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1.
Pretreatment of corn fiber by pressure cooking in water 总被引:4,自引:0,他引:4
Joseph R. Weil Ayda Sarikaya Shiang-Lan Rau Joan Goetz Christine M. Ladisch Mark Brewer Rick Hendrickson Michael R. Ladisch 《Applied biochemistry and biotechnology》1998,73(1):1-17
The pretreatment of corn fiber using liquid water at temperatures between 220 and 260°C enhances enzymatic hydrolysis. This
paper describes the laboratory reactor system currently in use for cooking of corn fiber at temperatures ranging from 200
to 260°C. The corn fiber at approx 4.4% solid/liquid slurry was treated in a 2-L, 304 SS, Parr reactor with three turbine
propeller agitators and a Proportional-Integral-Derivative (PID), controller that controlled temperature within ±1°C. Heat-up
times to the final temperatures of 220, 240, or 260°C were achieved in 50 to 60 min. Hold time at the final temperature was
less than 10 s. A serpentine cooling coil, through which tap water was circulated at the completion of the run, cooled the
reactor’s contents to 180°C within 2 min after the maximum temperature was attained. Ports in the reactor’s head plate facilitated
sampling of the slurry and monitoring the pH. A continuous pH monitoring system was developed to help observe trends in pH
during pretreatment and to assist in the development of a base (2.0M KOH) addition profile to help keep the pH within the range of 5.0 to 7.0. Enzymatic hydrolysis gave 33 to 84% conversion
of cellulose in the pretreated fiber to glucose compared to 17% for untreated fiber. 相似文献
2.
Damo M. Yourchisin G. Peter Van Walsum 《Applied biochemistry and biotechnology》2004,115(1-3):1073-1086
This research quantified the enzymatic digestibility of the solid component and the microbial inhibition of the liquid component
of pretreated aspen wood and cornstover hydrolysates. Products of liquid hot water and carbonic acid pretreatment were compared.
Pretreatment temperatures tested ranged from 180 to 220°C, and reaction times were varied between 4 and 64 min. Both microbial
inhibition rates and enzymatic hydrolysis rates showed no difference between pretreatments containing carbonic acid and those
not containing no carbonic acid. Microbial inhibition increased as the reaction severity increased, but only above a midpoint
severity parameter of 200°C for 16 min. Both the rates and yields of enzymatic hydrolysis displayed an increase from the lowest
tested reaction severity to the highest tested reaction severity. 相似文献
3.
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
4.
Ballesteros Ignacio Oliva José Miguel Negro Maria José Manzanares Paloma Ballesteros Mercedes 《Applied biochemistry and biotechnology》2002,98(1-9):717-732
The olive pulp fraction contained in the residue generated in olive oil extraction by a two-step centrifugation process can
be upgraded by using the cellulose fraction to produce ethanol and recovering high value phenols (tyrosol and hydroxytyrosol).
Olive pulp was pretreated in a laboratory scale stirred autoclave at different temperatures (150–250°C). Pretreatment was
evaluated regarding cellulose recovery, enzymatic hydrolysis effectiveness ethanol production by a simultaneous saccharification
and fermentation process (SSF), and phenols recovery in the filtrate. The pretreatment of olive pulp using water at temperatures
between 200°C and 250°C enhanced enzymatic hydrolysis. Maximum ethanol production (11.9 g/L) was obtained after pretreating
pulp at 210°C in a SSF fed-batch procedure. Maximum hydroxytyrosol recovery was obtained in the liquid fraction when pretreated
at 230°C. 相似文献
5.
