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1.
Pretreatment of Rice Straw by a Hot-Compressed Water Process for Enzymatic Hydrolysis 总被引:1,自引:0,他引:1
Guoce Yu Shinichi Yano Hiroyuki Inoue Seiichi Inoue Takashi Endo Shigeki Sawayama 《Applied biochemistry and biotechnology》2010,160(2):539-551
Hot-compressed water (HCW) is among several cost-effective pretreatment processes of lignocellulosic biomass for enzymatic
hydrolysis. The present work investigated the characteristics of HCW pretreatment of rice straw including sugar production
and inhibitor formation in the liquid fraction and enzymatic hydrolysis of pretreated material. Pretreatment was carried out
at a temperature ranging from 140 to 240 °C for 10 or 30 min. Soluble oligosaccharides were found to constitute almost all
the components of total sugars in the liquid fraction. The maximal production of total glucose at 180 °C and below accounted
for 4.4–4.9% of glucan in raw material. Total xylose production peaked at 180 °C, accounting for 43.3% of xylan in raw material
for 10-min pretreatment and 29.8% for 30-min pretreatment. The production of acetic acid increased at higher temperatures
and longer treatment time, indicating more significant disruption of lignocellulosic structure, and furfural production achieved
the maximum (2.8 mg/ml) at 200 °C for both 10-min and 30-min processes. The glucose yield by enzymatic hydrolysis of pretreated
rice straw was no less than 85% at 180 °C and above for 30-min pretreatment and at 200 °C and above for 10-min pretreatment.
Considering sugar recovery, inhibitor formation, and process severity, it is recommended that a temperature of 180 °C for
a time of 30 min can be the most efficient process for HCW pretreatment of rice straw. 相似文献
2.
Bin Guo Yuanhui Zhang Guo Yu Won-Heong Lee Yong-Su Jin Eberhard Morgenroth 《Applied biochemistry and biotechnology》2013,169(4):1069-1087
The focus of this work was to develop a combined acid and alkaline hydrothermal pretreatment of lignocellulose that ensures high recovery of both hexose and pentose. Dilute sulfuric acid and lime pretreatments were employed sequentially. Process performance was optimized in terms of catalyst concentration, retention time, and temperature using response surface methodology. Medium operational conditions in the acid stage and harsh conditions in the alkaline stage were desirable with optimal performance at 0.73 wt% H2SO4, 150 °C, 6.1 min in the first stage, and 0.024 g lime/g biomass, 202 °C, 30 min in the second stage. In comparison to single-stage pretreatments with high recovery of either glucose or xylose, two-stage process showed great promises with >80 % glucose and >70 % xylose recovery. In addition, the method greatly improved ethanol fermentation with yields up to 0.145 g/g Miscanthus, due to significantly reduced formation of inhibitory by-products such as weak acids, furans, and phenols. Supplementing biomimetic acids would further increase glucose yield by up to 15 % and xylose yield by 25 %. 相似文献
3.
A novel process using chemical, thermal, and enzymatic treatment for conversion of hulled barley into fermentable sugars was
developed. The purpose of this process is to convert both lignocellulosic polysaccharides and starch in hulled barley grains
into fermentable sugars simultaneously without a need for grinding and hull separation. In this study, hulled barley grains
were treated with 0.1 and 1.0 wt.-% sulfuric acid at various temperatures ranging from 110 to 170 °C in a 63-ml flow-through
packed-bed stainless steel reactor. After sulfuric acid pretreatment, simultaneous conversion of lignocellulose and starch
in the barley grains into fermentable sugars was performed using an enzyme cocktail, which included α-amylase, glucoamylase,
cellulase, and β-glucosidase. Both starch and non-starch polysaccharides in the pre-treated barley grains were readily converted
to fermentable sugars. The treated hulled barley grains, including their hull, were completely hydrolyzed to fermentable sugars
with recovery of almost 100% of the available glucose and xylose. The pretreatment conditions of this chemical, thermal, and
enzymatic (CTE) process for achieving maximum yield of fermentable sugars were 1.0 wt.% sulfuric acid and 110 °C. In addition
to starch, the acid pretreatment also retained most of the available proteins in solid form, which is essential for subsequent
production of fuel ethanol and high protein distiller’s dried grains with solubles co-product. 相似文献
4.
