This study aimed at cellulase production by Streptomyces drozdowiczii, a new cellulolytic species isolated in Brazil from forest soil, using agro-industrial by-products. Cellulase activity was partially characterized concerning the effect of pH and temperature on enzyme activity and stability. Its potential use in the textile and detergent industries was also assessed. The microorganism was cultivated at 30 degrees C using as main carbon sources, either carboxymethylcellulose (CMC), wheat bran (WB) or distillers dried grains (DDG), and as main nitrogen sources, yeast extract (YE) or corn steep liquor (CSL). Medium containing 0.3% (w/v) YE and 1% (w/v) CMC resulted on the highest CMCase level of 595 U/l. The supernatant, thus obtained, showed maximum CMCase activity at 50 degrees C and pH 5.0, conditions at which activity was stable up to I h. Concerning biotechnological applications the enzyme retained up to 87% of its initial activity upon incubation in the presence of commercials detergents for I h. In addition, the application of this enzyme on textile processing was evaluated through the loss of weight in cotton fabric, in comparison to the commercial enzyme IndiAge Super L. (c) 2005 Elsevier Inc. All rights reserved.