Tucker M. P. Farmer J. D. Keller F. A. Schell D. J. Nguyan Q. A. 《Applied biochemistry and biotechnology》1998,(1):25-35
Single-stage cocurrent dilute acid pretreatments were carried out on yellow poplar (Liriodendron tulipifera) sawdust using an as-installed and short residence time modified pilot-scale Sunds hydrolyzer and a 4-L bench-scale NREL
digester (steam explosion reactor). Pretreatment conditions for the Sunds hydrolyzer, installed in the NREL process development
unit (PDU), which operates at 1 t/d (bone-dry t) feed rate, spanned the temperature range of 160 – 210°C, 0.1 – 1.0% (w/w)
sulfuric acid, and 4-10-min residence times. The batch pretreatments of yellow poplar sawdust in the bench-scale digester
were carried out at 210 and 230°C, 0.26% (w/w) sulfuric acid, and 1-, 3-, and 4-min residence times. The dilute acid prehydrolysis
solubilized more than 90% of the hemicellulose, and increased the enzymatic digestibility of the cellulose that remained in
the solids. Compositional analysis of the pretreated solids and liquors and mass balance data show that the two pretreatment
devices had similar pretreatment performance. 相似文献
6.
Daniel Schell 《Applied biochemistry and biotechnology》1988,17(1-3):73-87
The feeding of solids into a high pressure reactor has always been difficult because of both high equipment costs and poor
material characteristics. As part of the Solar Energy Research Institute’s investigation into the acid hydrolysis process,
a lockhopper system was developed to feed wood into a vessel operating at 160°C (320°F) and 1.12 MPa (150 psig). Preliminary
results show that the lockhopper operates successfully at temperature and pressure for a limited amount of time on wood sawdust.
However, a problem that must be watched during operation is plugging of pneumatic lines by wood dust. 相似文献
7.
Cellulose hydrolysis under extremely low sulfuric acid and high-temperature conditions 总被引:12,自引:0,他引:12
Kim Jun Seok Lee Y. Y. Torget Robert W. 《Applied biochemistry and biotechnology》2001,91(1-9):331-340
The kinetics of cellulose hydrolysis under extremely low acid (ELA) conditions (0.07 wt%) and at temperatures >200°C was investigated
using batch reactors and bed-shrinking flow-through (BSFT) reactors. The maximum yield of glucose obtained from batch reactor
experiments was about 60% for α-cellulose, which occurred at 205 and 220°C. The maximum glucose yields from yellow poplar
feedstockswere substantially lower, falling in the range of 26–50%. With yellow poplar feedstocks, a large amount of glucose
was unaccounted for at the latter phase of the batch reactions. It appears that a substantial amount of released glucose condenses
with nonglucosidic substances. in liquid. The rate of glucan hydrolysis under ELA was relatively insensitive to temperature
in batch experiments for all three substrates. This contradicts the traditional concept of cellulose hydrolysis and implies
that additional factors influence the hydrolysis of glucan under ELA. Inexperiments using BSFT reactors, the glucose yields
of 87.5, 90,3, and 90.8% were obtained for yellow poplar feedstocks at 205, 220, and 235°C, respectively. The hydrolysis rate
for glucan was about three times higher with the BSFT than with the batch reactors. The difference of observed kinetics and
performance data between the BSFT and the batch reactors was far above that predicted by the reactor theory. 相似文献
8.
Ethanol production from pretreated olive tree wood and sunflower stalks by an SSF process 总被引:2,自引:0,他引:2
Encarnación Ruiz Cristóbal Cara Mercedes Ballesteros Paloma Manzanares Ignacio Ballesteros Eulogio Castro 《Applied biochemistry and biotechnology》2006,130(1-3):631-643
Olive tree wood and sunflower stalks are agricultural residues largely available at low cost in Mediterranean countries. As
renewable lignocellulosic materials, their bioconversion may allow both obtaining a value-added product, for fuel ethanol,
and facilitating their elimination. In this work, the ethanol production from olive tree wood and sunflower stalks by a simultaneous
saccharification and fermentation (SSF) process is studied. As a pretreatment, steam explosion at different temperatures was
applied. The water insoluble fractions of steam-pretreated sunflower stalks and steamed, delignified olive tree wood were
used as substrates at 10% w/v concentration for an SSF process by a cellulolytic commercial complex and Saccharomyces cerevisiae. After 72-h fermentation, ethanol concentrations up to 30 g/L were obtained in delignified steam-pretreated olive tree wood
at 230°C and 5 min. Sunflower stalks pretretated at 220°C and 5 min gave maximum ethanol concentrations of 21 g/L in SSF experiments. 相似文献
9.
