7-11: Production of cellulase and xylanase by thermophilic fingi under solid state and submerged fermentation by reutilization of the fermented substrate

The sugar cane bagasse is a residue produced in a large volume in the ethanol production process (280 kg by 1 ton of sugar cane) in Brazil. The high carbohydrate content of this residue became it an important substrate for fungi growth. The present work evaluated the use of mixture of sugar cane bagasse, corn straw and wheat bran as carbon source for cultivation of Humicola grisea 13.33, Chaetomium sp N13 e Thermomucor indicae-seudaticae N31 under solid state and submerged fermentations. The results showed that Chaetomium produced higher cellulase and xilanase activities in both fermentation systems, although in SSF the quantities of enzymes were significantly higher. The reutilization of fermented material, after enzyme extraction, as substrate for a new fermentation, revealed that the recalcitrance of lignocellulosic material increased after microbial the first growth with decreasing of fungal growth and enzyme production.

Key words: sugar cane bagasse, cellulase, xylanase