Abstract

Holocellulolytic accessory enzymes are very important in assisting hydrolysis of biomass. The use of these enzymes in the enzymatic hydrolysis of plant biomass is very important for obtaining building blocks in the concept of biorefinery. In previous studies, the mutant strain Trichoderma atroviride 102C1 was tested for production of endoglucanases, FPases and endoxylanases. This study aimed at evaluating the efficiency in holocellulolytic accessories enzymes production (b-glucosidase, b-xylosidase and a-L-arabinofuranosidase) by Trichoderma atroviride 102C1 using different lignocelluloses biomass as substrates. Accessory enzymes production was carried out in Erlenmeyer flasks containing Mandels salt medium, supplemented with different concentrations of sugarcane bagasse (SCB) and corn steep liquor (CSL), according to a Central Composite Rotational Design (CCRD). The fermentation system was incubated under agitation for 2 days / 28°C. For pH and temperature profile studies, a new CCRD was carried out. The best condition common to all enzymes, 55.4 U.mL^-1 (β-glucosidase), 10.8 U.mL^-1 (β-xylosidase) and 143.23 U.mL^-1 (α-L-arabinofuranosidase), was observed when 2.5% (w/v) sugarcane bagasse (SCB) and 1.26% (w/v) of corn steep liquor (CSL) were used. All enzymes presented acidophilic characteristic in two different temperatures (44 and 55°C). The optimal profile characteristic for β-glucosidase and β-xylosidase activities were pH 5.0 and 3.0, respectively, both at 55°C, while for α-L-arabinofuranosidase it was pH 3.6 at 44°C. This study demonstrated the potential of T. atroviride 102C1 to produce three important holocellulolytic accessory enzymes in the presence of SCB and CSL, suggesting its use for enzymatic hydrolysis of lignocellulosic biomass.

Key words: Trichoderma atroviride 102C1, holocellulolytic enzymes, sugarcane bagasse, corn steep liquor.