Production and optimization of certain growth parameters for an exopolysaccharide from Azotobacter vinelandii MTCC 2460 isolated from a plant rhizosphere

Abstract This study aimed to evaluate the growth, respiratory activity, and biodegradation of chlorpyrifos in cultures of Azotobacter vinelandii ATCC 12837. A strategy based on the modification of culture media and aeration conditions was carried out to increase the cell concentration of A. vinelandii , in order to favor and determine its tolerance to chlorpyrifos and its degradation ability. The culture in shaken flasks, using sucrose as a carbon source, significantly improved the growth compared to media with mannitol. When the strain was cultivated under oxygen-limited (5.5, 11.25 mmol L- 1 h- 1 ) and no-oxygen-limited conditions (22 mmol L -1 h -1 ), the growth parameters were not affected. In cultures in a liquid medium with chlorpyrifos, the bacteria tolerated a high pesticide concentration (500 ppm) and the growth parameters were improved even under conditions with a reduced carbon source (sucrose 2 g L -1 ). The strain degraded 99.6 % of chlorpyrifos at 60 h of cultivation, in co-metabolism with sucrose; notably, A. vinelandii ATCC 12837 reduced by 50% the initial pesticide concentration in only 6 h (DT 50 ).

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Growth, respiratory activity and chlorpyrifos biodegradation in cultures of Azotobacter vinelandii ATCC 12837

AMB Express ◽

10.1186/s13568-021-01339-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Victoria Conde-Avila ◽

Carlos Peña ◽

Beatriz Pérez-Armendáriz ◽

Octavio Loera ◽

Carmen Martínez Valenzuela ◽

...

Keyword(s):

Carbon Source ◽

Liquid Medium ◽

Respiratory Activity ◽

Azotobacter Vinelandii ◽

Cell Concentration ◽

Culture Media ◽

Growth Parameters ◽

Pesticide Concentration ◽

Aeration Conditions ◽

Degradation Ability

AbstractThis study aimed to evaluate the growth, respiratory activity, and biodegradation of chlorpyrifos in cultures of Azotobacter vinelandii ATCC 12837. A strategy based on the modification of culture media and aeration conditions was carried out to increase the cell concentration of A. vinelandii, in order to favor and determine its tolerance to chlorpyrifos and its degradation ability. The culture in shaken flasks, using sucrose as a carbon source, significantly improved the growth compared to media with mannitol. When the strain was cultivated under oxygen-limited (5.5, 11.25 mmol L−1 h−1) and no-oxygen-limited conditions (22 mmol L−1 h−1), the growth parameters were not affected. In cultures in a liquid medium with chlorpyrifos, the bacteria tolerated a high pesticide concentration (500 ppm) and the growth parameters were improved even under conditions with a reduced carbon source (sucrose 2 g L−1). The strain degraded 99.6% of chlorpyrifos at 60 h of cultivation, in co-metabolism with sucrose; notably, A. vinelandii ATCC 12837 reduced by 50% the initial pesticide concentration in only 6 h (DT50). Graphical Abstract

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RESPONSE OF A LOCAL AND SOME EXOTIC MUNGBEAN VARIETIES TO BIO- AND MINERAL FERTILIZATION

Acta Agronomica Hungarica ◽

10.1556/aagr.49.2001.3.6 ◽

2001 ◽

Vol 49 (3) ◽

pp. 251-259 ◽

Cited By ~ 2

Author(s):

M. F. El-Kramany ◽

A. A. Bahr ◽

A. M. Gomaa

Keyword(s):

