Biomass Conversion and Biorefinery

, Volume 4, Issue 2, pp 77–86

Effect of hemicellulose liquid phase on the enzymatic hydrolysis of autohydrolyzed Eucalyptus globulus wood

Original Article

DOI: 10.1007/s13399-013-0093-3

Cite this article as:
Romaní, A., Ruiz, H.A., Pereira, F.B. et al. Biomass Conv. Bioref. (2014) 4: 77. doi:10.1007/s13399-013-0093-3

Abstract

In this work, Eucalyptus globulus wood was pretreated under non-isothermal autohydrolysis process at 210, 220, and 230 °C, obtaining a pretreated solid with high cellulose content and a hemicellulosic liquid phase (HLP) containing mainly xylose, acetic acid, furfural, xylooligosaccharides, and phenolic compounds. The maximum concentration of xylooligosaccharides (8.97 g/L) and phenolic compounds (2.66 g/L) was obtained at 210 and 230 °C, respectively. To evaluate the effect of HLP addition on the enzymatic hydrolysis using unwashed pretreated solid as substrate, different proportions of HLP were studied. Also, in order to use the whole slurry on enzymatic hydrolysis, the supplementation of xylanases was evaluated. Glucose concentration of 107.49 g/L (corresponding to 74.65 % of conversion) was obtained using pretreated solid at 220 °C liquid/solid ratio (LSR) of 4 g/g and enzyme solid ratio (ESR) of 25 FPU/g—without the addition of HLP. Thus, it was shown that the unwashed pretreated solids are susceptible to enzymatic hydrolysis contributing to reduce operational cost (water consumption). Additionally, the influence of the inhibitory compounds in the HLP was shown to affect the enzymatic hydrolysis. Results indicated that 82.52 g/L of glucose (59.37 % of conversion) was obtained, using 100 % of HLP at LSR of 4 g/g and ESR of 16 FPU/g at 210 °C of pretreated solid. However, a positive effect was shown on the enzymatic hydrolysis when the xylanases were added using 100 % of HLP, increasing to 35 and 27 % in the glucose production with respect to whole slurry without addition of xylanases.

Keywords

Enzymatic hydrolysis Hydrothermal process Whole-slurry material Hemicellulosic liquid phase Biorefinery Inhibitors 

Abbreviations

CGC96

Cellulose to glucose conversion at 96 h

CGCmax

Cellulose-to-glucose conversion predicted for an infinite reaction time (%)

CGCt

Cellulose-to-glucose conversion achieved at time (%)

DP

Degree of polymerization

EGW

Eucalyptus globulus wood

ESR

Enzyme to solid ratio (FPU/g of solid)

FPU

Filter paper unit

G96h

Glucose concentration at 96 h

Gn

Glucan of pre-treated solids (%) on dry basis

Gpot

Potential glucose (g/L)

Gt

Concentration of glucose achieved at time (g/L)

HLP

Hemicellulosic liquid phase

HMF

Hydroxymethylfurfural

HPLC

High-performance liquid chromatography

KL

Klason lignin on dry basis

LSR

Liquid to solid ratio (grams of liquid/gram of solid on dry basis)

R2

Coefficient of determination

S0

Severity

SY

Solid yield on dry basis

T

Enzymatic hydrolysis time (h)

T(t)

Temperature at time (°C)

t1/2

Time needed to reach CGCmax/2 (h)

TMAX

Minimum temperature achieved on a given hydrothermal treatment

TREF

Reference temperature (°C)

UI

Unit international

Ρ

Density of the hydrolysis enzymatic medium (g/L)

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Aloia Romaní
    • 1
  • Héctor A. Ruiz
    • 1
    • 2
  • Francisco B. Pereira
    • 1
  • Lucília Domingues
    • 1
  • José A. Teixeira
    • 1
  1. 1.IBB—Institute for Biotechnology and Bioengineering, Centre of Biological EngineeringUniversity of MinhoBragaPortugal
  2. 2.Food Research Department, School of ChemistryAutonomous University of CoahuilaSaltilloMexico

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