ABSTRACT
No presente trabalho, estudaram-se os efeitos de diversos parâmetros sobre a extração das proteínas caseína e albumina de soro bovino empregando micelas reversas de lecitina de soja. Independentemente da condição empregada, a extração da albumina apresentou baixo rendimento (variando de 0 por cento a 4 por cento, aproximadamente), resultado de um significativo efeito de exclusão por tamanho. Com relação à caseína, o rendimento da extração aumentou 23 vezes com o aumento do tempo de agitação, ou seja, com o maior tempo de contato entre a proteína e o sistema de micelas reversas. A adição de 1-hexanol ao sistema, usado como co-solvente, foi efetiva, aumentando a solubilização da caseína em 36 por cento, sendo os rendimentos da extração desta proteína muito influenciados pelo pH. Os valores máximos de eficiência obtidos foram de 20 por cento em pH 7,9, 80 por cento em pH 5,4 e 100 por cento em pH 5,0 (pH próximo ao pI da proteína).
In this work, the effect of different parameters for extraction of casein and bovine serum albumin (BSA) were studied. Such proteins were extracted by soybean lecithin reversed micelles. BSA extraction was not effective, independent of the extraction conditions employed. Owing to its molar mass, the effect of exclusion by size was clearly observed. The casein extraction yield increased about 23-fold as a function of agitation time. In other words, the increase occurred by using higher contact time between protein and reversed micelles. The use of hexanol as a co-solvent was effective, and increased casein extraction to 36 percent. The extraction values were strongly influenced by pH, and the high extraction yield was obtained under the following conditions: 20 percent at pH 7.9, 80 percent at pH 5.4 e 100 percent at pH 5.0 (close to casein isoelectrical point).
Subject(s)
Caseins , Micelles , Phosphatidylcholines , Glycine max , Albumins , Biotechnology/methodsABSTRACT
Glucose-6-phosphate dehydrogenase (G6PD) present in Saccahromyces cerevisiae is an enzyme of the pentose pathway. An effective enrichment of this intracellular enzyme can be achieved with the reversed micellar methodology. In this work, this methodology was employed with soybean lecithin, a biocompatible surfactant. A factorial design was used to evaluate the influence of pH (A) and extraction runs (B) on the G6PD purification factor. After statistical analysis and process optimization, a mathematical model representing G6PD enrichment was obtained: Y=4.89-0.83A+0.092B+0.27AB-1.37B2 with an enzyme purification factor of about 5.2.
