Abstract

Palm kernel cake (PKC) and vegetable wastes were used as a fermentation substrate for the evaluation of cellulase activity secreted by Bacillus sp. In the current work, PKC and vegetable wastes were used as substrates in order to reduce the cost of cellulase production. The aim of this study was to determine the cellulase activity by Bacillus sp. on lignocellulosic materials mainly on different sizes of PKC and vegetable wastes. Besides that, pH, temperature, and inocula concentrations will also being tested for the optimum reaction of Bacillus sp. on the substrates. The PKC that were used can be divided into two types which are raw PKC and defatted PKC that had undergone Soxhlet oil removal. The results shown raw PKC, defatted PKC and vegetable wastes substrates have highest cellulase activity at 2.65 FPU/ml, 7.73 FPU/ml and 85.48 FPU/ml respectively. The optimum pH and incubation temperature for cellulase activity of Bacillus sp. was pH 4 and 50°C respectively. Bacillus concentrations of 2 x 105 cells/ml and 2 x 106 cells/ml, inoculated on PKCs and vegetable wastes produced the highest bacterial cellulases respectively. PKC with the particle size of 500μm was the most effective in producing higher cellulase activity likewise for larger particle size, of 1mm for vegetable wastes. From this study, Bacillus sp. holds the potential of converting lignocellulosic materials into products of commercial and industrial values such as glucose and other biofuels.