The research was conducted to study the growth characterization of Trichoderma reesei, the degradability of mannan polysaccharides from Palm Kernel Cake (PKC) with different concentrations of fungi and thickness of the PKC medium, as well as the improvement of the nutritive value of palm kernel cake. Experiment 1 was to study the growth characterization of Trichoderma reesei, and Experiment 2 was conducted using concentrations of fungi (104, 105, and 106 CFU per cc) and thickness of the PKC medium (1, 2, and 3 cm). The research used a completely randomized design with factorial 3 x 3. The treatments resulted in significant (P
