Cellulose biosaccharification by Irpex lacteus wood decay fungus

Abstract

Enzymatic hydrolysis is an environmentally friendly technology to produce sugars from pretreated biomass. Here, we show that the new Il-11 Irpex lacteus strain can synthesize cellulases in a high quantity. The peptone and filter paper contained in the medium significantly enhanced activity of endo-1,4-β-D-glucanases (app. 50 IU/mL) and total cellulases (app. 9 IU/mL), whereas the medium with peptone and sodium carboxymethyl cellulose stimulated activity of exo-1,4-β-D-glucanases (33 IU/mL). The expression of cellulases reached its maximum within 96–144 hours, and the optimum pH is 3,7. Thermal treatment at 30 °C for 60 minutes activated endo-1,4-β-D-glucanases and total cellulases, while exo-1,4-β-D-glucanases activity was enhanced following 40 °C treatment. In total, the cellulases complex (300 IU/g) saccharified untreated cellulose by 38 % in 48 hours. Concentrate with filter paper activity 100 IU/g is the more balanced enzyme-substrate ratio (2 %), which allows prolonging the saccharification process that will have a positive effect on the cost of the final product.

Keywords

• Cellulose
• endo-1,4-β-D-glucanases
• exo-1,4-β-D-glucanases
• Irpex lacteus
• saccharification
• thermostability