Physical and Biophysical Pretreatment of Water Hyacinth Biomass for Cellulase Enzyme Production

F. Amriani, F. A. Salim, I. Iskandinata, D. Khumsupan and Z. Barta

Abstract
One practical way to control water hyacinth overgrowth due to eutrophication is by utilizing it as a substrate to produce cellulase. Water hyacinth was subjected to pretreatment to degrade lignin and improve microbes’ accessibility to cellulose. Physical and biophysical pretreatment methods were investigated. Biomass size reduction was performed in the physical pretreatment whereas white rot fungus (Ganoderma boninense) was used in the biophysical pretreatment. Cellulase-producing fungi, Aspergillus niger and Trichoderma reesei, were exploited in this study. Although lignin content was reduced by two-fold after the biophysical pretreatment, the maximum production of cellulase occurred when only the physical pretreatment was employed on the substrate. It may be because the higher apparent crystallinity of cellulose in physical pretreatment triggers more cellulase production compared to that in biophysical pretreatment. The maximum cellulase activity was found to be 1.035 IU mL–1 when water hyacinth was only physically pretreated.

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Keywords
cellulase, cellulose, pretreatment, Trichoderma reesei, water hyacinth