A comparison of various lignin-extraction methods to enhance the accessibility and ease of enzymatic hydrolysis of the cellulosic component of steam-pretreated poplar.

摘要: Current single-stage delignification-pretreatment technologies to overcome lignocellulosic biomass recalcitrance are usually achieved at the expense of compromising recovery polysaccharide components, particularly hemicellulose fraction. One way enhance overall sugar is tailor an efficient two-stage pretreatment that can pre-extract more labile component before subjecting cellulose-rich residual material a second-stage delignification process. Previous work had shown mild steam could recover >65% from poplar while limiting acid-catalysed condensation lignin. This potentially allowed for subsequent lignin extraction using various solvents produce accessible cellulosic substrate. A approach and/or solvent was assessed its ability separate and wood chips providing fraction be readily hydrolysed by cellulase enzymes. An initial steam-pretreatment stage performed over range temperatures (160–200 °C) equivalent severity factor 3.6. higher temperature 190 °C applied shorter residence time 10 min effectively solubilized recovered 75% enhancing [deep eutectic (DES), ethanol organosolv, soda/anthraquinone (soda/AQ) or hydrotrope] extract in second stage. When treatments were compared, DES treatment (lactic acid betaine) 130 °C, removed comparable amounts with selectivity than did soda/AQ organosolv pretreatments 170 °C. However, substrates obtained after showed highest cellulose accessibility, as measured Simon’s staining technique. They also most susceptible enzymatic hydrolysis. The varied their solubilize steam-pretreated hydrolysis resulting fractions. Although selective extracting substrates, post disrupted structure greater extent ease