Monday, April 30, 2007

Cellulase production by Streptomyces malaysiensis AMT-3 using agro-industrial by-products in biorreactor

Rodrigo P. Nascimento1, Nei Pereira Jr2, Elba Bon3, Rosalie R. R. Coelho4, F.M. Gírio5, and Alberto D. Reis5. (1) Centro de Ciências Agrárias, Ambientais e Biológicas, Universidade Federal do Recôncavo da Bahia, Cruz das Almas, Brazil, (2) Escola de Química, Federal University of Rio de Janeiro, Centro de Tecnologia, Rio de Janeiro, Brazil, (3) Biochemistry - Chemistry Institute, Federal University of Rio de Janeiro, Instituto de Quimica, sala 539 - Cidade Universitaria, Ilha do Fundao, Rio de Janeiro, Brazil, (4) Microbiology Institute, General Microbiology Department, Federal University of Rio de Janeiro, CCS, bloco I, Ilha do Fundão, UFRJ, Rio de Janeiro, Brazil, (5) Biotechnology Department, INETI, Estrada do Paço do Lumiar, 22, Lisboa, 1649-038, Portugal

The streptomycetes are filamentous bacteria with great potential for enzyme production, as cellulases, important for detergents, textile and food industries, and also for agro-industry residue treatment and poultry ration production. Cheaper cellulosic substrates like agro-industrial by-products could be used for the production of cellulases. In this work, a 22 factorial design was performed to optimize the culture conditions for cellulase production by Streptomyces malaysiensis AMT-3. The independent response used were agitation speed (300 – 600 rpm) and aeration rate (0.5 – 1.5 vvm). The fermentation systems were carried out at 30ºC for 6 days. The highest enzyme activity (710 U.L-1) was obtained after 4 days–fermentation at 30°C in mineral medium containing 2.5% (w/v) wheat bran and 1.2% (w/v) corn steep liquor. Best enzyme activity was observed at 50oC and pH 5.0. The enzyme retained 50% of its activity after 2 hours at 50°C. The results suggest that the cellulases production could be carried out using agro-industrial by-products, minimizing the impact of the production, and consequently contributing for the use of cleaner technologies.

 Financial Support: CNPq (201080/2004-4), FAPERJ, FINEP, FAPESB