scholarly journals Characterization and Biotechnological Potential of Intracellular Polyhydroxybutyrate by Stigeoclonium sp. B23 Using Cassava Peel as Carbon Source

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 687
Author(s):  
Murilo Moraes Mourão ◽  
Luciana Pereira Xavier ◽  
Ralph Urbatzka ◽  
Lucas Barbosa Figueiroa ◽  
Carlos Emmerson Ferreira da Costa ◽  
...  

The possibility of utilizing lignocellulosic agro-industrial waste products such as cassava peel hydrolysate (CPH) as carbon sources for polyhydroxybutyrate (PHB) biosynthesis and characterization by Amazonian microalga Stigeoclonium sp. B23. was investigated. Cassava peel was hydrolyzed to reducing sugars to obtain increased glucose content with 2.56 ± 0.07 mmol/L. Prior to obtaining PHB, Stigeoclonium sp. B23 was grown in BG-11 for characterization and Z8 media for evaluation of PHB nanoparticles’ cytotoxicity in zebrafish embryos. As results, microalga produced the highest amount of dry weight of PHB with 12.16 ± 1.28 (%) in modified Z8 medium, and PHB nanoparticles exerted some toxicity on zebrafish embryos at concentrations of 6.25–100 µg/mL, increased mortality (<35%) and lethality indicators as lack of somite formation (<25%), non-detachment of tail, and lack of heartbeat (both <15%). Characterization of PHB by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimeter (DSC), and thermogravimetry (TGA) analysis revealed the polymer obtained from CPH cultivation to be morphologically, thermally, physically, and biologically acceptable and promising for its use as a biomaterial and confirmed the structure of the polymer as PHB. The findings revealed that microalgal PHB from Stigeoclonium sp. B23 was a promising and biologically feasible new option with high commercial value, potential for biomaterial applications, and also suggested the use of cassava peel as an alternative renewable resource of carbon for PHB biosynthesis and the non-use of agro-industrial waste and dumping concerns.

Author(s):  
M O Oyewale

The mycelial dry weight and dinitrosalicylic acid (D.N.S.A.) method was used to determine growth and amylase production by Aspergillus flavus grown on different carbon sources. Growth of the fungus was determined at 24 h intervals over a period of six days by the dry mycelial weight methods, while the amylase activity in the culture filtrates of A. flavus was determined by the D.N.S.A method. A total of 45 samples were prepared to determine growth and amylase activity of Aspergillus flavus grown on different carbon sources. The concentration of the various carbon sources ranges between 0.4 to 2% W/V. Duncan’s multiple range test was used to determine the level of significance of the different carbon sources for effective growth and amylase production by Aspergillus flavus. Aspergillus flavus demonstrated the capability to produce significant growth and amylase activities in the medium containing soluble starch, sorghum and cassava peel as sole carbon source. The amount of mycelial dry weight produced from soluble starch, sorghum and cassava peel is significantly higher than those produced from other carbon sources. The data revealed that there is a correlation between growth and amylase production by Aspergillus flavus. The available data from this study showed that soluble starch is the best carbon source for optimum growth and amylase production by A flavus while sorghum and cassava peel are close substitute for optimum growth and amylase production by Aspergillus flavus. Keywords: Growth, amylase activity and Aspergillus flavus


Author(s):  
Sudha Sree

Abstract: Polysaccharides are important potent molecules with their structural and compositional complexity which led to wide range of applications in various industries. The exopolysaccharides of microbial origin are released in response to extreme environmental conditions for the purpose of survival. The present study focuses on the isolation of exopolysaccharide producing bacteria from the soil sample and oil contaminated soil sample. Screening for the EPS production by the isolates is determined by the dry weight determination of precipitates of EPS and quantitative estimation of glucose content of EPS by PhenolSulphuric acid method. In the present study, out of 5 bacterial isolates isolated on screening, Lactobacillus sps and Pseudomonas sps. isolates produced the precipitates of EPS whose dry weight was determined to be 0.09g and 0.17g respectively. Further, glucose concentration of EPS was quantitatively determined. The glucose content of Lactobacillus sps. isolate was 0.1125mg/ml and Pseudomonas sps. isolate is 0.2875mg/ml. The EPS producing isolates were further grown in the presence of carbon sources like Glucose, Lactose, Maltose and Sucrose to determine the best utilizable carbon for their growth. The most utilizable carbon source for maximum growth of EPS producing isolates was determined to be sucrose with 2% concentration. All the 5 bacterial isolates were screened for their ability of antibiotic resistance. The EPS producing isolates, Lactobacillus sps, Pseudomonas sps were found to be resistant towards all the antimicrobial agents owing to the presence of EPS protective layer around their cell wall than non-EPS producing isolates. Keywords: Exopolysaccharide, Screening, Carbon sources, Antibiotic resistance.


Author(s):  
G. S. Zakharova ◽  
E. Thauer ◽  
A. N. Enyashin ◽  
L. F. Deeg ◽  
Q. Zhu ◽  
...  

AbstractThe potential battery electrode material V2O3/C has been prepared using a sol–gel thermolysis technique, employing vanadyl hydroxide as precursor and different organic acids as both chelating agents and carbon sources. Composition and morphology of resultant materials were characterized by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopies, physical sorption, and elemental analysis. Stability and electronic properties of model composites with chemically and physically integrated carbon were studied by means of quantum-chemical calculations. All fabricated composites are hierarchically structured and consist of carbon-covered microparticles assembled of polyhedral V2O3 nanograins with intrusions of amorphous carbon at the grain boundaries. Such V2O3/C phase separation is thermodynamically favored while formation of vanadium (oxy)carbides or heavily doped V2O3 is highly unlikely. When used as anode for lithium-ion batteries, the nanocomposite V2O3/C fabricated with citric acid exhibits superior electrochemical performance with an excellent cycle stability and a specific charge capacity of 335 mAh g−1 in cycle 95 at 100 mA g−1. We also find that the used carbon source has only minor effects on the materials’ electrochemical performance.


