Cogeneration of cellobiose and glucose from pretreated wood and bioconversion to lactic acid: a kinetic study.
Samples of Eucalyptus globulus wood were subjected to sequential treatments of delignification and swelling, and the solid residues were hydrolysed with a cellulase complex deficient in beta-glucosidase activity. In experiments carried out at 45 degrees C, the highest cellulose conversion (61.9%) was achieved in media containing 28 filter paper units/g using a liquor/solid ratio of 30 g/g. Models for the generation of cellobiose and glucose were developed assuming two sequential reactions (conversion of cellulose into cellobiose and hydrolysis of cellobiose to glucose) with end-product that results in competitive inhibition. Selected regression parameters were correlated with the operational conditions by means of empirical models (including linear and interaction terms) and a generalized calculation procedure that allows a close reproduction of data and shows a satisfactory ability for quantitative predictions was developed. Further experiments were carried out to study the bioconversion of hydrolysates by Lactobacillus delbrueckii into lactic acid. The kinetic modelling of the fermentation stage allowed a close interpretation of the experimental data.
Moldes
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Department of Chemical Engineering, University of Vigo (Campus Orense), Las Lagunas, 32004 Orense, Spain.
Alonso
J L
JL
Parajó
J C
JC