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Table 3 Quantification of soluble and Klason lignin of eucalyptus barks (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 Lignin content   
EG HGU Total lignin (%)
  Soluble (%) Klason (%) Soluble (%) Klason (%) EG HGU
Hot Water 1.7 ± 0.1 23.4 ± 0.6 2.9 ± 0.9 24.2 ± 0.5 25.1 ± 0.3 27.1 ± 0.6
Acid 1% 0.7 ± 0.1 31.3 ± 0.5 1.0 ± 0.3 31.0 ± 0.7 32.0 ± 0.3 32.0 ± 0.4
Acid 1% + NaOH 0.25% 0.5 ± 0.2 30.2 ± 1.5 0.6 ± 0.2 21.7 ± 0.8 30.7 ± 2.2 22.3 ± 0.6
Acid 1% + NaOH 0.5% 0.6 ± 0.2 27.5 ± 0.6 0.5 ± 0.2 22.1 ± 1.3 28.1 ± 0.3 22.6 ± 1.4
Acid 1% + NaOH 1% 0.6 ± 0.3 23.3 ± 0.5 0.7 ± 0.3 17.6 ± 0.6 23.9 ± 0.2 18.3 ± 0.3
Acid 1% + NaOH 2% 0.7 ± 0.1 16.3 ± 0.5 0.5 ±0.1 12.5 ± 0.5 17.0 ± 0.2 13.0 ± 0.2
Acid 1% + NaOH 4% 0.4 ± 0.2 14.3 ± 0.5 0.5 ± 0.2 11.1 ± 0.3 14.7 ± 0.2 11.6 ± 0.1
NaOH 4% 1.7 ± 0.5 17.6 ± 0.7 2.2 ± 0.6 16.2 ± 0.9 19.3 ± 0.3 18.4 ± 0.6
  1. Amounts expressed as percentage of dry matter.