oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Phosphorus Degradation Capability of Aspergillus terreus on Nigeria’s Agbaja Iron Ore  [PDF]
C.N. Anyakwo, O.W. Obot
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2011, DOI: 10.4236/jmmce.2011.1012091
Abstract: A microbial fungus - Aspergillus terreus was used to degrade phosphorus in Nigeria’s Agbaja iron ore in the laboratory. The ore was first crushed to very tiny particles, screened using Shital test kits and 1.00/0.50mm, 0.50/0.25mm and 0.25/0.125mm particle size fractions were selected for the experiment. The microbes, obtained from the nascent remains on the ore environment, were cultured, used to inoculate 1g of sterile ore samples in 250ml conical flasks containing 100ml of equally sterile malt extract broth media and left to stand. At weekly interval, the samples were removed, treated through series of chemical reactions and ammonium phospho-molybdate precipitate was obtained. This was back-titrated with 0.1 NHCl to determine the amount of phosphorus left in samples and consequently, the amount removed. Findings reveal that A. terreus is capable of degrading the ore samples. pH monitoring reveals that the P degradation process proceeded in a culture media of increasing acidity. It is recommended to further study the chemistry of the mixture of culture media, ore samples and microbes to find parameters that favour the degradation process. Key words: Ore, microbes, screening, broth, degradation, accumulation, inoculati
Laboratory Studies on Phosphorus Removal from Nigeria’s Agbaja Iron Ore by Bacillus Subtilis  [PDF]
C. N. Anyakwo, O.W. Obot
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2011, DOI: 10.4236/jmmce.2011.109063
Abstract: The investigation into whether or not Bacillus subtilis can remove phosphorus from the Nigerian Agbaja iron ore was carried out with careful monitoring of the population of the removing agent as well as pH of the system. 1.00mm/0.50mm, 0.50mm/0.25mm, and 0.25mm/0.125mm ore fractions obtained from sieving of the crushed iron ore in Shital Test kits, were used in sub-merged culture of nutrient broth (NB) medium for 10 weeks. B. subtilis which was part of the rich microflora found on the ore surface was cultivated in nutrient-rich media and later inoculated in sterilized 100ml of NB in 250ml conical flask and 1g of each of the equally sterilized ore fractions was added. At weekly intervals, a set of samples was removed, treated through series of chemical reactions to obtain ammonium phosphomolybdate precipitate which was back-titrated with 0.1 N-HCl to determine the amount of phosphorus left in samples and consequently, the amount removed. The laboratory investigations found out that B. subtilis has the capability to remove phosphorus from the Nigerian Agbaja iron ore, recording an impressive average of 65.73% P. Also found out was the systematic reduction in bacterial cells count in colony forming unit per mililitre, the initial load 3.4x105 cfu/ml increased to 4.8x107 cfu/ml from where it declined to 1.3x106 cfu/ml, which justified the pH trend observed during the process of cumulative phosphorus removal. The reduction in microbial activity may be attributed to antimicrobial components of the ore, pyrite, and other heavy metals which may have affected the phosphorus uptake from ore.
Hydrometallurgical Process of Dephosphorization of Agbaja Iron Ore  [cached]
T.O. Chime,O.D. Onukwuli,A.J. Ujam
Journal of Asian Scientific Research , 2012,
Abstract: A study on the dephosphorization of Agbaja Iron Ore using hydrometallurgical process has been carried out. The central composite design of 23 response was formulated and used to develop a model equation. The optimized result of the equation using Matlab shows that 97.97% degree of dephosphorization was obtained at 117 minutes leaching time, 0.2M leachant concentration and particle size of 30 microns. Iron loss during the hydrometallurgical leaching was less than 5%. It can be inferred that chemical leaching using HCl is attainable under the prevailing conditions of the experiment.
Comparative Phosphorus Removal Capabilities of Eurotium Herbarorium and Clostridium Species on Nigeria’S Agbaja Iron Ore  [PDF]
O. W. Obot, C. N. Anyakwo
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2012, DOI: 10.4236/jmmce.2012.118077
Abstract: A study of phosphorus removal capabilities of Eurotium herbaroriumand Clostridium species from Nigeria’s Agbaja iron ore was carried out. Iron ore sample was crushed, sievedto obtain0.50 mm/0.25 mmparticle size distribution and cultured with mineral oil medium to facilitate microbial growth. Fungi and bacteria that concurrently grew weresubcultured in Sabouard dextrose agar and nutrient agar solutions that support fungal and bacterial growth, respectively,andcharacterized using standard procedures.Ore was exposed to these microbes to effect phosphorus removal in standard media and later analyzed at weekly interval using the standard volumetric ammonium phosphomolybdate method. The fermentation broth media were analyzed for iron, copper, cadmium, zinc, nickel, manganese and lead using the atomic absorption spectrophotometer. The microorganisms markedly removed phosphorus from the ore with 61.48% and 69.20%, respectively. For the funguspH remained in the acidic region and basic for the bacterium. Trace elements analyses of the initial and final orecontaining media recorded marked reduction in the concentration of these elements. A plausible explanation that is supported by literature is that the microorganisms accumulated them. This probably accounts for the drastic decrease in fungal biomass and bacterial density with the concomitant decrease in phosphorus removal observed towards the end.
Antagonism of Aspergillus terreus to Sclerotinia sclerotiorum
Melo, Itamar S.;Faull, Jane L.;Nascimento, Rosely S.;
Brazilian Journal of Microbiology , 2006, DOI: 10.1590/S1517-83822006000400002
Abstract: an aspergillus terreus strain showed in vitro antagonistic activity against the plant pathogen sclerotinia sclerotiorum (lib.) de bary. the interaction between a. terreus and sclerotia revealed that the mycoparasite sporulated abundantly on the sclerotial surface. cell breakdown due to host cell wall disruption was observed in inner rind cells, by a scanning electron microscopy.
