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Previous issue date: 2012-09-04 / Enzimas t?m sido largamente utilizadas em bioss?ntese para transforma??es
de compostos org?nicos em substitui??o aos m?todos sint?ticos cl?ssicos. Este
trabalho descreve a s?ntese enzim?tica de biossurfactantes a partir da Dglicose
com ?cido ricinol?ico empregando como biocatalisador a protease de
Bacillus subtillis alcalina. Com aux?lio do software MODDE 7.0, o planejamento
experimental utilizando um modelo fatorial 2 4-1 (planejamento reduzido de 2
n?veis e 4 vari?veis) foi realizado para verificar a influ?ncia das vari?veis
temperatura, tempo de rea??o, concentra??o de enzima e raz?o molar do
substrato/D-glicose sobre o rendimento da rea??o. An?lises de espectroscopia
na regi?o do infravermelho (FTIR) confirmaram a forma??o do produto atrav?s
de absor??es em 3400 cm-1, caracter?stica das hidroxilas presentes no anel do
a??car, e em 1739 cm-1, correspondente ? carbonila de ?ster. As an?lises de
CLAE (cromatografia l?quida de alta efici?ncia) mostraram as taxas de
convers?es alcan?adas pelo biocatalisador protease de Bacillus subtillis
alcalina. Medidas de tens?o superficial em diferentes condi??es, foram
realizadas com o produto de rea??o, onde observou-se redu??o da tens?o
superficial da ?gua de 72 mN/m para 33 mN/m. Foi poss?vel verificar tamb?m a
estabilidade quanto do produto frente as solu??es salinas (115 g/L), nas
solu??es tamp?o com pH extremos de 2 ? 12 e em solu??es aquosas
aquecidas no intervalo de 25 a 100 ?C. Visando aplica??o do produto em
t?cnicas Core-Flow (transporte de ?leo), an?lises de ?ngulo de contato pelo
m?todo da placa de Willemy foram realizadas, obtendo-se a redu??o do ?ngulo
de contato, do vidro com ?gua, de 40? para 0?. Nas an?lises como lubrificante e
redutor de filtrado em fluidos de perfura??o polim?ricos observou-se, nas v?rias
formula??es, que a mistura biodiesel/biossurfactante apresentou resultados
satisfat?rios reduzindo o CL (coeficiente de lubricidade) em 87% e o volume de
filtrado em 22%. Nos testes de forma??o e estabilidade de espuma,
caracter?stica que deve ser evitada por proporcionar leituras incorretas (peso espec?fico, reologia, volumetria, etc), nenhum dos biossurfactantes teve a??o
espumante caracterizando seu bom desempenho. / Enzymes 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.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/25056 |
| Date | 04 September 2012 |
| Creators | Medeiros, Suzan Ialy Gomes de |
| Contributors | 18822851404, Santos, Luciene da Silva, 27832155515, Souto, Carlos Roberto Oliveira, 28467809949, Medeiros, Ana Catarina da Rocha, 67215793400, Sant'ana, Hosiberto Batista de, 55184820434, Costa, Marta |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM QU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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