Renata Bura Rodney J. Bothast Shawn D. Mansfield John N. Saddler 《Applied biochemistry and biotechnology》2003,106(1-3):319-335
A batch reactor was employed to steam explode corn fiber at various degrees of severity to evaluate the potential of using
this feedstock as part of an enzymatically mediated cellulose-to-ethanol process. Severity was controlled by altering temperature
(150–230°C), residence time (1–9 min), and SO2 concentration (0–6% [w/w] dry matter). The effects of varying the different parameters were assessed by response surface
modeling. The results indicated that maximum sugar yields (hemicellulose-derived water soluble, and cellulose-derived following
enzymatic hydrolysis) were recovered from corn fiber pretreated at 190°C for 5 minutes after exposure to 3% SO2. Sequential SO2-catalyzed steam explosion and enzymatic hydrolysis resulted in a conversion efficiency of 81% of the combined original hemicellulose
and cellulose in the corn fiber to monomeric sugars. An additional posthydrolysis step performed on water soluble hemicellulose
stream increased the concentration of sugars available for fermentation by 10%, resulting in the high conversion efficiency
of 91%. Saccharomyces cerevisiae was able to ferment the resultant corn fiber hydrolysates, perhydrolysate, and liquid fraction from the posthydrolysis steps
to 89, 94, and 85% of theoretical ethanol conversion, respectively. It was apparent that all of the parameters investigated
during the steam explosion pretreatment had a significant effect on sugar recovery, inhibitory formation, enzymatic conversion
efficiency, and fermentation capacity of the yeast. 相似文献
10.
van Walsum G. Peter Allen Stephen G. Spencer Mark J. Laser Mark S. Antal Michael J. Lynd Lee R. 《Applied biochemistry and biotechnology》1996,(1):157-170
Lignocellulosic materials pretreated using liquid hot water (LHW) (220°C, 5 MPa, 120 s) were fermented to ethanol by batch
simultaneous saccharification and fermentation (SSF) usingSaccharomyces cerevisiae in the presence ofTrichoderma reesei cellulase. SSF of sugarcane bagasse (as received), aspen chips (smallest dimension 3 mm), and mixed hardwood flour (−60 +70
mesh) resulted in 90% conversion to ethanol in 2–5 d at enzyme loadings of 15–30 FPU/g. In most cases, 90% of the final conversion
was achieved within 75 h of inoculation. Comminution of the pretreated substrates did not affect the conversion to ethanol.
The hydrolysate produced from the LHW pretreatment showed slight inhibition of batch growth ofS. cerevisiae. Solids pretreated at a concentration of 100 g/L were as reactive as those pretreated at a lower concentration, provided
that the temperature was maintained at 220°C. 相似文献
11.
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
12.
Bura Renata Mansfield Shawn D. Saddler John N. Bothast Rodney J. 《Applied biochemistry and biotechnology》2002,98(1-9):59-72
Corn fiber, a by-product of the corn wet-milling industry, represents a renewable resource that is readily available in significant
quantities and could potentially serve as a low-cost feedstock for the production of fuel-grade alcohol. In this study, we
used a batch reactor to steam explode corn fiber at various degrees of severity to evaluate the potential of using this feedstock
in the bioconversion process. The results indicated that maximum sugar yields (soluble and following enzymatic hydrolysis)
were recovered from corn fiber that was pretreated at 190°C for 5 min with 6% SO2. Sequential SO2-catalyzed steam explosion and enzymatic hydrolysis resulted in very high conversion (81%) of all polysaccharides in the corn
fiber to monomeric sugars. Subsequently, Saccharomyces cerevisiae was able to convert the resultant corn fiber hydrolysates to ethanol very efficiently, yielding 90–96% of theoretical conversion
during the fermentation process. 相似文献
13.