In scale-up, the potential of ethanol production by dilute sulfuric acid pretreatment using corncob was investigated. Pretreatments were performed at 170 °C with various acid concentrations ranging from 0% to 1.656% based on oven dry weight. Following pretreatment, pretreated biomass yield ranged from 59% to 67%. More than 90% of xylan was removed at 0.828% of sulfuric acid. At same pretreatment condition, the highest glucose yield obtained from pretreated biomass by enzymatic hydrolysis was about 76%, based on a glucan content of 37/100 g. In hydrolysate obtained by pretreatment, glucose concentration was low, while xylose concentration was significantly increased above 0.368% of sulfuric acid. At 1.656% of sulfuric acid, xylose and glucose concentration was highest. In subsequent, fermentation with hydrolysate, maximal ethanol yield was attained after 24 h with 0.368% of sulfuric acid. The fermentation efficiency of hydrolysate obtained by enzymatic hydrolysis reached a maximum of 75% at an acid charge of 0.368%. 相似文献
5.
Sugar cane bagasse was hydrolyzed under different concentrations of hydrochloric acid (2–6%), reaction times (0–300 min),
and temperatures (100–128°C). Sugars obtained (xylose, glucose, arabinose, and glucose) and deg-radation products (furfural
and acetic acid) were determined. Based on the Saeman model and the two-fraction model, kinetic parameters for predicting
these compounds in the hydrolysates were developed. The influence of temperature was studied using the Arrhenius equation.
The optimal conditions selected were 128°C, 2% HCl, and 51.1 min. Using these conditions, 22.6g xylose/L, 3.31 garabinose/L,
3.77 g glucose/L, 3.59 g acetic acid/L, and 1.54 g furfural/L were obtained. 相似文献
6.
Mauricio P. de Paula Talita M. Lacerda Márcia D. Zambon Elisabete Frollini 《Cellulose (London, England)》2012,19(3):975-992
The present work is inserted into the broad context of the upgrading of lignocellulosic fibers. Sisal was chosen in the present
study because more than 50% of the world’s sisal is cultivated in Brazil, it has a short life cycle and its fiber has a high
cellulose content. Specifically, in the present study, the subject addressed was the hydrolysis of the sisal pulp, using sulfuric
acid as the catalyst. To assess the influence of parameters such as the concentration of the sulfuric acid and the temperature
during this process, the pulp was hydrolyzed with various concentrations of sulfuric acid (30–50%) at 70 °C and with 30% acid
(v/v) at various temperatures (60–100 °C). During hydrolysis, aliquots were withdrawn from the reaction media, and the solid
(non-hydrolyzed pulp) was separated from the liquid (liquor) by filtering each aliquot. The sugar composition of the liquor
was analyzed by HPLC, and the non-hydrolyzed pulps were characterized by viscometry (average molar mass), and X-ray diffraction
(crystallinity). The results support the following conclusions: acid hydrolysis using 30% H2SO4 at 100 °C can produce sisal microcrystalline cellulose and the conditions that led to the largest glucose yield and lowest
decomposition rate were 50% H2SO4 at 70 °C. In summary, the study of sisal pulp hydrolysis using concentrated acid showed that certain conditions are suitable
for high recovery of xylose and good yield of glucose. Moreover, the unreacted cellulose can be targeted for different applications
in bio-based materials. A kinetic study based on the glucose yield was performed for all reaction conditions using the kinetic
model proposed by Saeman. The results showed that the model adjusted to all 30–35% H2SO4 reactions but not to greater concentrations of sulfuric acid. The present study is part of an ongoing research program, and
the results reported here will be used as a comparison against the results obtained when using treated sisal pulp as the starting
material. 相似文献
7.
