Production and characterization of endoglucanase secreted by Streptomyces capoamus isolated from Caatinga
Cellulases are hydrolases of great importance to industries, especially due to their ability to produce ethanol via hydrolysis of cellulolytic materials. Actinomycetes are the producers of these enzymes, particularly the genus Streptomyces sp. The present study is the first report on the production and characterization of cellulolytic complex secreted by Streptomyces capoamus, isolated from the rhizosphere soil of Caatinga. In selecting the microbial producers of cellulolytic complex in qualitative tests, 171x microorganism showed the most expressive enzymatic index. Regarding the production time of the complex, fermentation was done for 7 days, with aliquots being taken every 24 h. Peak production was obtained during 48 h fermentation. It was done at 37ºC and under an agitation of 180 rpm. It was noted also that the 171x micro-organism produced the enzyme in greater quantity. The experiment was done with the most significant actinomycetes (171x), optimal substrate concentration (carboximeticellulose), cultivation temperature and pH of initial output. The results showed that a higher cellulolytic complex was obtained with 2% substrate, 45°C temperature and initial pH 4.0. The microorganism was identified at genus level by microculture method; and with molecular identification method, it was identified as S. capoamus UFPEDA-3410. In optimal culture conditions, this strain produced 0.309 U/mL cellulose, a good production for a thermostable endoglucanase stable in a broad range of pH and stable temperature. It has potential applications in a wide range of industries. Industrial processes are generally carried out at elevated temperatures. Therefore enzymes with a high optima temperature and stability are desired for such applications.
Key words: Cellulase activity, actinomycetes, fermentation, carboxymethyl cellulose.