Efficiency of Lignocellulolytic Extracts from Thermotolerant Strain Fomes sp. EUM۱: Stability and Digestibility of Agricultural Wastes

Production of lignocellulolytic enzymes by the thermotolerant Fomes sp. EUM۱ was determined in solid cultures using corn stover (CS) as a sole substrate or supplemented with ۲۰ % wheat bran (CS+WB). This supplementation increased (P< ۰.۰۵) enzymatic activity per gram of initial dry matter (gdm) for xylanases and cellulases: ۱۶۰ IU g dm-۱ and ۳۷ IU g dm-۱, respectively; while laccases reached a similar yield (۳.۳ IU g dm-۱) for both cultures. Nevertheless, laccases showed different stability patterns at ۳۹°C and pH ۶: half-life time (t½) was doubled in extracts from CS+WB (۲۳.۵ h); whereas t½ for the other enzymes from both cultures showed no difference. Both extracts by Fomes sp. EUM۱ and a commercial enzymatic product were used on forages: corn stover, (CS), sugarcane bagasse (SCB), and alfalfa hay (AH). The fractional rate of gas production (FR; ml g-۱ h-۱) increased (P< ۰.۰۵) at ۹ hours in CS compared to the sample without enzymes. The use of any enzymes favoured higher maximum gas volume (Vm; h-۱) on SCB. The in vitro digestibility (IVD) of CS after using the commercial product was ۱۲% higher, while our extracts from CS and CS+WB showed ۱۶ and ۲۱% improvements (P< ۰.۰۵), respectively, suggesting a higher specificity of these enzymes produced on the same substrate (CS). In addition to the proven stability, the versatility of extracts from CS and CS+WB was confirmed by the increase in IVD values for SCB (up to ۱۰۰%) in relation to the control without enzymes.

کلیدواژه ها:

Enzymatic extracts ، Fungal thermotolerance ، in vitro gas production ، Solid state cultures