17 research outputs found

    Temperature effect on dextransucrase production by Leuconostoc mesenteroides FT 045 B isolated from Alcohol and Sugar Mill Plant

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    Temperature (23 to 31 degrees C) and sucrose concentration ( 3 and 4%) effects on dextransucrase production by Leuconostoc mesenteroides NRRL B 512 ( F) and Leuconostoc mesenteroides FT 045 B were studied. The conditions in all fermentations were: total reaction volume 2 L, 132 rev. min-1, 0.5 vvm and pH 6.0. The optimum temperature for enzyme yield for strain NRRL B 512 ( F) was 23 degrees C, where at 8-h fermentation was possible to achieve 49.3 DSU/mL. When FT 045 B strain was utilized, 3.2 DSU/mL was obtained at temperature 23 to 25 degrees C

    Effect of C/N Ratio and Physicochemical Conditions on the production of Rhamnolipids by Pseudomonas Aeruginosa LBI

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    Waste utilization for biosurfactant production is an important approach contributing to the reduction of waste treatment costs, while increasing the economic value of residues and reducing biosurfactant production costs: In an attempt to optimize rhamnolipid production by Pseudomonas aeruginosa LBI, the effects of the oil refinery waste as carbon source, C/N ratio, agitation speed, aeration rate, pH control and fed-batch culture conditions on the production of this biosurfactant were assessed in a bioreactor. Maximum production (16.9 g L(-1)) was attained at a C/N ratio of 23; agitation at 800 rpm and aeration at 2.0 vvm. The rhamnolipid solution (0.1%, w/v) exhibited surface and interface tensions of 25 mN/m and 0.63 mN/m respectively. The critical micelle concentration (CMC) was 73.9 mg L(-1). The optimal parameters used in this study promoted the formation of a useful biosurfactant with potential for many industrial applications.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP
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