共查询到20条相似文献,搜索用时 734 毫秒
1.
Deepti A. Salvi Giovanna M. Aita Diana Robert Victor Bazan 《Applied biochemistry and biotechnology》2010,161(1-8):67-74
A new pretreatment technology using dilute ammonium hydroxide was evaluated for ethanol production on sorghum. Sorghum fibers, ammonia, and water at a ratio of 1:0.14:8 were heated to 160 °C and held for 1 h under 140–160 psi pressure. Approximately, 44% lignin and 35% hemicellulose were removed during the process. Hydrolysis of untreated and dilute ammonia pretreated fibers was carried out at 10% dry solids at an enzyme concentration of 60 FPU Spezyme CP and 64 CBU Novozyme 188/g glucan. Cellulose digestibility was higher (84%) for ammonia pretreated sorghum as compared to untreated sorghum (38%). Fermentations with Saccharomyces cerevisiae D5A resulted in 24 g ethanol /100 g dry biomass for dilute ammonia pretreated sorghum and 9 g ethanol /100 g dry biomass for untreated sorghum. 相似文献
2.
Farzaneh Teymouri Hasan Alizadeh Lizbeth Laureano-Pérez Bruce Dale Mariam Sticklen 《Applied biochemistry and biotechnology》2004,116(1-3):1183-1191
A critical parameter affecting the economic feasibility of lignocellulosic bioconversion is the production of inexpensive
and highly active cellulase enzymes in bulk quantity. A promising approach to reduce enzyme costs is to genetically transform
plants with the genes of these enzymes, thereby producing the desired cellulases in the plants themselves. Extraction and
recovery of active proteins or release of active cellulase from the plants during bioconversion could have a significant positive
impact on overall lignocellulose conversion economics. The effects of ammonia fiber explosion (AFEX) pretreatment variables
(treatment temperature, moisture content, and ammonia loading) on the activity of plant-produced heterologous cellulase enzyme
were individually investigated via heat treatmett or ammonia treatment. Finally, we studied the effects of all these variables
in concert through the AFEX process. The plant materials included transgenic tobacco plants expressing E1 (endoglucanase from
Acidothermus cellulolyticus). The E1 activity was measured in untreated and AFEX-treated tobacco leaves to investigate the effects of the treatment on
the activity of this enzyme. The maximum observed activity retention in AFEX-treated transgenic tobacco samples compared with
untreated samples was approx 35% (at 60°C, 0.5∶1 ammonia loading, and 40% moisture). Based on these findings, it is our opinion
that AFEX pretreatment is not a suitable option for releasing cellulase enzyme from transgenic plants. 相似文献
3.
De La Rosa Luis B. Reshamwala Sultan Latimer Vivian M. Shawky Bahaa T. Dale Bruce E. Stuart Earnest D. 《Applied biochemistry and biotechnology》1994,(1):483-497
The herbaceous crops that may provide fermentable carbohydrates for production of fuels and chemicals also contain 10–20%
protein. Protein coproduction with biomass-derived fuels and chemicals has important advantages: (1) food and fuel production
can be integrated, and (2) protein is a high-value product that may significantly improve overall process economics. We report
the results of an integrated approach to producing protein and fermentable sugars from one herbaceous species, Coastal Bermudagrass
(CBG). The ammonia fiber explosion (AFEX) process makes possible over 90% conversion of cellulose and hemicellulose to simple
sugars (about 650 mg reducing sugars/g dry CBG) at 5 IU cellulase/g vs < 20% conversion for untreated CBG. The AFEX treatment
also improves protein extraction from CBG; over 80% protein recovery is possible from AFEX-treated CBG vs about 30% recovery
from untreated CBG. 相似文献
4.
