Experimental Assessment on the Enzymatic Hydrolysis of Hydrothermally Pretreated Eucalyptus globulus Wood

Hydrothermal processing of Eucalyptus globulus wood was evaluated as a pretreatment for bioethanol manufacture, to assess the effects caused by the severity of wood solubilization, composition of liquors, and spent solid and suceptibility of substrates toward enzymatic hydrolysis. A factorial design was employed to assess the hydrolysis kinetics of spent solids. The liquor to solid ratio (6-20 g/g) and the enzyme to substrate ratio (8-28 FPU/g) were considered as independent variables. Generalized empirical models suitable for predicting glucose concentrations were developed. Using selected substrates and hydrolysis conditions (LSR = 6 g/g, ESR = 28 FPU/g), media containing more than 82 g glucose/L were obtained (with cellulose-to-glucose conversions of 75-80%), whereas cellulose-to-glucose conversions of 80-100% were obtained under a variety of experimental conditions.