Two-stage fractionation of sugarcane bagasse by autohydrolysis and glycerol organosolv delignification in a lignocellulosic biorefinery concept

Two‐step fractionation of Pinus radiata by autohydrolysis and organosolv delignification for enzymatic hydrolysis

“…The EOL recovered by acid precipitation from black liquor of ORG varied between 2.2 and 8.1 g per 100 g P. radiata (Table ). The recovery of lignin during ORG depended on the conditions of the previous AH step, because this pretreatment produces changes in lignin which can affect the delignification step, as previously mentioned . For this reason, the lignin recovery was reduced from 5.7 to 2.2 g when the severity factor of AH was increased from S 0 = 2.95 to S 0 = 4.60 in autocatalyzed conditions.…”

“…The recovery of lignin during ORG depended on the conditions of the previous AH step, because this pretreatment produces changes in lignin which can affect the delignification step, as previously mentioned. 32 For this reason, the lignin recovery was reduced from 5.7 to 2.2 g when the severity factor of AH was increased from S 0 = 2.95 to S 0 = 4.60 in autocatalyzed conditions. This recovery of lignin is related to the DD, and therefore the quantity of lignin after the organosolv step was higher in acid-catalyzed than in autocatalyzed conditions.…”

“…55,56 The higher lignin content in pretreated solids is related to its difficulty of elimination during ORG owing to the lignin recondensation produced in the AH step. 32,49,57 When the highest severity factor in the AH step is employed (S 0 = 4.60), a lignin content of 32% is achieved due to a limited DD of 43%, and the enzymatic hydrolysis yield of pretreated solid drops to 4% (AH 190 -ORG A,185 ). Note that the raw material employed in this study is a softwood, which presents a high content of guaiacyl (G) units in the lignin.…”

“…[22][23][24] This sequential pretreatment has been studied for different lignocellulosic materials such as E. globulus wood, 25 olive tree trimmings, 15 Miscanthus switchgrass, 20 corn stover, 26 Eucommia ulmoides wood, 16 elm, 17 rice straw, 17,19 barley straw, 27 wheat straw, [28][29][30] and sugarcane bagasse. 14,[31][32][33] These works show the current interest in this pretreatment to achieve the fractionation of agricultural wastes and woody materials and allow the utilization of the separated fractions in subsequent steps, such as enzymatic hydrolysis. However, the use of softwood as raw material in this type of sequential pretreatment is limited.…”

“…This pretreatment can be performed without or with catalyst, either acidic (sulfuric or hydrochloric acid), basic (sodium hydroxide) or neutral (magnesium chloride) . This sequential pretreatment has been studied for different lignocellulosic materials such as E. globulus wood, olive tree trimmings, Miscanthus switchgrass, corn stover, Eucommia ulmoides wood, elm, rice straw, barley straw, wheat straw, and sugarcane bagasse . These works show the current interest in this pretreatment to achieve the fractionation of agricultural wastes and woody materials and allow the utilization of the separated fractions in subsequent steps, such as enzymatic hydrolysis.…”