Xin-Xia Xue Jun-Hua Di Yu-Cai He Bing-Qian Wang Cui-Luan Ma 《Applied biochemistry and biotechnology》2018,185(1):42-54
In this study, carbohydrates (cellulose plus hemicellulose) in corncob were effectively converted furfuralcohol (FOL) via chemical–enzymatic catalysis in a one-pot manner. After corncob (2.5 g, dry weight) was pretreated with 0.5 wt% oxalic acid, the obtained corncob-derived xylose (19.8 g/L xylose) could be converted to furfural at 60.1% yield with solid acid catalyst SO4 2?/SnO2-attapulgite (3.6 wt% catalyst loading) in the water–toluene (3:1, v/v) at 170 °C for 20 min. Moreover, the oxalic acid-pretreated corncob residue (1.152 g, dry weight) was enzymatically hydrolyzed to 0.902 g glucose and 0.202 g arabinose. Using the corncob-derived glucose (1.0 mM glucose/mM furfural) as cosubstrate, the furfural liquor (48.3 mM furfural) was successfully biotransformed to FOL by recombinant Escherichia coli CCZU-A13 cells harboring an NADH-dependent reductase (SsCR) in the water-toluene (4:1, v/v) under the optimum conditions (50 mM PEG-6000, 0.2 mM Zn2+, 0.1 g wet cells/mL, 30 °C, pH 6.5). After the bioreduction for 2 h, FAL was completely converted to FOL. The FOL yield was obtained at 0.11 g FOL/g corncob. Clearly, this one-pot synthesis strategy shows high potential application for the effective synthesis of FOL. 相似文献
8.
Gil Garrote Herminia Domínguez Juan C. Parajó 《Applied biochemistry and biotechnology》2001,95(3):195-207
Milled corncob samples were mixed with water and heated to obtain a liquid phase containing oligosaccharides, sugars, and
acetic acid as main reaction products (autohydrolysis reaction). To hydrolyze the sugar oligomers to the correspondent monomers,
sulfuric acid was added to the autohydrolysis liquors to reach 0.5–2 wt% of solution, and the reaction media were heated at
101.5–135°C. With this operational procedure, sugar solutions suitable as fermentation media (containing xylose as the major
component) were obtained. The kinetics of the posthydrolysis step was characterized on the basis of experimental data concerning
the time courses of the concentrations of xylooligosaccharides, xylose, furfural, and acetic acid. The concentrations of other
reaction byproducts (glucose or arabinose) were also measured. 相似文献
9.
Beatriz Palmarola-Adrados Mats Galbe Guido Zacchi 《Applied biochemistry and biotechnology》2004,115(1-3):989-1002
Steam treatment of an industrial process stream, denoted starch-free wheat fiber, was investigated to improve the formation
of monomeric sugars in subsequent enzymatic hydrolysis for further bioconversion into ethanol. The solid fraction in the process
stream, derived from a combined starch and ethanol factory, was rich in arabinose (21.1%), xylose (30.1%), and glucose (18.6%),
in the form of polysaccharides. Various conditions of steam pretreatment (170–220°C for 5–30 min) were evaluated, and their
effect was assessed by enzymatic hydrolysis with 2 g of Celluclast + Ultraflo mixture/ 100 g of starch-free fiber (SFF) slurry
at 5% dry matter (DM). The highest overall sugar yield for the combined steam pretreatment and enzymatic hydrolysis, 52g/100
g of DM of SFF, corresponding to 74% of the theoretical, was achieved with pretreatment at 190°C for 10 min followed by enzymatic
hydrolysis. 相似文献
10.
Gong-Yuan Wei You-Jung Lee Yi-Joon Kim Il-Hyuck Jin Jai-Heon Lee Chung-Han Chung Jin-Woo Lee 《Applied biochemistry and biotechnology》2010,162(5):1471-1482
The production of fermentable sugars from rice hull was studied by dilute acid pretreatment and enzymatic saccharification.
Rice hull (15%, w/v) was pretreated by 1% (v/v) sulfuric acid at high temperature (120∼160 °C) for 15, 30, 45, and 60 min, respectively. The maximum sugar concentration
from rice hull in the prehydrolysate was obtained at 140 °C for 30 min, but the enzymatic saccharification yield from the
corresponding pretreated rice hull is not high. To another aspect, the maximum enzymatic saccharification yield was achieved
at 160 °C for 60 min, while the recovery of fermentable sugars was the poorest. To take account of fermentable sugars from
pretreatment and enzymatic saccharification, the maximum yield of sugars was obtained only when rice hull was treated at 140 °C
for 30 min. Under this condition, 72.5% (w/w) of all sugars generated from the raw material can be recovered. The kinetic study on the enzymatic saccharification of dilute
acid pretreated rice hull was also performed in this work by a modified Michaelis–Menten model and a diffusion-limited model.
