Purificação parcial e caracterização de uma celulase produzida por Streptomyces sp. S5 e sua aplicação em panificação
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2020-03-30
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Universidade Federal de Goiás
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Cellulases are an enzymatic complex made up of endoglucanases, exoglucanases and β-glycosidases, and have several biotechnological applications. Some filamentous bacteria like Streptomyces sp are used in enzymatic degradation processes, and have potential to produce enzymes of biotechnological interest. The search for cellulases with more suitable properties for industrial application has increased in recent year. In the bakery industy, these enzymes act on the dough, changing physical-chemical and sensory characteristics. Thus, improving the final quality of the product and increasing the useful life. Given the above, the present study aims to characterize and purify cellulase enzyme produced during the growth of Streptomyces sp. S5, using the submerged fermentation technique. Also evaluate its application in the production of refined and whole breads. So, microorganism was grown in Pridham medium for 6 days at 36º C, the crude extract was obtained and its cellulolytic activity was determined by tge CMCase activity. The partially purified extract was obtained by Ultrafiltration (Ultracel 10 kDa) and gel filtration chromatography (Sephacryl S-100). The enzyme was characterized by effect of pH, temperature and metal ions on its activity, and thermal stability. The enzyme of the partially purified extract was applied in the formulation of refined and whole wheat bread, in concentrations of 2.5, 5.0, 7,5. And 15 U/100 g of flour. The influence on the specific volume, texture and color of the final product was evaluated. As a result, the partially purified extract showed an enzyme with a molecular mass of 32 kDa, with activity for CMCase in a determined by zymogran. It showed an optimum activity at pH 5.5, and na optimum temperature at 55ºC. Thermostability with maintenance of more than 60% of activity at 50ºC in up one hour. Above 60% of activity at 60ºC, except in the fifith hour. More than 100% activity in the first hour at 70ºC, keeping above 80% between 2 and 4 hours of incubation. The enzymatic activity was inhibited by the presence of CaCl2, HgCl2, MgCl2 e NaCl, KCl and FeSO4. The characterization of the breads shows an increase in specific volume, and a decrease in hardness in the presence of cellulase enzyme in all concentrations. There were changes in luminosity, indicating a increase in Maillard reactions, and a decrease in color intensity. Thus, it is concluded that the cultivation of Streptomyces sp. S5 using the submerged fermentation technique is effective in the production of cellulase enzyme. The properties of the cellulase enzyme obtained in this study makes it useful in application in biotechmological processes such as bread production, providing improvements in the physical and sensory qualities of the product.
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RIBEIRO, Bruna Fernandes. Purificação parcial e caracterização de uma celulase produzida por Streptomyces sp. S5 e sua aplicação em panificação. 2020. 71 f. Dissertação (Mestrado em Ciência e Tecnologia de Alimentos) - Universidade Federal de Goiás, Goiânia, 2020.