Genetic variability of Aspergillus terreus from dried grapes  [PDF]
Banu Narasimhan, Madhivathani Asokan
Advances in Bioscience and Biotechnology (ABB) , 2010, DOI: 10.4236/abb.2010.14046
Abstract: RAPD was used to examine the genetic variability among five isolates of Aspergillus terreus spp.. Two random primers were selected for the RAPD assay PG01–5’ CAGGTGTTGC 3’ and PG02–5’ CTGGACAGAC 3’ (Progen Technologies). The characterization of Aspergillus terreus species have been mostly applied on the basis of morphology, phenotype and physiology. DNA Polymorphisms are based on differences in DNA sequences and have advantages over protein polymorphisms. But morphological characterization besides molecular tools will remain a basic and powerful key in the identification of Aspergillus terreus species. The objective of the present study was to isolate the fungal contaminants from dried grapes and compare the genomic profile of the Aspergillus terreus speices isolated from the dried grapes, through RAPD analysis. In the present study with primer PG 01 four different discriminations was there among the A. terreus isolates. There was a homology of genotype between the isolates 1 & 3. And with primer PG 02 four different discriminations were there and there was a homology between 1 & 3. The predominant type was type I in primer I & II. The other isolates belonged to 2, 3 and 4. No similarity was detected for isolates 3, 4 and 5 indicating great genomic diversity of A. terreus.
Strain improvement of Aspergillus terreus for increased lovastatin production  [PDF]
N. Jaivel,,P. Marimuthu
International Journal of Engineering Science and Technology , 2010,
Abstract: Strain improvement of Aspergillus terreus was carried out by physical and chemical mutagenesis for increased lovastatin production. The spore survival of Aspergillus terreus strain JPM3 after different periods of exposure to UV light and Ethyl Methane Sulphonate was assessed. Four mutant clones were obtained by the mutagenesis programme. In which two mutants were derived by UV irradiation and another two mutants derived by EMS treatment. The yield of lovastatin varied from mutant to mutant and the mutant strain JPM3-UV1 produced the maximum lovastatin yield (1553.02 mg l-1) followed by strain JPM3-EMS2 (948.5 mg l-1).
Modification of c and n sources for enhanced production of cyclosporin 'a' by Aspergillus Terreus
Tanseer, Sundas;Anjum, Tehmina;
Brazilian Journal of Microbiology , 2011, DOI: 10.1590/S1517-83822011000400019
Abstract: most of the studies regarding cyclosporin 'a' production through fungi concentrate around tolypocladium inflatum. this is mainly due to lower reported production of this drug in other fungi. the present study was therefore conducted to explore indigenous isolates of aspergillus terreus for synthesis of this drug and defining a production medium for obtaining high yield of cyclosporin 'a'. for this purpose carbon and nitrogen sources were optimized for the selected best strain of a. terreus. overall results depicted that the best cyclosporin 'a' yield from selected aspergillus terreus (fcbp58) could be obtained by using production medium containing glucose 10% as carbon source and peptone 0.5% as nitrogen source. this modification in production medium enhanced drug synthesis by selected fungi significantly. the production capabilities when compared with biomass of fungi there was found no relationship between the two confirming that the medium modification increased overall drug synthesis powers of the fungi.
EVALUATION OF STRUCTURAL AND BIOCHEMICAL ALTERATIONS IN ASPERGILLUS TERREUS BY THE ACTION OF ANTIFUNGAL ANTIBIOTIC COMPOUND FROM STREPTOMYCES SP. JF714876  [PDF]
Babanagare Shankaravva S.,Vidyasagar G.M.
International Research Journal of Pharmacy , 2011,
Abstract: Antifungal compound obtained by Streptomyces sp. JF714876 was examined for its effect on morphological and biochemical alteration in Aspergillus terreus. Microscopic observation revealed swelling of hyphae with deformation and distortion in mycelial structure in presence of moderate concentration of antifungal compound. At high concentration, the compound exhibited fungicidal action. Antifungal treated Aspergillus terreus showed changes in its biochemical content such as, protein, carbohydrates, peroxidase, catalase and amylase as compared to untreated.
PhoR/PhoP two component regulatory system affects biocontrol capability of Bacillus subtilis NCD-2
Guo, Qinggang;Li, Shezeng;Lu, Xiuyun;Li, Baoqing;Ma, Ping;
Genetics and Molecular Biology , 2010, DOI: 10.1590/S1415-47572010005000032
Abstract: the bacillus subtilis strain ncd-2 is an important biocontrol agent against cotton verticillium wilt and cotton sore shin in the field, which are caused by verticillium dahliae kleb and rhizoctonia solani kuhn, respectively. a mutant of strain ncd-2, designated m216, with decreased antagonism to v. dahliae and r. solani, was selected by mini-tn10 mutagenesis and in vitro virulence screening. the inserted gene in the mutant was cloned and identified as the phor gene, which encodes a sensor kinase in the phop/phor two-component system. compared to the wild-type strain, the apase activities of the mutant was decreased significantly when cultured in low phosphate medium, but no obvious difference was observed when cultured in high phosphate medium. the mutant also grew more slowly on organic phosphate agar and lost its phosphatidylcholine-solubilizing ability. the suppression of cotton seedling damping-off in vivo and colonization of the rhizosphere of cotton also decreased in the mutant strain when compared with the wild type strain. all of these characteristics could be partially restored by complementation of the phor gene in the m216 mutant.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.