Ammonia fiber explosion treatment of corn stover 总被引:1,自引:0,他引:1
Farzaneh Teymouri Lizbeth Laureano-Pérez Hasan Alizadeh Bruce E. Dale 《Applied biochemistry and biotechnology》2004,115(1-3):951-963
Optimizing process conditions and parameters such as ammonia loading, moisture content of biomass, temperature, and residence
time is necessary for maximum effectiveness of the ammonia fiber explosion process. Approximate optimal pretreatment conditions
for corn stover were found to be temperature of 90°C, ammonia: dry corn stover mass ratio of 1∶1, moisture content of corn
stover of 60% (dry weight basis), and residence time (holding at target temperature), of 5 min. Approximately 98% of the theoretical
glucose yield was obtained during enzymatic hydrolysis of the optimal treated corn stover using 60 filter paper units (FPU)
of cellulase enzyme/g of glucan (equal to 22 FPU/g of dry corn stover). The ethanol yield from this sample was increased up
to 2.2 times over that of untreated sample. Lowering enzyme loading to 15 and 7.5 FPU/g of glucan did not significantly affect
the glucose yield compared with 60 FPU, and any differences between effects at different enzyme levels decreased as the treatment
temperature increased. 相似文献
5.
Bradshaw TC Alizadeh H Teymouri F Balan V Dale BE 《Applied biochemistry and biotechnology》2007,137(1-12):395-405
Plant materials from the vegetative growth stage of reed canarygrass and the seed stage of reed canarygrass are pretreated by ammonia fiber expansion (AFEX) and enzymatically hydrolyzed using 15 filter paper units (FPU) cellulase/g glucan to evaluate glucose and xylose yields. Percent conversions of glucose and xylose, effects of temperature and ammonia loading, and hydrolysis profiles are analyzed to determine the most effective AFEX treatment condition for each of the selected materials. The controls used in this study were untreated samples of each biomass material. All pretreatment conditions tested enhanced enzyme digestibility and improved sugar conversions for reed canarygrass compared with their untreated counterparts. Based on 168 h hydrolysis results using 15 FPU Spezyme CP cellulase/g glucan the most effective AFEX treatment conditions were determined as: vegetative growth stage of reed canarygrass--100 degrees C, 60% moisture content, 1.2:1 kg ammonia/kg of dry matter (86% glucose and 78% xylose) and seed stage of reed canarygrass--100 degrees C, 60% moisture content, 0.8:1 kg ammonia/kg of dry matter (89% glucose and 81% xylose). Supplementation by commercial Multifect 720 xylanase along with cellulase further increased both glucose and xylose yields by 10-12% at the most effective AFEX conditions. 相似文献
6.
Isci A Himmelsbach JN Pometto AL Raman DR Anex RP 《Applied biochemistry and biotechnology》2008,144(1):69-77
Simultaneous saccharification and fermentation (SSF) of switchgrass was performed following aqueous ammonia pretreatment.
Switchgrass was soaked in aqueous ammonium hydroxide (30%) with different liquid–solid ratios (5 and 10 ml/g) for either 5
or 10 days. The pretreatment was carried out at atmospheric conditions without agitation. A 40–50% delignification (Klason
lignin basis) was achieved, whereas cellulose content remained unchanged and hemicellulose content decreased by approximately
50%. The Sacccharomyces cerevisiae (D5A)-mediated SSF of ammonia-treated switchgrass was investigated at two glucan loadings (3 and 6%) and three enzyme loadings
(26, 38.5, and 77 FPU/g cellulose), using Spezyme CP. The percentage of maximum theoretical ethanol yield achieved was 72.
Liquid–solid ratio and steeping time affected lignin removal slightly, but did not cause a significant change in overall ethanol
conversion yields at sufficiently high enzyme loadings. These results suggest that ammonia steeping may be an effective method
of pretreatment for lignocellulosic feedstocks. 相似文献
7.
