Inhibitory Effect of Inorganic Salts Residuals on Cellulase Kinetics in Biofuel Production from Lignocellulose Biomass

Biorefining process has the goal to convert lignocellulose biomass to biofuels and value-added products and to reduce burning activities of agricultural wastes after harvesting seasons. Pretreatment of lignocellulose biomass by using inorganic salt has been demonstrated to be an efficient method to improve process productivity, yet its efficiency is inhibited by salt residues in hydrolysis. In this study, the mechanisms of inhibitory effects caused by inorganic salts, NaCl and KCl, on kinetic activities of commercial cellulase were revealed using Michaelis-Menten model. Three different types of cellulose and lignocellulose substrates, CMC, Avicel, and sugarcanes bagasse, were enzymatic hydrolyzed. Using Lineweaver-Burk plot, the results showed that the inhibitory effect of KCl and NaCl residues were non-competitive and mixed inhibition, respectively. Due to their inhibitory effect, inorganic salt residues reduced reducing sugar yields released from CMC and Avicel, however, the yield obtained from sugarcanes bagasse increased for 1.51 fold when adding 1.0 M NaCl. The finding in this research suggested the alternative method to use sugarcane bagasse for biofuel conversion and reduction of agricultural combustion.

I. Introduction

Due to agricultural activities, large amounts of agricultural wastes are left unused in fields in every harvesting seasons. Therefore, these residues are burned to prepare plantation fields before starting next plantation seasons. In case of sugarcane processing industries in developing countries, the harvesting process engages with on-field burning of sugarcane plants because burned plants are easier to cut and collected in piles than fresh plants. Such these scenario, air pollution is getting worse in worldwide scale, especially PM2.5 and PM10 particles, which are hazardous particles to human respiratory tracts [1], [2]. Thus, the circular economy concept has been become a focused research and implemented in industrial sectors.