After calculation by a linear and a non-linear regression analysis, both models showed good relation with the experimental
results. 相似文献
11.
In this study, samples of moso bamboo were hydrolyzed for textile fiber with oxalic acid under various process conditions. Saeman hydrolysis models were applied to predict the percentage of xylan remained in the substrate after pretreatment and the net xylose yield in the liquid stream. Kinetic constants for Saeman hydrolysis models were analyzed by an Arrhenius-type expansion which include activation energy and catalyst concentration factors. The result showed that the degradation activation energies of xylan and xylose were 97.27 and 136.38 kJ/mol, respectively. Then the kinetic of mathematical models were obtained. Furthermore, the reaction parameters of oxalic acid concentration (1–4 % w/w), reaction temperature (150–180 °C), and reaction time (5–60 min) were handled as a single parameter, combined severity, which ranged in the present study from 0.86 to 1.62. Using combined severity parameters, an optimal condition was achieved which was as the followings: oxalic acid 2.0 % w/w, 170 °C, and 20 min. Under these conditions, 2.3 g glucose/L and 13.65 g xylose/L were produced in the hydrolysate fraction, 54.1 % glucan and 10.8 % xylan were produced in the residue fraction. 相似文献
12.
Pretreatment has been regarded as the most efficient strategy for conversion of lignocellulosic biomass to fermentable sugars. In this work, sulfolane pretreatment was performed to break the intricate structure of shrub willow for inhabitation of the enzymatic accessibility to holocellulose. The effects of varying pretreatment parameters on enzymatic hydrolysis of shrub willow were investigated. It was found that sulfolane was more compatible with lignin instead of carbohydrate, and the loss of carbohydrate could be attributed to water and acid generated from sulfolane. The optimum conditions leading to maximal sugar recovery from enzymatic saccharification were confirmed. After pretreatment of shrub willow powder in sulfolane at 170 °C for 1.5 h with mass ratio of sulfolane to substrate of 5, the sugar release could reach 555 mg/g raw materials (352 mg glucose, 203 mg xylose) when combining 20 FPU cellulase, 20 CBU β-glucosidase, and 1.5 FXU xylanase, representing 78.2 % of glucose and 56.6 % of xylose in shrub willow. This enhanced enzymatic saccharification was due to delignification and removal of a proportion of hemicelluloses, as confirmed by X-ray diffraction analysis, scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis, gas chromatography, and ionic chromatography. Thus, these studies prove sulfolane pretreatment to be an effective and promising approach for biomass to biofuel processing. 相似文献
13.
K. C. Patrick Lee Millicent Bulls John Holmes John W. Barrier 《Applied biochemistry and biotechnology》1997,66(1):1-23
Because of the recalcitrant nature of lignocellulosic materials, it is important to pretreat the biomass in order to obtain
a suitable material for the bioconversion. In this study, two different types of pretreatments were performed. The first experiment
used a 2-gal Parr reactor operated at 140, 150,160, and 170‡C with sulfuric acid concentrations varying from 0.5 to 2%. A
second pretreatment was performed with a two-stage low-temperature process. The first-stage pretreatment was performed at
100 or 120‡C with sulfuric acid concentrations of 0.5, 2, and 5% followed by a secondstage pretreatment at 120‡C with 2% acid
concentration. The best residues for enzymatic hydrolysis and simultaneous saccharification and fermentations (SSF) came from
the higher temperature pretreatment with the Parr reactor. However, a large portion of the xylose fraction was degraded to
furfural and glucose was degraded to HMF. On the contrary, the two-stage low temperature pretreatment resulted in a very low
percentage of xylose degradation, and no glucose degradation. The residues from this two-stage pretreatment performed satisfactorily
toward the production of ethanol by SSFs. This study discusses the results obtained from these experiments. 相似文献
14.
