Development of a generalized phenomenological model describing the kinetics of the enzymatic hydrolysis of NaOH-treated pine wood

Pinus pinaster wood samples were treated during 3 h with alkaline solutions (containing 1, 5.5, or 10 weight percent NaOH) at 100, 115, or 130‡C using liquor/wood ratios of 6, 8, or 10 g/g. The solid residues obtained in treatments were used as substrates for enzymatic hydrolysis. In the hydrolysis assays, the reaction time (in the range 0–48 h) was considered as an operational variable. The cellulose conversion achieved at the end of assays were highest for samples pretreated at high temperature and high alkali concentration using low liquor/wood ratios. The experimental results obtained in each hydrolysis trial were fitted to an empirical model based on the assumption that the cellulose contained in substrates was composed by two fractions having different susceptibility to hydrolysis. The kinetic parameters obtained for the various experiments performed were correlated with the operational variables by means of empirical, statistically significant equations, which provided a generalized interpretation of the process.