Ming J. Lau Ming W. Lau Christa Gunawan Bruce E. Dale 《Applied biochemistry and biotechnology》2010,162(7):1847-1857
Empty palm fruit bunch fiber (EPFBF), a readily available cellulosic biomass from palm processing facilities, is investigated
as a potential carbohydrate source for cellulosic ethanol production. This feedstock was pretreated using ammonia fiber expansion
(AFEX) and enzymatically hydrolyzed. The best tested AFEX conditions were at 135 °C, 45 min retention time, water to dry biomass
loading of 1:1 (weight ratio), and ammonia to dry biomass loading of 1:1 (weight ratio). The particle size of the pretreated
biomass was reduced post-AFEX. The optimized enzyme formulation consists of Accellerase (84 μL/g biomass), Multifect Xylanase
(31 μL/g biomass), and Multifect Pectinase (24 μL/g biomass). This mixture achieved close to 90% of the total maximum yield
within 72 h of enzymatic hydrolysis. Fermentation on the water extract of this biomass affirms that nutrients solely from
the pretreated EPFBF can support yeast growth for complete glucose fermentation. These results suggest that AFEX-treated EPFBF
can be used for cellulosic biofuels production because biomass recalcitrance has been overcome without reducing the fermentability
of the pretreated materials. 相似文献
8.
Switchgrass (Panicum vergatum) is a potential feedstock for future cellulosic biorefineries. Such a feedstock may also provide protein, most likely for
use as an animal feed. In this paper, we present a potential scheme for integrating fiber processing with extractions to obtain
both sugar and protein products from switchgrass pretreated using Ammonia Fiber Expansion (AFEX). Solutions of 3% aqueous
ammonia at pH 10.5 provided optimal extraction of proteins. Addition of the nonionic surfactant Tween-80 improved protein
recovery for AFEX-treated materials. It was determined that an extraction following AFEX solubilized approximately 40% of
the protein, while a subsequent hydrolysis solubilized much of the remaining protein while producing 325 g sugar per kg biomass.
The remaining insoluble residue contained very little protein or ash, making it ideal for heat and power production. In contrast,
an extraction following hydrolysis solubilized only 68% of the original protein in the biomass, while obtaining slightly higher
sugar yields. 相似文献
9.
Bagasse, corn husk, and switchgrass were pretreated with ammonia water to enhance enzymatic hydrolysis. The sample (2 g) was
mixed with 1–6 mL ammonia water (25–28% ammonia) and autoclaved at 120°C for 20 min. After treatment, the product was vacuum-dried
to remove ammonia gas. The dried solid could be used immediately in the enzymatic hydrolysis without washing. The enzymatic
hydrolysis was effectively improved with more than 0.5 and 1 mL ammonia water/g for corn husk and bagasse, respectively. In
bagasse, glucose, xylose, and xylobiose were the main products. The adsorption of CMCase and xylanase was related to the initial
rate of enzymatic hydrolysis. In corn husks, arabinoxylan extracted by pretreatment was substantially unhydrolyzed because
of the high ratio of arabinose to xylose (0.6). The carbohydrate yields from cellulose and hemicellulose were 72.9% and 82.4%
in bagasse, and 86.2% and 91.9% in corn husk, respectively. The ammonia/water pretreatment also benefited from switchgrass
(Miscanthus sinensis and Solidago altissima L.) hydrolysis. 相似文献
10.
Switchgrass was used as a model feedstock to determine the influence of pretreatment conditions and biomass quality on enzymatic hydrolysis using different enzyme products. Dilute sulfuric acid and soaking in aqueous ammonia pretreatments were used to produce biomass with varied levels of hemicellulose and lignin sheathing. Pretreated switchgrass solids were tested with simple enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF) with three commercial enzyme products: Accellerase 1000 (Genencor), Spezyme CP (Genencor)/Novozyme 188 (Novozymes), and Celluclast/Novozyme 188 (Novozymes). Enzymes were loaded on a common activity basis (FPU/g cellulose and CBU/g cellulose). Despite identical enzyme loadings, glucose yields were significantly different for both acid and alkaline pretreatments but differences diminished as hydrolysis progressed for acid-pretreated biomass. Cellobiose concentrations in Accellerase treatments indicated an initial β-glucosidase limitation that became less significant over time. SSF experiments showed that differences in glucose and ethanol yields could not be attributed to enzyme product inhibition. Yield discrepancies of glucose or ethanol in acid pretreatment, alkaline pretreatment, and acid pretreatment/SSF were as much as 15%, 19%, and 5%. These results indicate that standardized protocols for measuring enzyme activity may not be adequate for assessing activity using pretreated biomass substrates. 相似文献
11.
