Costa, MartaMedeiros, Suzan Ialy Gomes de2018-04-132018-04-132012-09-04MEDEIROS, Suzan Ialy Gomes de. Obtenção do Ricinoleato de D-glicose e sua aplicação em fluidos de perfuração. 2012. 109f. Tese (Doutorado em Química) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2012.https://repositorio.ufrn.br/jspui/handle/123456789/25056Enzymes have been widely used for organic compounds biosynthesis, attracting a great deal of attention in recent years, due to its several advantages over the chemical method. This work describes the enzymatic synthesis of biosurfactants from d-glucose with ricinoleic acid using proteases Bacillus subtillis alcalina as biocatalysts. Aiming to reach high conversions from substrates to products for a possible future large scale industrial production, a serie of variables was optimized, through MODDE 7.0, using the factorial model design 24-1. The investigated variables were: temperature, reaction time, enzyme concentration and substrate/D-glicose rate. Qualitative analysis by infrared spectroscopy (FTIR) confirmed the product formation through characteristic peaks due to hydroxyl group absorption on the sugar ring at 3400 cm-1 and the carbonyl group at 1739 cm-1, which refers to ester carbonyl. HPLC analysis (High Performance Liquid Chromatography) showed higher conversions using of alkaline protease of Bacillus subtillis. Besides, it was observed that all the biosurfactants reduced the surface tension of water from 72 to 33 mN/m (by interpolate of the plate method). According to surface tension results, it was possible to evaluate the stability of each product about saline (maximum 115g/L) and buffer solutions (pH 2 – 12), from a temperature range from 25 to 100°C). Aiming its application to core-flow technique, contact angle measurements presented reduction of 40° to 0° in presence of d-glucose ricinoleate, when compared to distillated water. Different applications of this product were investigated, such as: lubricant and filter loss control for polymeric drilling fluids of petroleum wells. It was observed the reduction of lubricity coefficient and filtrate loss control in 87 and 22 %, respectively.Acesso AbertoRicinoleato de d-glicoseÁcido ricinoléicoGlicoseProteaseTensão superficialMolhabilidadeEspumanteLubrificanteRedutor de filtradoFluido de perfuraçãodoctoralThesisCNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA