Pretreatment of pressed pericarp fibers (PPF) using alcohols as solvent to increase the accessibility of cellulose for cellulase production

Abstract

Organosolvents such as methanol, ethanol, propanol, ethylene glycol, polyethylene glycol, and glycerol, representing alcohols of different physical and chemical properties, were used to pre-treat the pressed pericarp fiber (PPF) to improve its susceptibility towards enzymatic hydrolysis. Experimental studies were carried out with 5 g of PPF, treated with 65% (w/w) alcohol solution, at high temperature (180°C) and pressure (10 bar N2). The performance of different alcohols pretreatment on PPF varied in term of lignin removal (% w/w), cellulose retained (% w/w), and hydrolysis (% w/w). Pretreatment with aliphatic propanol showed the highest lignin removal (53.18%) from PPF, leaving more accessible cellulose; followed by ethanol (48.18%), methanol (44.55%), polyethylene glycol (43.18%), ethylene glycol (40%), glycerol (25.46%), and water (18.18%). Generally, these results were in accordance to Hildebrand solubility parameters, in which the solubility of lignin in solvents increased when the Hildebrand parameter of solvent neared to the value of eleven. Propanol-treated-PPF also showed the highest hydrolysis (46.16%), which was confirmed by the release of more accessible cellulose after the pretreatment. © 2012 The Korean Society for Applied Biological Chemistry.