Protein Extraction and Enzymatic Hydrolysis of Ammonia-Treated Cassava Leaves (Manihot esculenta Crantz) 总被引:2,自引:0,他引:2
Lauris Urribarrí David Chacón Orlaidy González Alexis Ferrer 《Applied biochemistry and biotechnology》2009,153(1-3):94-102
In the present work, cassava leaves were treated with 0.5 kg ammonia/kg dry matter at 78 °C and 30% moisture content in a 2-kg reactor. Protein extraction was carried out with a calcium hydroxide solution (pH 10) for 30 min at several temperatures (30 °C, 45 °C, 60 °C, 75 °C, and 90 °C) and solid/liquid ratios (1:10 and 1:15) in a thermostatized bath. Soluble protein content of the extracts was determined by Lowry’s method. Dry substrate concentrations of 5%, 7.5%, and 10% and enzyme doses of 2 and 5 IU/g dry matter were used for the enzymatic hydrolysis in an orbital incubator at 50 °C and 100 rpm. Both cellulase and xylanase were used. Reducing sugars produced were determined with the dinitrosalicylic acid method. The highest protein extraction yield for the ammonia-treated leaves was 29.10%, which was 50% higher than with the untreated leaves (20%), and was obtained at 90 °C with a 1:10 solid/liquid ratio. The concentrate had a protein content of 36.35% and the amino acid profile was suitable for swine and poultry. The highest sugar yield was 54.72% with respect to theoretical and was obtained with 5% solids and an enzyme dose of 5 IU/g dry matter. This yield was 3.4 times higher than the yield of the untreated leaves (16.13%). These results indicate that cassava leaves have a great potential for animal feeding and ethanol production. Both protein extraction and sugar yields may be enhanced by optimizing the ammonia treatment. 相似文献
12.
In this study, sugarcane bagasse was pretreated with ammonium hydroxide, and the effectiveness of the pretreatment on enzyme hydrolysis and ethanol production was examined. Bagasse was soaked in ammonium hydroxide and water at a ratio of 1:0.5:8 for 0–4 days at 70 °C. Approximately, 14–45 % lignin, 2–6 % cellulose, and 13–22 % hemicellulose were removed during a 0.5- to 4-day ammonia soaking period. The highest glucan conversion of sugarcane bagasse soaked in dilute ammonia at moderate temperature by cellulase was accomplished at 78 % with 75 % of the theoretical ethanol yield. Under the same conditions, untreated bagasse resulted in a cellulose digestibility of 29 and 27 % of the theoretical ethanol yield. The increased enzymatic digestibility and ethanol yields after dilute ammonia pretreatment was related to a combined effect of the removal of lignin and increase in the surface area of fibers. 相似文献
13.
