Microorganisms
T. reesei, T. viride, T. harzianum and T. virens were obtained from National Research Centre, Cairo, Egypt and maintained on potato dextrose agar. The slants were grown at 28 °C for seven days and stored at 4 °C.
Pretreatment of agricultural wastes
Wheat bran, date's seeds, grass and palm leaves were chosen as the sole nutrient source for solid-state fermentation (SSF). They dried in an oven at 80 °C for 24 h. The dried substrates were then milled in a commercial mill and sieved. The mean diameter of the dried substrates was 1.0 mm. The substrates were pretreated with 1.0 M NaOH at 121 °C and 15 psi pressure for 1 hr at the ratio of 1:10 (w/v) [23,24]. The pretreated materials were washed with tap water until the pH of the filtrate reached 7.0. The washed materials were dried at 60 °C overnight to constant weight and stored at room temperature for further use.