Produção de biossurfactantes por Bacillus subtilis LAMI005 utilizando suco de caju clarificado

• Ano de defesa: 2010
• Autor(a) principal: Oliveira, Darlane Wellen Freitas de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Engenharia química; Bacillus subtilis; Suco de caju
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/15753

The purpose of this study was evaluate the biosurfactants potential production of the microorganism Bacillus subtilis LAMI005 using clarified cashew apple juice as carbon source. The microorganism production capacity was evaluated with preliminary test using mineral medium as inoculum and cultivation, and glucose and fructose standard analytical as carbon source. Subsequently, the influence of carbon source variation was evaluated keeping the supplementation of nitrogen source constant at 1.0 g.L-1 (NH4)2SO4. Kinetic study was conducted to assess the feasibility of substrate bioconversion used in a value-added product, surfactin, and the type of formed metabolite. The test with mineral medium with initial concentrations of 40.87 g.L-1 TRS were obtained the higher biomass concentration and surfactin of 2.5 g.L-1 and 137 mg.L-1 respectively in 72 hours of testing. The lower surface tension reduction of the medium rich in surfactin was around 27.0 dyne.cm-1, representing 55% reduction. The pH remained in a range from 6.0 to 7.0. By varying the carbon source and initial concentrations of TRS 12.71 g.L-1, 22.92 g.L-1, 48.96 g.L-1, 65.04 g.L-1, 96.10 g.L-1 and 40.65 g.L-1 + 0.1% solution of micronutrients, the highest yield was obtained in surfatin test concentration of TRS of 22.92 g.L-1 reaching a value of 372.56 g.L-1 in 48 hours. The highest concentration of biomass obtained for assays with variation in initial concentrations of TRS were 2.05 g.L-1, 5.3 g.L-1, 7.49 g.L-1, 8.6 g.L-1, 8.4 g.L-1 and 7.14 g.L-1 respectively, for concentrations above TRS. All tests showed residual carbon at the end of the process, reaching pH values much acid to 4.0, being stable in the range between 6.0 and 7.0 only at test concentrations of 96.10 g.L-1 TRS. Surfactant produced showed good emulsifying capacity, around 50% in hydrocarbons such as kerosene and soybean oil and formed stable emulsions, reaching values around 2.0 U. Fermentations varying the concentration of carbon source showed maximum specific growth (μxmáx) similar. The specific growth rates (μx), substrate consumption (μs) and biosurfactant production (μp) fitted quite well, we conclude that the product formation is a primary metabolite and is associated with growth. The mathematical model used for testing fermentative fitted well to the experimental data, proving the feasibility of bioconversion of the substrate in surfactin.