Seed Yield ◽

Harvest Index ◽

Phosphorus Content ◽

Azotobacter Vinelandii ◽

Growth Parameters ◽

Research Centre ◽

Mineral Fertilizers ◽

Mineral Fertilization ◽

Bradyrhizobium Sp ◽

Biological Yield

A pot trial was carried out in the greenhouse of the National Research Centre during the summer season of 1999 to investigate the combined impact of Bradyrhizobium sp. (vigna) and Azotobacter vinelandii in the presence of various doses of chemical fertilizers, i.e. 25%, 50% and 100% of the recommended dose of NPK, on nodulation, growth parameters, seed yield and its components, and seed contents of protein, phosphorus and potassium of a local (Kawmy-1) and three exotic (VC-4, VC-9 and King) varieties of mungbean. The results indicated that there were no significant differences between the different varieties for nodule number per plant, while significant variations were obtained between both varieties and biofertilization treatments. The plants of the Kawmy-1 variety gave the shortest period of growth, the highest number of pods per plant and the highest values of harvest index and seed protein content. The King variety had the longest period of growth and the highest values for number of branches, seed yield, biological yield, seed index and seed phosphorus content. The inclusion of Azotobacter vinelandii significantly augmented various tested parameters, with the exception of seed yield, biological yield and potassium content, in comparison with Bradyrhizobium. Insignificant differences were found owing to the interaction between varieties, various levels of mineral fertilizers and types of biofertilizers with the exception of harvest index and seed phosphorus content.

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The Immuno-Electron Microscopic Localization of the Mo-Fe Protein Component of Nitrogenase in Cells of Azotobacter Vinelandii

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073313 ◽

1973 ◽

Vol 31 ◽

pp. 574-575

Author(s):

J. T. Stasny ◽

R. C. Burns ◽

R. W. F. Hardy

Keyword(s):

Cellular Localization ◽

Direct Evidence ◽

Azotobacter Vinelandii ◽

Intracellular Localization ◽

Protein Component ◽

Electron Microscopic ◽

Thin Sections ◽

Fe Protein ◽

Intracytoplasmic Membranes

Structure-functlon studies of biological N2-fixation have correlated the presence of the enzyme nitrogenase with increased numbers of intracytoplasmic membranes in Azotobacter. However no direct evidence has been provided for the internal cellular localization of any nitrogenase. Recent advances concerned with the crystallizatiorTand the electron microscopic characterization of the Mo-Fe protein component of Azotobacter nitrogenase, prompted the use of this purified protein to obtain antibodies (Ab) to be conjugated to electron dense markers for the intracellular localization of the protein by electron microscopy. The present study describes the use of ferritin conjugated to goat antitMo-Fe protein immunoglobulin (IgG) and the observations following its topical application to thin sections of N2-grown Azotobacter.

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Studies of Ge/Si(100) and Observation of Atomic Steps on Si(100) using Biassed Secondary Electron Imaging in a UHV STEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010018029x ◽

1990 ◽

Vol 48 (1) ◽

pp. 308-309

Author(s):

Mohan Krishnamurthy ◽

Jeff S. Drucker ◽

John A. Venablest

Keyword(s):

Secondary Electron ◽

Critical Thickness ◽

Surface Defects ◽

Film Growth ◽

Growth Parameters ◽

High Vacuum ◽

Ultra High Vacuum ◽

Surface Steps ◽

Epitaxial Crystal Growth ◽

Electron Imaging

Secondary Electron Imaging (SEI) has become a useful mode of studying surfaces in SEM[1] and STEM[2,3] instruments. Samples have been biassed (b-SEI) to provide increased sensitivity to topographic and thin film deposits in ultra high vacuum (UHV)-SEM[1,4]; but this has not generally been done in previous STEM studies. The recently developed UHV-STEM ( codenamed MIDAS) at ASU has efficient collection of secondary electrons using a 'parallelizer' and full sample preparation system[5]. Here we report in-situ deposition and annealing studies on the Ge/Si(100) epitaxial system, and the observation of surface steps on vicinal Si(100) using b-SEI under UHV conditions in MIDAS.Epitaxial crystal growth has previously been studied using SEM and SAM based experiments [4]. The influence of surface defects such as steps on epitaxial growth requires study with high spatial resolution, which we report for the Ge/Si(100) system. Ge grows on Si(100) in the Stranski-Krastonov growth mode wherein it forms pseudomorphic layers for the first 3-4 ML (critical thickness) and beyond which it clusters into islands[6]. In the present experiment, Ge was deposited onto clean Si(100) substrates misoriented 1° and 5° toward <110>. This was done using a mini MBE Knudsen cell at base pressure ~ 5×10-11 mbar and at typical rates of 0.1ML/min (1ML =0.14nm). Depositions just above the critical thickness were done for substrates kept at room temperature, 375°C and 525°C. The R T deposits were annealed at 375°C and 525°C for various times. Detailed studies were done of the initial stages of clustering into very fine (∼1nm) Ge islands and their subsequent coarsening and facetting with longer anneals. From the particle size distributions as a function of time and temperature, useful film growth parameters have been obtained. Fig. 1 shows a b-SE image of Ge island size distribution for a R T deposit and anneal at 525°C. Fig.2(a) shows the distribution for a deposition at 375°C and Fig.2(b) shows at a higher magnification a large facetted island of Ge. Fig.3 shows a distribution of very fine islands from a 525°C deposition. A strong contrast is obtained from these islands which are at most a few ML thick and mottled structure can be seen in the background between the islands, especially in Fig.2(a) and Fig.3.

