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.
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.
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DOI：
10.1186/1754-6834-6-75
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发表时间：
2013-05-09
影响因子：
6.3
通讯作者：
Polikarpov I
中科院分区：
文献类型：
--
作者：
Lima MA;Lavorente GB;da Silva HK;Bragatto J;Rezende CA;Bernardinelli OD;Deazevedo ER;Gomez LD;McQueen-Mason SJ;Labate CA;Polikarpov I
近年来，对生物燃料日益增长的需求鼓励人们寻找不同来源的未充分利用的木质纤维素原料，这些原料的丰度足以用于可持续的生物燃料生产。很多注意力都集中在草的生物量上。然而，大量的木材残留物，如桉树树皮是可用的，代表了转化为生物乙醇的潜在来源。本文研究了两种桉树无性系巨桉（Eucalyptus grandis，EG）和杂交桉（Eucalyptus hybrid，E. grandis x urophylla（HGU）。测定酶消化率和总纤维素转化率，沿着对固体和液体组分组成的影响。树皮也进行了评估，使用傅里叶变换红外光谱（FTIR），固态核磁共振（NMR），X射线衍射，扫描电子显微镜（SEM）。组成分析表明，纤维素含量的增加，分别达到约81%和76%的葡萄糖的HGU和EG，使用两步处理用HCl 1%，然后用4%NaOH。木质素去除率分别为84%（HGU）和79%（EG），而半纤维素去除率分别为95%和97%（HGU和EG）。然而，当我们应用一步处理，用4%NaOH，较高的水解效率被发现后48小时的两个克隆，达到几乎100%的HGU和80%的EG，尽管较低的木质素和半纤维素的去除。总纤维素转化率从5%和7%增加到HGU的约65%和EG的59%。NMR和FTIR为木质素和半纤维素的去除提供了重要的见解，SEM研究揭示了预处理后细胞壁的非结构化以及木质素在纤维表面的迁移和沉淀，这解释了克隆的不同水解速率。结果表明，一步碱预处理提高了桉树皮的酶消化率。此外，本研究结合化学和物理方法，提供了一个更好的理解预处理对细胞壁的影响和影响酶消化率的因素，这种森林剩余物。
In recent years, the growing demand for biofuels has encouraged the search for different sources of underutilized lignocellulosic feedstocks that are available in sufficient abundance to be used for sustainable biofuel production. Much attention has been focused on biomass from grass. However, large amounts of timber residues such as eucalyptus bark are available and represent a potential source for conversion to bioethanol. In the present paper, we investigate the effects of a delignification process with increasing sodium hydroxide concentrations, preceded or not by diluted acid, on the bark of two eucalyptus clones: Eucalyptus grandis (EG) and the hybrid, E. grandis x urophylla (HGU). The enzymatic digestibility and total cellulose conversion were measured, along with the effect on the composition of the solid and the liquor fractions. Barks were also assessed using Fourier-transform infrared spectroscopy (FTIR), solid-state nuclear magnetic resonance (NMR), X-Ray diffraction, and scanning electron microscopy (SEM). Compositional analysis revealed an increase in the cellulose content, reaching around 81% and 76% of glucose for HGU and EG, respectively, using a two-step treatment with HCl 1%, followed by 4% NaOH. Lignin removal was 84% (HGU) and 79% (EG), while the hemicellulose removal was 95% and 97% for HGU and EG, respectively. However, when we applied a one-step treatment, with 4% NaOH, higher hydrolysis efficiencies were found after 48 h for both clones, reaching almost 100% for HGU and 80% for EG, in spite of the lower lignin and hemicellulose removal. Total cellulose conversion increased from 5% and 7% to around 65% for HGU and 59% for EG. NMR and FTIR provided important insight into the lignin and hemicellulose removal and SEM studies shed light on the cell-wall unstructuring after pretreatment and lignin migration and precipitation on the fibers surface, which explain the different hydrolysis rates found for the clones. Our results show that the single step alkaline pretreatment improves the enzymatic digestibility of Eucalyptus bark. Furthermore, the chemical and physical methods combined in this study provide a better comprehension of the pretreatment effects on cell-wall and the factors that influence enzymatic digestibility of this forest residue.
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影响因子：
2.4
作者：
MARTINEZ, AT;GONZALEZ, AE;HAW, JF
通讯作者：
HAW, JF
影响因子：
11.4
作者：
Emmel, A;Mathias, AL;Ramos, LP
通讯作者：
Ramos, LP
影响因子：
3.8
作者：
Donohoe, Bryon S.;Decker, Stephen R.;Vinzant, Todd B.
通讯作者：
Vinzant, Todd B.
影响因子：
11.4
作者：
Ferraz, A;Baeza, J;Freer, J
通讯作者：
Freer, J
影响因子：
3
作者：
FOCHER, B;MARZETTI, A;CARNITI, P
通讯作者：
CARNITI, P