Chinnadurai Karunanithy Kasiviswanathan Muthukumarappan 《Applied biochemistry and biotechnology》2010,162(1):264-279
Pretreatment is being the first and most expensive step, it has pervasive impacts on all other steps in overall conversion
process. There are several pretreatment methods using physical, chemical, and biological principles which are under various
stages of investigation. Extrusion can be used as one of the physical pretreatment methods towards biofuel production. The
objective of this study was to evaluate the effect of barrel temperature and screw speed on sugar recovery from corn stover,
to select a suitable enzyme combination and its ratio. Corn stover was pretreated in a single screw extruder with five screw
speeds (25, 50, 75, 100, and 125 rpm) and five barrel temperatures (25, 50, 75, 100, and 125 °C). In order to select a suitable
enzyme combination and ratio, different levels of cellulase and β-glucosidase, multienzyme complex and β-glucosidase were
used during saccharification of pretreated corn stover. From the statistical analysis, it was found that screw speed and temperature
had a significant effect on sugar recovery from corn stover. Higher glucose, xylose, and combined sugar recovery of 75, 49,
and 61%, respectively, were recorded at 75 rpm and 125 °C. This pretreatment condition resulted in 2.0, 1.7, and 2.0 times
higher than the control sample using 1:4 cellulase and β-glucosidase combination. 相似文献
15.
Laura L. G. Fuentes Sarita C. Rabelo Rubens Maciel Filho Aline C. Costa 《Applied biochemistry and biotechnology》2011,163(5):612-625
The objective of this work was to determine the optimum conditions of sugarcane bagasse pretreatment with lime to increase
the enzymatic hydrolysis of the polysaccharide component and to study the delignification kinetics. The first stage was an
evaluation of the influence of temperature, reaction time, and lime concentration in the pretreatment performance measured
as glucose release after hydrolysis using a 23 central composite design and response surface methodology. The maximum glucose yield was 228.45 mg/g raw biomass, corresponding
to 409.9 mg/g raw biomass of total reducing sugars, with the pretreatment performed at 90°C, for 90 h, and with a lime loading
of 0.4 g/g dry biomass. The enzymes loading was 5.0 FPU/dry pretreated biomass of cellulase and 1.0 CBU/dry pretreated biomass
of β-glucosidase. Kinetic data of the pretreatment were evaluated at different temperatures (60°C, 70°C, 80°C, and 90°C),
and a kinetic model for bagasse delignification with lime as a function of temperature was determined. Bagasse composition
(cellulose, hemicellulose, and lignin) was measured, and the study has shown that 50% of the original material was solubilized,
lignin and hemicellulose were selectively removed, but cellulose was not affected by lime pretreatment in mild temperatures
(60–90°C). The delignification was highly dependent on temperature and duration of pretreatment. 相似文献
16.
Elizabeth Martin Julie Duke Mathew Pelkki Edgar C. Clausen Danielle Julie Carrier 《Applied biochemistry and biotechnology》2010,162(6):1660-1668
Liquidambar styraciflua L., also known as sweetgum, is an understory hardwood species that has widespread distribution in the southeast USA, especially in pine plantations. In addition to being a possible biorefinery feedstock, sweetgum contains shikimic acid, which is a precursor for the drug Tamiflu®. Sweetgum bark was extracted with 65 °C water and yielded 1.7 mg/g of shikimic acid, while sweetgum de-barked wood yielded 0.2 mg/g of shikimic acid. Because shikimic acid can be extracted with water, the coupling of the phytochemical hot water extraction with dilute acid pretreatment was examined. The addition of a 65 °C shikimic acid extraction step coupled to pretreatment with 0.98% H2SO4 at 130 °C for 50 min resulted in 21% and 17% increases in xylose percent recovery from bark and de-barked wood, respectively. These results indicate that, in addition to recovering a high value product, the 65 °C wash step also increases xylose recovery. 相似文献
17.
Andrei Jitianu John Doyle Glenn Amatucci Lisa C. Klein 《Journal of Sol-Gel Science and Technology》2010,53(2):272-279
Hybrid melting gels were prepared by a sol–gel process, starting with a mono-substituted siloxane and a di-substituted siloxane.