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Cooptimization of growth parameters in glycerol mediated mixotrophic cultivation of microalgae in a bubble column photobioreactor

10.1021/scimeetings.0c03615 ◽

2020 ◽

Author(s):

Prof. Saikat Chakraborty ◽

Sreyashi Ghosh

Keyword(s):

Bubble Column ◽

Growth Parameters ◽

Mixotrophic Cultivation ◽

Bubble Column Photobioreactor

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Evaluation of Azadirachtin on Arthrospira plantensis Gomont growth parameters and antioxidant enzymes

Annales de Limnologie - International Journal of Limnology ◽

10.1051/limn/2020008 ◽

2020 ◽

Vol 56 ◽

pp. 8

Author(s):

Hatice Tunca ◽

Ali Doğru ◽

Feray Köçkar ◽

Burçin Önem ◽

Tuğba Ongun Sevindik

Keyword(s):

Enzyme Activity ◽

Growth Parameters ◽

Arthrospira Platensis ◽

Proline Content ◽

Enzyme Analysis ◽

Free Proline ◽

Sod Activity ◽

Pesticide Pollution ◽

Antioxidant Parameters ◽

Mda Content

Azadirachtin (Aza) used as insecticide due to inhibiting growth of insects and preventing them from feeding on plants. To understand the effects of contamination of this insecticide on phototrophs, and to determine the responses of these organisms against these insecticides are extremely important in understanding how the ecosystem is affected. In this study, chlorophyll-a amount, OD 560 and antioxidant parameters (total SOD, APX, GR, Proline, MDA and H2O2) were determined in order to understand the effect of Aza on Arthrospira platensis Gomont. Aza was applied between 0–20 μg mL−1 concentrations for 7 days in the study. Enzyme analysis was conducted at the end of the 7th day. There was a statistically significant decrease in the absorbance of OD560 and the chlorophyll-a content in A. platensis cultures exposed to the Aza (0–20 μg mL−1) during 7 days due to the increase in pesticide levels. SOD activity decreased at 8, 16 and 20 μg mL−1 concentrations; GR enzyme activity showed a significant decrease compared to the control at a concentration of 20 μg mL−1. APX activity did not change significantly compared to control. The MDA content increased significantly at 16 and 20 μg mL−1 concentrations. The H2O2 content significantly increased at 12, 16 and 20 μg mL−1 concentrations (p < 0.05) while the free proline content decreased at 4 μg mL−1 concentration (p < 0.05). As a result, regarding the Aza concentrations used in this study may be a step to prevent pesticide pollution in the environment.

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Ion Beam Sputter Deposition Of Ferroelectric Oxide Thin Films

MRS Proceedings ◽

10.1557/proc-223-273 ◽

1991 ◽

Vol 223 ◽

Cited By ~ 1

Author(s):

Thomas M. Graettinger ◽

O. Auciello ◽

M. S. Ameen ◽

H. N. Al-Shareef ◽

K. Gifford ◽

...

Keyword(s):

Thin Films ◽

Lead Zirconate Titanate ◽

Growth Parameters ◽

Ion Beam ◽

Lead Zirconate ◽

Electro Optic ◽

Integrated Optical ◽

Pzt Films ◽

Ion Beam Sputter Deposition ◽

Ferroelectric Oxide

ABSTRACTFerroelectric oxide films have been studied for their potential application as integrated optical materials and nonvolatile memories. Electro-optic properties of potassium niobate (KNbO3) thin films have been measured and the results correlated to the microstructures observed. The growth parameters necessary to obtain single phase perovskite lead zirconate titanate (PZT) thin films are discussed. Hysteresis and fatigue measurements of the PZT films were performed to determine their characteristics for potential memory devices.

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