%0 Journal Article
%T Cellulase and Xylanase Production by Penicillium echinulatum in Submerged Media Containing Cellulose Amended with Sorbitol
%A Carla Eliana Todero Ritter
%A Marli Camassola
%A Denise Zampieri
%A Mauricio Moura Silveira
%A Aldo Jos¨¦ Pinheiro Dillon
%J Enzyme Research
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/240219
%X The present work investigated the use of sorbitol as a soluble carbon source, in association with cellulose, to produce cellulases and xylanases in submerged cultures of Penicillium echinulatum 9A02S1. Because cellulose is an insoluble carbon source, in cellulase production, there are some problems with rheology and oxygen transfer. The submerged fermentations containing media composed of 0, 0.25, 0.5, 0.75, and 1% (w/v) sorbitol and cellulose that were added at different times during the cultivation; 0.2% (w/v) soy bran; 0.1% (w/v) wheat bran; and a solution of salts. The highest filter paper activity (FPA) ( £¿IU¡¤mL£¿1) was obtained on the seventh day in the medium containing 0.5% (w/v) sorbitol and 0.5% (w/v) cellulose added 24 h after the start of cultivation. However, the CMCases showed an activity peak on the sixth day ( £¿IU¡¤mL£¿1) in the medium containing 0.75% (w/v) sorbitol and 0.75% (w/v) cellulose added after 12 h of cultivation. The xylanases showed the highest activity in the medium with 0.75% (w/v) sorbitol and 0.25% (w/v) cellulose added 36 h after the start of cultivation. This strategy enables the reduction of the cellulose concentration, which in high concentrations can cause rheological and oxygen transfer problems. 1. Introduction Lignocellulosic biomass has been projected to be one of the main resources for economically attractive bioethanol production, and enzymatic hydrolysis is the most potent alternative process for the saccharification of its polymers. Cellulase is an enzyme complex capable of hydrolyzing cellulose into glucose molecules [1], and xylanases degrade xylan, the main carbohydrate present in some hemicelluloses, into xylose [2]. Although cellulases and xylanases have several industrial uses, the greatest potential use of these enzymes is in the enzymatic hydrolysis of lignocellulosic materials to produce second-generation ethanol [3]. The cellulase complex has three major hydrolases: the endo- -1,4-glucanases (EG I, EG II, EG III, EG IV, and EG V; EC 3.2.1.4), which hydrolyze the glucosidic bonds randomly in cellulose fiber; the exo- -1,4-glucanases or cellobiohydrolases (CBH I and CBH II; EC 3.2.1.91), which act on the reducing and nonreducing ends of polymers, releasing cellobiose; and the -1,4-glucosidases (BG I and BG II; EC 3.2.1.21), which hydrolyze oligosaccharides and cellobiose into glucose [4]. The xylanolytic complex capable of hydrolyzing xylan is usually composed of several enzymes, such as -1,4-endoxylanase, -xylosidase, -L-arabinofuranosidase, -glucuronidase, acetyl xylan esterase, and the phenolic,
%U http://www.hindawi.com/journals/er/2013/240219/