Zongping Sun Xiaoyan Ge Donglin Xin Junhua Zhang 《Applied biochemistry and biotechnology》2014,172(3):1506-1516
The effect of aqueous ammonia pretreatment on the hydrolysis of different corn stover fractions (rind, husk, leaf, and pith) by xylanase (XYL) with cellulases (CELs) was evaluated. The aqueous ammonia pretreatment had excellent delignification ability (above 66 %) for different corn stover fractions. The corn rind exhibited the lowest susceptibility to aqueous ammonia pretreatment. The pretreated rind showed the lowest hydrolyzability by CEL and XYL, which was supported by a high content of crystalline cellulose in the hydrolyzed residues of rind, as confirmed by X-ray diffraction (XRD). With the addition of 1 mg XYL/g dry matter, a high glucose yield (above 90 %) could be obtained from the pretreated rind by CEL. The results revealed that a high hydrolyzate yield of corn rind after aqueous ammonia pretreatment could be obtained with 1 mg xylanase/g dry matter, showing that aqueous ammonia pretreatment and xylanase addition to cellulases have great potential for the efficient hydrolysis of corn stover without previous fractionation. 相似文献
14.
Optimization of steam pretreatment of corn stover to enhance enzymatic digestibility 总被引:5,自引:0,他引:5
Among the available agricultural byproducts, corn stover, with its yearly production of 10 million t (dry basis), is the most
abundant promising raw material for fuel ethanol production in Hungary. In the United States, more than 216 million to fcorn
stover is produced annually, of which a portion also could possibly be collected for conversion to ethanol. However, a network
of lignin and hemicellulose protects cellulose, which is the major source of fermentable sugars in corn stover (approx 40%
of the dry matter [DM]). Steam pretreatment removes the major part of the hemicellulose from the solid material and makes
the cellulose more susceptible to enzymatic digestion. We studied 12 different combinations of reaction temperature, time,
and pH during steam pretreatment. The best conditions (200°C, 5 min, 2% H2SO4) increased the enzymatic conversion (from cellulose to glucose) of corn stover more then four times, compared to untreated
material. However, steam pretreatment at 190°C for 5 min with 2% sulfuric acid resulted in the highest overall yield of sugars,
56.1 g from 100 g of untreated material (DM), corresponding to 73% of the theoretical. The liquor following steam explosion
was fermented using Saccharomyces cerevisiae to investigate the inhibitory effect of the pretreatment. The achieved ethanol yield was slightly higher than that obtained
with a reference sugar solution. This demonstrates that baker's yeast could adapt to the pretreated liquor and ferment the
glucose to ethanol efficiently. 相似文献
15.
Binod Rijal Gwen Biersbach William R. Gibbons Scott W. Pryor 《Applied biochemistry and biotechnology》2014,174(2):845-854
Switchgrass (SG), corn stover (CS), and prairie cordgrass (PCG) pretreated with ammonia fiber expansion (AFEX) were densified using a novel low-temperature, low-pressure densification method. Simultaneous saccharification and fermentation (SSF) and separate hydrolysis and fermentation (SHF) were performed with loose and densified AFEX-treated biomass to determine the effect of post-AFEX densification. Biomass particle size reduction before pretreatment increased 144-h SSF ethanol yields from densified material by 8–9 % although no significant differences were seen in the first 72 h. Grinding material after densification had no impact on final ethanol yields but increased production rates in the first 24–48 h. Low-pressure, post-AFEX densification had no adverse effects on SSF ethanol yields from SG or CS but reduced yields from densified PCG by 16 %. Glucose concentrations after hydrolysis (SHF) showed similar trends. Ethanol yields after SHF, however, showed that densification had no significant impact on CS or PCG but reduced final ethanol yields from SG. 相似文献
16.