《Journal of Analytical and Applied Pyrolysis》1987,12(1):61-70
Chars were prepared from holm-oak wood (Quercus ilex) using sawdust, cubes (20 × 20 × 20 mm) and octagonal prisms (20 × 20 × 80 mm) by heating in nitrogen under dynamic (sawdust and cubes) and isothermal (sawdust and prisms) conditions to different final temperatures. The yield of char production depends on the wood particle size, heating rate and final temperature. The density of the chars as measured by helium displacement, ϱHe (g/cm3), is influenced by the wood particle size and heating conditions. Chars prepared from holm-oak wood are essentially microporous solids. The apparent surface area and the micropore volume increase only slightly up to the treatment temperature of 500°C, increase greatly up to 800°C and decrease at higher temperatures. 相似文献
14.
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
15.
Daniel J. Schell Jody Farmer Millie Newman James D. McMillan 《Applied biochemistry and biotechnology》2003,105(1-3):69-85
Corn stover is a domestic feedstock that has potential to produce significant quantities of fuel ethanol and other bioenergy
and biobased products. However, comprehensive yield and carbon mass balance information and validated kinetic models for dilute-sulfuric
acid (H2SO4) pretreatment of corn stover have not been available. This has hindered the estimation of process economics and also limited
the ability to perform technoeconomic modeling to guide research. To better characterize pretreatment and assess its kinetics,
we pretreated corn stover in a continuous 1 t/d reactor. Corn stover was pretreated at 20% (w/w) solids concentration over
a range of conditions encompassing residence times of 3–12 min, temperatures of 165–195°C, and H2SO4 concentrations of 0.5–1.4% (w/w). Xylan conversion yield and carbon mass balance data were collected at each run condition.
Performance results were used to estimate kinetic model parameters assuming biphasic hemicellulose hydrolysis and a hydrolysis
mechanism incorporating formation of intermediate xylo-oligomers. In addition, some of the pretreated solids were tested in
a simultaneous saccharification and fermentation (SSF) process to measure the reactivity of their cellulose component to enzymatic
digestion by cellulase enzymes. Monomeric xylose yields of 69–71% and total xylose yields (monomers and oligomers) of 70–77%
were achieved with performance level depending on pretreatment severity. Cellulose conversion yields in SSF of 80–87% were
obtained for some of the most digestible pretreated solids. 相似文献
16.
Ethanol production from steam-explosion pretreated wheat straw 总被引:1,自引:0,他引:1
Ignacio Ballesteros Ma José Negro José Miguel Oliva Araceli Cabañas Paloma Manzanares Mercedes Ballesteros 《Applied biochemistry and biotechnology》2006,130(1-3):496-508
Bioconversion of cereal straw to bioethanol is becoming an attractive alternative to conventional fuel ethanol production
from grains. In this work, the best operational conditions for steam-explosion pretreatment of wheat straw for ethanol production
by a simultaneous saccharification and fermentation process were studied, using diluted acid [H2SO4 0.9% (w/w)] and water as preimpregnation agents. Acid-or water-impregnated biomass was steam-exploded at different temperatures
(160–200°C) and residence times (5, 10, and 20 min). Composition of solid and filtrate obtained after pretreatment, enzymatic
digestibility and ethanol production of pretreated wheat straw at different experimental conditions was analyzed. The best
pretreatment conditions to obtain high conversion yield to ethanol (approx 80% of theoretical) of cellulose-rich residue after
steam-explosion were 190°C and 10 min or 200°C and 5 min, in acid-impregnated straw. However, 180°C for 10 min in acid-impregnated
biomass provided the highest ethanol yield referred to raw material (140 L/t wheat straw), and sugars recovery yield in the
filtrate (300 g/kg wheat straw). 相似文献
17.
Karin Öhgren Mats Galbe Guido Zacchi 《Applied biochemistry and biotechnology》2005,124(1-3):1055-1067
In this study, corn stover with a dry matter content of 20% was impregnated with SO2 and then steam pretreated for various times at various temperatures. The pretreatment was evaluated by enzymatic hydrolysis
of the solid material and analysis of the sugar content in the liquid. The maximum overall yield of glucose, 89% of the theoretical
based on the glucan in the raw material, was achieved when the corn stover was pretreated at 200°C for 10 min. The maximum
overall yield of xylose, 78%, was obtained with pretreatment at 190°C for 5 min. 相似文献
18.
