Efficient extraction of bagasse hemicelluloses and characterization of solid remainder
Introduction
The plant fibrous material contains about 15–35% of hemicellulose, and most of the hemicelluloses are extracted during the pulping stage. Calorific value of the hemicellulose is 13.6 MJ/kg, which is half of the lignin (Li et al., 2014). The kraft process in the modern pulp and paper making industry typically burns the extracted hemicellulose for steam. This kind of hemicellulose is underutilized, which is a great waste of resources. The fossil resources nearly dried up at present, it is particularly important for hemicellulose efficient utilization.
The existing pre-extraction methods mainly include physical method, chemical method and biological method. In concrete terms, there are dilute acid extraction (Walton et al., 2010, Wang et al., 2012), hot water extraction (Krogell et al., 2013, Liu, 2010, Liu et al., 2012), steam explosion extraction (Martin-Sampedro et al., 2014), alkali extraction (Sun et al., 2013) and dilute acid steam explosion (Sabiha-Hanim et al., 2015). The process condition of dilute acid extraction is hard to control, and the pulping yield will be reduced by the hydrolysis of cellulose. The structure of cellulose will be disrupted during the steam explosion extraction. The operating cost of alkali extraction is high for the employment of alkali and acid adding for pH adjustment. The hot water extraction develops with the purpose of reducing cost and environmental pollution, and hydrolysis of hot water extracts can be combined with the separation of solid materials. Shorter reaction time, higher concentration acid and higher temperature will produce more xylose monomer (Feria et al., 2012). The membrane filtration used for concentrated extract can avoid the employment of high concentration acid (Amidon and Liu, 2009). The ideal environment of extraction of woody biomass and separation of aromatic substances was acid medium (Krawczyk et al., 2013). Benko et al. found that the hemicellulose extraction yield (HEY) increased with the increase of hot water extraction temperature, but the molecular weight of polysaccharides decreased, as well as the hemicellulose damage increased (Benko et al., 2007).
In the previous work we found that, adding alkali could achieve effective in neutralizing the acids released during the pretreatment process. It could reduce the degradation of cellulose and obtain high molecular weight of hemicellulose from the extracts. This paper mainly focused on the efficient hot water extraction of hemicellulose. To reduce the degradation of cellulose and obtain high molecular weight of hemicellulose from extracts, pH pre-corrected hot water pretreatment was developed by employing sodium hydroxide (3.9 mol/L). The response surface model was established to optimize the extraction process. The species composition and purity of hemicellulose extract (HE) was analyzed by HPLC. The characterization and cross section morphology of raw material and solid remainder was analyzed by FTIR and SEM.
Section snippets
Raw material and chemicals
Bagasse was provided by a local sugar refinery (Guangxi, China). The pulp Kappa number was 10.1 and brightness was 31.9% ISO. 3.9 mol/L sodium hydroxide was prepared for controlling the pH of the solution. Xylan was used as a representative of the hemicellulose component and was purchased from Aladdin (China). All assay reagents were obtained from Sigma (USA). All the other chemicals employed in this work were purchased from Chong Qing Kawahigashi Chemical Co., LTD. (China). All of the chemicals
Raw material composition analysis
The chemical composition of bagasse was previously analyzed by Ruiz (Ruiz et al., 2011), containing cellulose of 45.28%, lignin of 22.39%, hemicellulose of 22.13% and ash of 1.01%. The chemical composition of traditional hot-water extraction (TP) and hot water extraction (OP) of bagasse were shown in Table 2. It can be seen that, the HEY of TP and OP was 33.44% and 43.38%, respectively. The degradation of cellulose and lignin was 2.19% and 11.34% with TP and 1.81% and 10.94% with OP,
Conclusions
The new technology of adding sodium hydroxide to achieve pH pre-corrected in hot-water pretreatment has been proposed. It confirmed to be effective in neutralizing the acids released during the pretreatment. The degradation of cellulose or lignin can be reduced and high molecular weight of hemicellulose from extracts was obtained. The biggest balance between solid remainder and dissolved solid was obtained. Not only the yield of hemicellulose extract was improved, but the structure of residual
Acknowledgements
The authors are grateful for the National Natural Science Foundation of China (B061103), The Guangxi Natural Fund (2012GXNSFAA053023) & (2013GXNSFFA019005) & (2014GXNSFBA118060), and the Innovation Project of Guangxi Graduate Education (YCBZ2012003).
References (33)
- et al.
Water-based woody biorefinery
Biotechnol. Adv.
(2009) - et al.
Biorefinery process for production of paper and oligomers from Leucaena leucocephala K360 with or without prior autohydrolysis
Bioresour. Technol.
(2012) - et al.
Valorization of Leucaena leucocephala for energy and chemicals from autohydrolysis
Biomass Bioenergy
(2011) - et al.
Manufacture of fibrous reinforcements for biocomposites and hemicellulosic oligomers from bamboo
Chem. Eng. J.
(2011) - et al.
Combined membrane filtration and enzymatic treatment for recovery of high molecular mass hemicelluloses from chemithermomechanical pulp process water
Chem. Eng. J.
(2013) - et al.
Intensification of hemicellulose hot-water extraction from spruce wood in a batch extractor–effects of wood particle size
Bioresour. Technol.
(2013) - et al.
PH pre-corrected liquid hot water pretreatment on corn stover with high hemicellulose recovery and low inhibitors formation
Bioresour. Technol.
(2014) Woody biomass: Niche position as a source of sustainable renewable chemicals and energy and kinetics of hot-water extraction/hydrolysis
Biotechnol. Adv.
(2010)- et al.
A sustainable woody biomass biorefinery
Biotechnol. Adv.
(2012) - et al.
Varying the porous structure of polystyrene/divinylbenzene beads prepared by Ugelstads activated swelling technique and examining its reversed phase HPLC properties
J. Chromatogr. A
(2014)
Surface characterizations of bamboo substrates treated by hot water extraction
Bioresour. Technol.
Integration of a kraft pulping mill into a forest biorefinery: pre-extraction of hemicellulose by steam explosion versus steam treatment
Bioresour. Technol.
Xylan from corn cobs, a promising polymer for drug delivery: production and characterization
Bioresour. Technol.
Fractional purification and bioconversion of hemicelluloses
Biotechnol. Adv.
Fractionation of wheat and barley straw to access high-molecular-mass hemicelluloses prior to ethanol production
Bioresour. Technol.
Biorefinery valorization of autohydrolysis wheat straw hemicellulose to be applied in a polymer-blend film
Carbohydr. Polym.
Cited by (91)
Lignocellulosic biomass fertilizers: Production, characterization, and agri-applications
2024, Science of the Total EnvironmentTurning agricultural waste streams into biodegradable plastic: A step forward into adopting sustainable carbon neutrality
2024, Journal of Environmental Chemical EngineeringCellulose-based fertilizers for sustainable agriculture: Effective methods for increasing crop yield and soil health
2023, Industrial Crops and ProductsSelective separation of hemicellulose from poplar by hydrothermal pretreatment with ferric chloride and pH buffer
2023, International Journal of Biological Macromolecules
- 1
These authors contributed equally to this work.