共查询到10条相似文献,搜索用时 122 毫秒
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.
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
8.
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
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