Sugar cane bagasse consists of hemicellulose (24%) and cellulose (38%), and bioconversion of both fractions to ethanol should
be considered for a viable process. We have evaluated the hydrolysis of pretreated bagasse with combinations of cellulase,
β-glucosidase, and hemicellulase. Ground bagasse was pretreated either by the AFEX process (2NH3: 1 biomass, 100 °C, 30 min) or with NH4OH (0.5 g NH4OH of a 28% [v/v] per gram dry biomass; 160 °C, 60 min), and composition analysis showed that the glucan and xylan fractions remained largely
intact. The enzyme activities of four commercial xylanase preparations and supernatants of four laboratory-grown fungi were
determined and evaluated for their ability to boost xylan hydrolysis when added to cellulase and β-glucosidase (10 filter
paper units [FPU]: 20 cellobiase units [CBU]/g glucan). At 1% glucan loading, the commercial enzyme preparations (added at
10% or 50% levels of total protein in the enzyme preparations) boosted xylan and glucan hydrolysis in both pretreated bagasse
samples. Xylanase addition at 10% protein level also improved hydrolysis of xylan and glucan fractions up to 10% glucan loading
(28% solids loading). Significant xylanase activity in enzyme cocktails appears to be required for improving hydrolysis of
both glucan and xylan fractions of ammonia pretreated sugar cane bagasse. 相似文献
19.
An ultraviolet (UV) coil reactor was designed and used for the online sterilization of cheese whey. Its microbial destruction
efficiency was compared to that of the conventionally used UV reactor. Both reactors have the same geometry (840 ml volume
and 17 mm gap size) and were tested at 11 flow rates of 5, 10, 15, 20, 25, 30, 35, 40, 50, 60, and 70 ml/min. The results
obtained from this study showed that despite of its high turbidity, cheese whey could be sterilized using UV radiation if
the proper reactor design and flow rate are used. The performances of the UV reactors were governed by the flow rate and the
hydraulics of flow inside the reactor. The flow was laminar in both the reactors, as the Reynolds number was in the range
of 1.39–20.10. The phenomenon of Dean Flow was observed in the coil reactor and the Dean number was in the range of 1.09–15.41.
Dean vortices resulted in higher microbial destruction efficiency in the coil reactor in a shorter retention time. The rate
of microbial destruction was found to be exponential in the conventional reactor and polynomial in the coil reactor. Increasing
the flow rate from 5 ml/min to 70 ml/min decreased the microbial destruction efficiency of the conventional reactor from 99.40
to 31.58%, while the microbial destruction efficiency in the coil reactor increased from 60.77% at the flow rate of 5 ml/min
to 99.98% at the flow rate of 30 ml/min and then decreased with further increases in flow rate reaching 46.2% at the flow
rate of 70 ml/min. The maximum effluent temperatures in the conventional and coil reactors were 45.8 and 46.1°C, respectively.
Fouling in the coil reactor was significantly less compared to the conventional reactor. The extent of fouling was influenced
by flow rate and reactor’s hydraulics. 相似文献
20.
Production of phenol compounds by alkaline treatment of technical hydrolysis lignin and wood biomass
Aqueous alkaline depolymerization of technical hydrolysis lignin (THL) was carried out with a 5% NaOH solution at a temperature
of 180°C for 6 hours, the ratio between the biomass and depolymerizing agent being 1:8. The poplar wood sawdust was treated
under the same conditions for 2 hours, where anthraquinone was added as a catalyst (0.5 wt %). The poplar wood bark was treated
for 4 hours, without anthraquinone. Compounds contained in the aqueous phase were extracted three times by means of toluene
for a ratio between the organic and aqueous phases equal to 1:5, 1:5 and 1:5. The compounds 2-methoxyphenol, 2,6-dimethoxyphenol,
4-hydroxy-3-methoxybenzaldehyde, 1-(4-hydroxy-3-methoxyphenyl)ethanone, 4-hydroxy-3,5-dimethoxybenzaldehyde, etc., were identified
through GC-MS analysis in obtained extracts.
Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 144–146, March–April, 2008. 相似文献