Methyl-modified melting gels were prepared using (a) methyltriethoxysilane (MTES) with dimethyldiethoxysilane (DMDES) and
(b) methyltrimethoxysilane (MTMS) together with dimethyldimethoxysilane (DMDMS). The gels with MTES–DMDES were prepared with
concentrations between 50–50 and 75–25 mol%. The gels with MTMS–DMDMS were prepared with concentrations between 50–50 and
70–30 mol%. For both systems, the consolidation temperature, after which the melting gel no longer softens, increased with
an increase in the amount of the mono-substituted siloxane, increasing from 135 to 160 °C for MTES–DMDES and increasing from
145 to 170 °C for MTMS–DMDMS. Coatings formed on mica substrates were about 1 mm thick, and showed no visible cracks. The
surfaces of the coatings were profiled using micro-Raman spectroscopy, which revealed that methyl groups were concentrated
at the surfaces of the films. All contact angles measured with water were greater than 90°. 相似文献
18.
Kim Sung Bae Um Byung Hwan Park Soon Chul 《Applied biochemistry and biotechnology》2001,91(1-9):81-94
The effect of pretreatment reagent and hydrogen peroxide on enzymatic digestibility of oak was investigated to compare pretreatment
performance. Pretreatment reagents used were ammonia, sulfuric acid, and water. These solutions were used without or in combination
with hydrogen peroxide in the percolation reactor. The reaction was carried out at 170°C for the predetermined reaction time.
Ammonia treatment showed the highest delignification but the lowest digestibility and hemicellulose removal among the three
treatments. Acid treatment proved to be a very effective method in terms of hemicellulose recovery and cellulose digestibility.
Hemicellulose recovery was 65–90% and digestibilities were >90% in the range of 0.01–0.2% acid concentration. In both treatments,
hydrogen peroxide had some effect on digestibility but decomposed soluble sugars produced during pretreatment. Unlike ammonia
and acid treatments, hydrogen peroxide in water treatment has a certain effect on hemicellulose recovery as well as delignification.
At 1.6% hydrogen peroxide concentration, both hemicellulose recovery and digestibility were about 90%, which were almost the
same as those of 0.2% sulfuric acid treatment. Also, digestibility was investigated as a function of hemicellulose removal
or delignification. It was found that digestibility was more directly related to hemicellulose removal rather than delignification. 相似文献
19.
Andrei Jitianu Kristin Lammers Georgia A. Arbuckle-Kiel Lisa C. Klein 《Journal of Thermal Analysis and Calorimetry》2012,107(3):1039-1045
Hybrid melting gels were prepared by a sol–gel process, starting with a mono-substituted siloxane and a di-substituted siloxane,
methyltrimethoxysilane (MTES) together with dimethyldimethoxysilane (DMDES). Five gel compositions were prepared with concentrations
between 50% MTES–50% DMDES and 75% MTES–25% DMDES (in mol.%). The consolidation temperature, the treatment temperature after
which the melting gel no longer softens, increased from 135 to 160 °C with a decrease in the amount of the mono-substituted
siloxane. The glass transition temperature, recorded with differential scanning calorimetry, decreased from −0.3 to −56.7 °C
with a decrease in the amount of the mono-substituted siloxane. When a sample was heat treated isothermally for 2 h at the
consolidation temperature, the glass transition temperature increased by about 15°, indicating further crosslinking of the
siloxane network. 相似文献
20.
Akarin Boonsombuti Apanee Luengnaruemitchai Sujitra Wongkasemjit 《Cellulose (London, England)》2013,20(4):1957-1966
Bioethanol produced from a conventional fermentation process using Saccharomyces cerevisiae utilizing pretreated and hydrolyzed corncob as a substrate was studied. It was found that the morphology of corncob was significantly changed after microwave-assisted alkali pretreatment was applied. An increase in the crystallinity index and surface area of the pretreated corncob was also observed. The highest total sugar concentration of 683.97 mg/g of pretreated corncob, or 45.60 g L?1, was obtained from the optimum pretreatment conditions of 2 % NaOH at 100 °C for 30 min in a microwave oven. Microwave-assisted alkali pretreatment was an efficient way to improve the enzymatic hydrolysis accessibility of corncob in a shorter amount of time and at a lower temperature, compared to other methods. 相似文献