1993 ◽  
Vol 50 (7) ◽  
pp. 300-303
Author(s):  
Yu. L. Belousov ◽  
M. V. Pushkareva

2013 ◽  
Vol 2013 ◽  
pp. 1-4
Author(s):  
Mihail Doynov ◽  
Tsvetan Dimitrov ◽  
Maria Kokkori

The synthesis of arsenic-free ceramics from industrial waste is studied. Samples of waste containing siliceous material passed the exploitation leap-guard layer shift reactor whose main oxide is -Al2O3and, with the addition of natural raw materials and pure oxide, arsenic-free ceramics were synthesized with thermal and electrical properties related to the main phase of spinel group minerals; solid solutions were also formed in the process of synthesis. Insulating properties were established by successive heating and cooling of the specimen for six cycles. Electrical insulating properties were established by the method of resistance to arcing. The relative density was determined by hydrostatic method and diffusion lines of molecules at the main phase were characterized by X-ray diffraction analysis. The experimental procedures followed in this study allowed mixing on a molecular level due to the small dimensions of the crystallite which in turn explains the relatively high density.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Sarath Chandra K ◽  
Krishnaiah S ◽  
Kibebe Sahile

Industrialization is the key to the growth of any country’s economy. However, on the other hand, the production of industrial waste is increasing enormously, which adversely impacts the environment and natural resources. Red mud is also a widespread industrial waste produced during aluminium extraction from bauxite ore in Bayer’s process. Red mud is a highly alkaline material that creates a massive environmental threat in nature. To reduce the impact of this solid waste material, the ideal method is to use it in construction works with appropriate stabilization. This study envisages the strength properties of red mud with fly ash and cement to use it as a road construction material in the subgrade. The influence of fly ash and cement on improving the strength properties of red mud was studied in detail by replacing red mud with 10%, 20%, and 30% with fly ash and 1%, 3%, and 5% of cement to its dry weight. The CBR (California bearing ratio) value was increased from 1.58% to 11.6% by stabilizing red mud with fly ash and cement, which can be used as a road construction material. The UCS (unconfined compressive strength) of red mud was increased from 825 kPa to 2340 kPa upon curing for 28 days with the right mix of fly ash and cement. Along with the strength properties, the chemical analysis of leachate for the best suitable mix was performed according to the TCLP method to understand the hazardous materials present in the red mud when it is injected as ground material. Both strength properties and the leachate characteristics prove that the red mud with suitable fly ash and cement is an excellent material in road constructions.


2021 ◽  
Vol 12 (5) ◽  
pp. 6580-6588

Dicalcium phosphate dihydrate (DCPD) nanoparticles, also known as brushite, are considered an important bioceramic compound. In this study, brushite was prepared from Moroccan phosphogypsum (PG) using a new sol-gel method. A two-step technique undergoes the synthesis of brushite, the preparation of anhydrite from PG followed by adding phosphoric acid in the presence of sodium hydroxide. The morphology, the chemical composition, and the crystallites size were obtained using Scanning Electron Microscopy (SEM-EDAX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR), respectively. According to the Debye-Scherrer equation, these characterization methods indicated that the synthesized brushite was highly pure according to the Ca/P ratio of 1.14 and an average crystallites size estimated at 66 nm. These results proved that the brushite was successfully synthesized from Moroccan phosphogypsum.


The cell-wall structure of the red alga Rhodymenia palmata has been examined by the methods of X -ray diffraction analysis and electron microscopy, including ultra-thin sectioning. The cell wall is shown to consist of numerous lamellae each of which is made up of unoriented, crystalline microfibrils embedded in an amorphous matrix of other cell-wall constituents. The material can be stretched reversibly up to 100% when wet, and the stretching induces orientation of the microfibrils. The ‘∝ cellulose' fraction, which accounts for only 2 to 7 % of the original dry weight, was isolated chemically and was analyzed by means of hydrolysis and paper chromatographic separation of the resulting sugars, and it was found to be composed of approximately equal quantities of glucose and xylose residues. Chemical treatment of the cell wall was found to cause considerable variations in the X -ray diagrams, which are discussed. It is concluded that the microfibrils contain both glucose and xylose residues in approximately equal proportions and that chemical treatment in this case causes changes in crystallinity of the structural component of the wall. The importance of these findings for the meaning of the term cellulose is discussed. The X -ray diagram of older fronds was found to be complicated by the occurrence of extra rings due to the presence of floridean starch, and the highly elastic properties of the thallus enabled the diagrams of the starch and the cell wall to be separated.


2017 ◽  
Vol 2 (2) ◽  
pp. 174
Author(s):  
Rogozhnikov D.A. ◽  
Dizer O.A. ◽  
Shoppert A.A.

<p>Thermodynamic and kinetic features studies of polymetallic sulfide industrial waste nitric acid leaching were carried out. Elemental and phase composition of investigated raw material were studied with X-ray diffraction and electron microscopy methods. Calculations of the Gibbs energy change for the likely reactions of sulfide minerals with nitric acid were performed. In order to determine the most probable conditions of the sulfide industrial waste leaching in nitric acid, as well as the mutual influence of the produced pulp components on the performance of the process, the kinetics evaluation of multicomponent sulfide industrial waste in a nitric medium was studied using mathematical methods.</p>


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