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Table 2 Quantification of the main components (total lignin, xylose and glucose) of eucalyptus bark (HGU an EG clones) after hot water extraction and each pretreatment step

From: Effects of pretreatment on morphology, chemical composition and enzymatic digestibility of eucalyptus bark: a potentially valuable source of fermentable sugars for biofuel production – part 1

Treatment   Cell-wall components (%)
Liquor fraction   Monosaccharides  
5-HMF (mg/g bark) Total lignin Xylose Glucose Treatment yield*
  EG HGU EG HGU EG HGU EG HGU EG HGU
Hot Water - - 25.1 ± 0.3 27.1 ± 0.6 15.0 ± 0.8 12.0 ± 0.2 41.5 ± 10.1 54.5 ± 11.7 100,0 100,0
Acid 1% 0.20 ± 0.05 0.23 ± 0.03 32.0 ± 0.3 32.0 ± 0.4 3.3 ± 0.5 4.2 ± 1.0 54.8 ± 14.0 47.2 ± 5.4 92,9 64,0
Acid 1% + NaOH 0.25% 0.03 ± 0.01 0.03 ± 0.01 30.7 ± 2.2 22.3 ± 0.6 2.4 ± 0.3 3.1 ± 0.4 58.6 ± 14.3 63.2 ± 1.6 88,2 63,1
Acid 1% + NaOH 0.5% - - 28.1 ± 0.3 22.6 ± 1.4 1.9 ± 0.2 2.7 ± 0.5 64.9 ± 6.1 66.5 ± 10.6 82,9 63,0
Acid 1% + NaOH 1% - - 23.9 ± 0.2 18.3 ± 0.3 1.6 ± 0.3 2.5 ± 0.3 66.5 ± 10.5 72.2 ± 10.7 78,7 59,2
Acid 1% + NaOH 2% - - 17.0 ± 0.2 13.0 ± 0.2 1.5 ± 0.5 1.7 ± 0.4 68.9 ± 3.3 73.4 ± 3.0 64,3 52,9
Acid 1% + NaOH 4% - - 14.7 ± 0.2 11.6 ± 0.1 1.8 ± 0.2 1.4 ± 0.2 75.8 ± 6.7 81.15 ± 1.5 66,7 54,2
NaOH 4% - - 19.3 ± 0.3 18.4 ± 0.6 12.0 ± 3.3 13.3 ± 3.8 56.1 ± 17.0 61.8 ± 12.3 73,1 63,4
  1. Amounts are expressed in percentage of dry matter.
  2. *Treatment yield (%) is calculated based on glucose losses (as a percentage of dry mass) during each pretreatment step, considering the initial amount in a hot water extracted sample. For samples submitted to a double-step pretreatment we considered the losses from acid plus alkaline steps.