|1672-1||Production of cellulases by Streptomyces sp. grow on lignocellulosic wastes.|
|Autores:||Carolina C. Q. Brito-cunha (UFG - Universidade Federal de Goiás) ; Ivan T. N. Campos (UFG - Universidade Federal de Goiás) ; Fabrícia P. Faria (UFG - Universidade Federal de Goiás) ; Luiz Artur Mendes Bataus (UFG - Universidade Federal de Goiás) |
A strain of actinomycetes, isolated from sugar cane bagasse (SCB), identified as Streptomyces sp was selected for its ability to produce cellulase. The cellulase production was analyzed by submerged fermentation cultivation on minimal medium (MMi) containing cellulose-micro-crystalline (CMC), SCB or wheat bran (WB) as carbon source and yeast extract (YE) as source of nitrogen. The results showed that the wheat bran was the best inducer of the production of CMCase (2.0 U.mL-1). After determination of the culture medium allowing a higher production of CMCase, the production of cellulase was evaluated by measuring the activities of Avicelase, CMCase and FPase. The production of cellulolytic enzymes has been followed up for 12 days. The highest avicelase activity (5.646 Uml-1) was obtained in the eleventh, while CMCase (3.872 Uml-1) and FPase (0.0947 Uml-1) was obtained in the sixth day of cultivation. Cellulase activity was partially characterized concerning the effect of pH and temperature on enzyme activity. The thermostability and effects of different ions were also tested. The pH and temperature profile showed optimal activity at pH 7.0 at 35°C for Avicelase, pH 4.5 at 75°C for CMCase and pH 5 at 45°C for FPase. Zymogram analysis showed five bands with CMCase activity after electrophoresis and Congo red staining. The results showed the production of multiple cellulases, whose main characteristics are: act at elevated temperature (more than 80% of the activity at 50°C), effectiveness in a wide pH range (about 60% of activity over a wide pH range pH4,0 – pH9,0), thermostability (60% of activity after 2 hours at 60°C) and was not significantly inhibited by many metal ions. These features allow us to use these enzymes to develop new processes of biotechnological interest.
Palavras-chave: Avicelase, CMCase, Termoestabilidade