54 research outputs found

    Application of botryosphaeran as a carbon black adherent on a glassy carbon electrode for the electrochemical determination of cyclobenzaprine

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    The present work describes the performance of a new voltammetric sensor based on the modification of glassy carbon electrodes (GCE) with carbon black (CB) and botryosphaeran (BOT) (CB-BOT/GCE) for the electroanalytical determination of cyclobenzaprine. BOT is a fungal exocellular (1→3)(1→6)-β-ᴅ-glucan, which was used to improve the adherence of CB onto the surface of GCE. The electrochemical characterisation was performed by electrochemical impedance spectroscopy which showed an improvement in the transfer of electrons on the surface of the sensor developed in relation to the unmodified (bare) GCE. The voltammetric behaviour of cyclobenzaprine was studied using bare GCE, BOT/GCE, CB/GCE, and CB-BOT/GCE. All electrodes presented an oxidation peak (+ 1.0 V) for cyclobenzaprine, while the cyclobenzaprine peak intensity on CB-BOT/GCE was found to be 480% higher than the bare GCE. Through employing square-wave voltammetry, the analytical curve was found to be linear over the concentration range of 2.0 to 20.6 μmol L−1 (in 0.1 mol L−1 NaCl solution) with a detection limit (based on 3-sigma) of 0.63 μmol L−1. The developed electrochemical sensor exhibited excellent sensitivity and selectivity and was successfully applied for the voltammetric determination of cyclobenzaprine in pharmaceutical, biological, and environmental samples for the first time using the CB-BOT/GCE electrochemical sensing platform

    Comparison of lipase production on crambe oil and meal by Fusarium sp (Gibberella fujikuroi complex)

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)This study provides a comparison of fermentation conditions for the production lipases by Fusarium sp. (Gibberella fujikuroi complex) isolate FCLA-MA-41 in submerged (SmF) and solid-state fermentation (SSF) using agro-industrial residues. To assess SmF, a univariate study of seven carbon sources (crambe, corn, linseed, olive, palm (dende), soybean oils and chicken fat) and four nitrogen sources (ammonium sulfate, sodium nitrate, urea, yeast extract) was performed. The relationship among the concentrations of carbon and nitrogen sources, Triton X-100 and yeast extract was studied using a Central Composite Design (CCD). To assess SSF, different residues (sugarcane bagasse) and oil-seed meals (castorbean, corn, crambe, soybean) with additional supplements added (minimum salts, seed oils) were examined. Based on the CCD matrix, a medium containing crambe oil (17.5mL/L), Triton X-100 (5g/L), ammonium sulfate (5g/L) and yeast extract (1g/L) was proposed, resulting in a lipase titer of 3.0 +/- 0.25U/mL. The cost/production relationship was 7.73% less expensive than SmF with corn oil. SSF produced a maximum lipase titer of 5.0 +/- 0.25U/gds on crambe meal moistened with phosphate buffer. The best cost/enzyme activity estimate was for SSF with crambe meal as substrate in only distilled water (87.27% less expensive than SmF).11512SI14131425Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)FAPESP [2010/07998-9

    Botryosphaeran, a new substrate for the production of beta-1,3-glucanases by Botryosphaeria rhodina and Trichoderma harzianum Rifai

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    Botryosphaeria rhodina and Trichoderma harzianum Rifai were grown on botryosphaeran (an exopolysaccharide (EPS) of the beta-1,3; 1,6-D-Glucan type produced by B. rhodina) as sole carbon source with the objective of producing beta-glucanases of the beta-type. Conditions for beta-1,3-glucanase production by T harzianum were examined by a statistical response surface method, and showed maximal enzyme production at 5 days growth in media containing 1.5 g/1 of EPS. Good agreement was obtained between the experimental values of beta-1, 3-glucanase activity and the corresponding values predicted by the mathernatical model. The crude beta-1,3-glucanase preparations were active towards a number of different beta-1,3-glucans and beta-glucosides. The mycelium of B. rhodina also proved to be a good substrate for beta-1,3-glucanase production by both fungal species. (c) 2005 Published by Elsevier Ltd

    Enzymatic hydrolysis of botryosphaeran and laminarin by beta-1,3-glucanases produced by Botryosphaeria rhodina and Trichoderma harzianum Rifai

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    Botryosphaeran, a (1 -> 3; 1 -> 6)-beta-D-glucan produced by Botryosphaeria rhodina, and laminarin were hydrolysed by two fungal beta-glucanases predominantly of the 1,3-type produced by B. rhodina and Trichoderma harzianum Rifai grown on botryosphaeran as sole carbon source. Both beta-glucanase preparations presented different modes of attack on botryosphaeran and laminarin. Laminarin was hydrolysed to the extent of similar to 50% in 1 hand 100% within 24 h, and its hydrolysis products were mainly glucose and gentiobiose, and lesser amounts of laminaribiose and oligosaccharides of DP 3-4 during the early stages of hydrolysis, while botryosphaeran 'yielded mainly glucose and gentiobiose with some trisaccharide, but no laminaribiose or tetrasaccharide when hydrolysed by the T. harzianum enzyme. By contrast, B. rhodina beta-1,3-glucanases produced predominantly glucose during all stages of botryosphaeran hydrolysis. Some physicochemical properties of the 1,3- and 1,6-beta-glucanases, and beta-glucosidases contained in the two fungal P-glucanase preparations are also described for the first time. (c) 2006 Elsevier Ltd. All rights reserved

    Purification and structural characterisation of (1 -> 3 ; 1 -> 6)-beta-D-glucans (botryosphaerans) from Botryosphaeria rhodina grown on sucrose and fructose as carbon sources: a comparative study

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    Two botryosphaerans, exopolysaccharides (EPS) secreted by the ascomyceteous fungus Botryosphaeria rhodina, when grown on sucrose and fructose as sole carbon sources, were structurally compared after their isolation from the culture medium. Both EPS were submitted to trypsin digestion, and eluted as a single peak on gel filtration. Total acid hydrolysis yielded only glucose, and data from methylation analysis and Smith degradation indicated that both EPS constituted a main chain of glucopyranosyl beta(1 -> 3) linkages substituted at O-6. The products obtained after partial acid hydrolysis demonstrated side chains consisting of glucosyl- and gentiobiosyl- linked beta(1 -> 6) residues. C-13-NMR spectroscopy studies showed that all glucosidic linkages were of the beta-configuration. The carbon source affected the side chain structures of botryosphaeran but not the main chain makeup. Sucrose produced less branching (21%) than fructose (31%). (c) 2005 Published by Elsevier Ltd
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