Monosaccharide production from lignocellulosic biomasses via concentrated acid hydrolysis

Monosaccharides are valuable and versatile platform chemicals that can be obtained by hydrolyzing cellulose and hemicelluloses in lignocellulosic biomasses [1, 2, 3]. Hydrolysis with concentrated sulfuric acid as catalyst leads to 80% or higher monosaccharide yield. Only a low amount of by-products is formed [2, 3]. The hydrolysis acid must be removed prior to downstream processing of monosaccharides. Traditionally neutralization with Ca(OH)2 has been used. This results in high chemical consumption and generation of waste gypsum. In addition, fresh sulfuric acid is needed for every hydrolysis [2, 3]. In order to lower the chemical costs of the concentrated acid hydrolysis process, the hydrolysis acid should be recycled. This can be accomplished by using chromatography: the hydrolysates are fractionated into sulfuric acid fraction, monosaccharide fraction, and by-product fractions [2]. In this work, batchwise chromatographic fractionation of wood based concentrated acid lignocellulosic hydrolysates was studied. Effectiveness of the chromatographic purification was evaluated by investigating ethanol production from the purified monosaccharide solutions using S. cerevisiae.