity suggested that alasan solubilizes PAHs by a physical interaction, most likely of a hydrophobic nature, and that this interaction is slowly reversible. Moreover, the increase in apparent aqueous solubility of PAHs does not depend on the conformation of alasan and is not affected by the formation of multimolecular aggregates of alasan above its saturation concentration. The presence of alasan more than doubled the rate of [14C]fluoranthene mineralization and significantly increased the rate of [14C]phenanthrene mineralization bySphingomonas paucimobilis EPA505. The results suggest that alasan-enhanced solubility of hydrophobic compounds has potential applications in bioremediation.

scholarly journals Characterization of Exopolysaccharides Produced by Rhizobia Species

2015 ◽  
Vol 39 (6) ◽  
pp. 1566-1575 ◽  
Author(s):  
Tereza Cristina Luque Castellane ◽  
Alda Maria Machado Bueno Otoboni ◽  
Eliana Gertrudes de Macedo Lemos
Keyword(s):  
High Performance ◽  
Biological Properties ◽  
Reversed Phase ◽  
The Past ◽  
Structure And Dynamics ◽  
Key Factor ◽  
Reactive Groups ◽  
Potential Applications ◽  
Species Specific

ABSTRACT Increasing attention has been given, over the past decades, to the production of exopolysaccharides (EPS) from rhizobia, due to their various biotechnological applications. Overall characterization of biopolymers involves evaluation of their chemical, physical, and biological properties; this evaluation is a key factor in understanding their behavior in different environments, which enables researchers to foresee their potential applications. Our focus was to study the EPS produced by Mesorhizobium huakuii LMG14107, M. loti LMG6125, M. plurifarium LMG11892,Rhizobium giardini bv. giardiniH152T, R. mongolense LMG19141, andSinorhizobium (= Ensifer)kostiense LMG19227 in a RDM medium with glycerol as a carbon source. These biopolymers were isolated and characterized by reversed-phase high-performance liquid chromatography (RP-HPLC), Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR) spectroscopies. Maximum exopolysaccharide production was 3.10, 2.72, and 2.50 g L-1for the strains LMG6125, LMG19227, and LMG19141, respectively. The purified EPS revealed prominent functional reactive groups, such as hydroxyl and carboxylic, which correspond to a typical heteropolysaccharide. The EPS are composed primarily of galactose and glucose. Minor components found were rhamnose, glucuronic acid, and galacturonic acid. Indeed, from the results of techniques applied in this study, it can be noted that the EPS are species-specific heteropolysaccharide polymers composed of common sugars that are substituted by non-carbohydrate moieties. In addition, analysis of these results indicates that rhizobial EPS can be classified into five groups based on ester type, as determined from the 13C NMR spectra. Knowledge of the EPS composition now facilitates further investigations relating polysaccharide structure and dynamics to rheological properties.

scholarly journals Physicochemical Characterization of Thermally Treated Chitosans and Chitosans Obtained by Alkaline Deacetylation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ana Maria de Oliveira ◽  
Telma Teixeira Franco ◽  
Enio Nazaré de Oliveira Junior
Keyword(s):  
Thermal Treatment ◽  
Kinematic Viscosity ◽  
Molar Mass ◽  
Physicochemical Characterization ◽  
Gel Permeation Chromatography ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Gel Permeation ◽  
Thermal Depolymerization

The thermal depolymerization of chitosan and alkaline deacetylation of chitin were characterized by measurement of viscosity, gel permeation chromatography (GPC), potentiometric titration (PT), and proton nuclear magnetic resonance spectroscopy (H1NMR). The depolymerization rates (DR) measured by kinematic viscosity (KV), apparent viscosity (AV), and GPC (Mw) until 4 h of treatment wereDRKV=21.9,DRAV=25.5, andDRMw=23.3% h-1and for 5 to 10 h of treatment they decreased slowly to produce ofDRKV=0.545,DRAV=0.248, andDRMw=1.11% h-1. The mole fraction of N-acetylglucosamine residuesFAof chitosans was not modified after 10 h of thermal treatment at 100°C. The initialFAvalues of chitosan without any treatment wereFAPT=0.21andFAHNMR1=0.22and of chitosan treated for 10 h wereFAPT=0.27andFAHNMR1=0.22. The variables used to characterize the depolymerization process showed a good correlation. Six hours of thermal treatment as sufficient to obtain chitosans with a molar mass 90% smaller than that of the control chitosan without treatment.

scholarly journals Development and Physicochemical Characterization of Desonide-Loaded Nanocapsule Suspensions

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
M. B. Antonow ◽  
R. Lorenzoni ◽  
G. M. Barbosa ◽  
A. F. Ourique ◽  
P. Gomes ◽  
...  
Keyword(s):  
Particle Size ◽  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Release Kinetics ◽  
Physicochemical Characterization ◽  
Eudragit S100 ◽  
Franz Diffusion Cells ◽  
Negative Zeta Potential

Desonide is a topical corticosteroid that has been used for more than 30 years; however, its prolonged use can induce several side effects, affecting dermis and epidermis. The present work consists of development desonide-loaded nanocapsule suspensions (D-NC) using different polymers (Eudragit S100® or Eudragit L100®) and desonide-loaded lipid-core nanocapsules (D-LNC). They were formulated by interfacial deposition using the preformed polymer method and all formulations showed negative zeta potential and adequate nanotechnological characteristics (particle size 161–202 nm, polydispersity index < 0.20). Simple and sensitive methods using high-performance liquid chromatography (HPLC) were developed to quantify desonide in LNC and to study its release kinetics. The method was linear, specific, precise, and exact and therefore can be applied in quantification of D-NC and D-LNC. We evaluatedin vitromethods for drug release (dissolution, Franz diffusion cells, and dialysis sac) and we use mathematical models (monoexponential, biexponential, and Korsmeyer-Peppas) to show release kinetics from this system.

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