Optimization of Laccase Production from Penicillium sp. LX/08 for Biodelignification of Ramie (Boehmeria nivea L. Gaud)

Abstract

Ramie solid waste as chips can be used as raw material for pulp. Ligninolytic enzymes of laccase widely used for pretreatment of the pulping process of ramie chips by biodelignification using laccase produced by Penicillium sp. LX/08 has been done. This study aims to obtain optimal concentrations of lignin and CuSO4 as enzyme inducers to increase laccase production from Penicillium sp. LX/08 during biodelignification process and its effect on the quality of ramie pulp. The biodelignification process of ramie chips was carried out by solid state fermentation (SSF) method with six days incubation time. Two inducer type treatment factors (CuSO4 and lignin), and variations in the concentration of each lignin (0.25 g/L, 0.5 g/L, 0.75 g/L) and CuSO4 (0.25 mM, 0.5 mM, 0.75 mM) were investigated in this study. The pulping process was carried out by the soda process in a digester under conditions: 12% active alkaline, temperature of 165°C for 3.5 hours. The results showed that 0.75 mM and 0.5 g/L of lignin were the optimal concentrations which could increase the laccase activity of Penicillium sp. LX/08 by 343 U/L and 25,8 U/L, respectively. The quality of ramie pulp showed a decrease in Kappa Number of 9,34% with an increase in pulp yield to 55,43%. Based on these results, the pretreatment method using laccase produced by Penicillium sp. LX/08 can assist the pulping process of ramie.