Vijay Sundaram Kasiviswanathan Muthukumarappan Stephen Gent 《Applied biochemistry and biotechnology》2017,181(3):1060-1079
Lignocellulosic feedstocks corn stover, prairie cord grass, and switchgrass were subjected to ammonia fiber expansion (AFEX?) pretreatment and densified using extrusion pelleting and ComPAKco densification technique. The effects of AFEX? pretreatment and densification were studied on the fast pyrolysis product yields. Feedstocks were milled in a hammer mill using three different screen sizes (2, 4, and 8 mm) and were subjected to AFEX? pretreatment. The untreated and AFEX?-pretreated feedstocks were moisture adjusted at three levels (5, 10, and 15 % wb) and were extruded using a lab-scale single screw extruder. The barrel temperature of the extruder was maintained at 75, 100, and 125 °C. Durability of the extruded pellets made from AFEX?-pretreated corn stover, prairie cord grass, and switchgrass varied from 94.5 to 99.2, 94.3 to 98.7, and 90.1 to 97.5 %, respectively. Results of the thermogravimetric analysis showed the decrease in the decomposition temperature of the all the feedstocks after AFEX? pretreatment indicating the increase in thermal stability. Loose and densified feedstocks were subjected to fast pyrolysis in a lab-scale reactor, and the yields (bio-oil and bio-char) were measured. Bio-char obtained from the AFEX?-pretreated feedstocks exhibited increased bulk and particle density compared to the untreated feedstocks. The properties of the bio-oil were statistically similar for the untreated, AFEX?-pretreated, and AFEX?-pretreated densified feedstocks. Based on the bio-char and bio-oil yields, the AFEX?-pretreated feedstocks and the densified AFEX?-pretreated feedstocks (pellets and PAKs) exhibited similar behavior. Hence, it can be concluded that densifying the AFEX?-pretreated feedstocks could be a viable option in the biomass-processing depots to reduce the transportation costs and the logistical impediments without affecting the product yields. 相似文献
17.
Pretreatment and Fractionation of Corn Stover by Soaking In Ethanol and Aqueous Ammonia 总被引:1,自引:0,他引:1
Tae Hyun Kim Nhuan P. Nghiem Kevin B. Hicks 《Applied biochemistry and biotechnology》2009,153(1-3):171-179
A new process for pretreatment of lignocellulosic biomass, designated the soaking in ethanol and aqueous ammonia (SEAA) process, was developed to improve hemicellulose preservation in solid form. In the SEAA process, an aqueous ammonia solution containing ethanol is used. Corn stover was treated with 15 wt.% ammonia at 1:9 solid–liquid ratio (by weight) at 60 °C for 24 h with ethanol added at 1, 5, 20, and 49 wt.% (balance was water). The extents by which xylan was solubilized with no ethanol and with ethanol added at 1, 5, 20, and 49 wt.% of the total liquid were 17.2%, 16.7%, 14.5%, 10.4%, and 6.3% of the original xylan, respectively. Thus, at the highest ethanol concentration used the loss of hemicellulose to the liquid phase was reduced by 63%. The digestibility of glucan and xylan in the pretreated corn stover samples by cellulase was not affected by ethanol addition of up to 20 wt.%. The enzymatic digestibility of the corn stover treated with 49 wt.% ethanol added was lower than the digestibility of the sample treated with no ethanol addition. Thus, based on these results, 20 wt.% was found to be the optimum ethanol concentration for use in the SEAA process for pretreatment of corn stover. 相似文献
18.
Wang Lin Dale Bruce E. Yurttas Lale Goldwasser I. 《Applied biochemistry and biotechnology》1998,(1):51-66
Process designs were conducted for each unit of the conceptual ammonia fiber explosion (AFEX) process, and fixed capital investment
and operating costs were estimated. AFEX costs about $20-40/t of dry bio-mass treated. Several promising areas for reducing
process costs exist. Return on investment (ROI) calculations were also done for AFEX-treated materials (as digestibility-enhanced
animal feeds), in conjunction with sensitivity analyses on the overall processing costs. Estimated ROIs range from over 100%/y
to negative, depending on the system variables. The most important variables are the cost of corn and corn fiber, ammonia
loading, and whether or not drying is required. 相似文献
19.
Hui Wang Radhakrishnan Srinivasan Fei Yu Philip Steele Qi Li Brian Mitchell Aditya Samala 《Applied biochemistry and biotechnology》2012,167(2):285-297
Bio-oil produced from biomass by fast pyrolysis has the potential to be a valuable substitute for fossil fuels. In a recent work on pinewood, we found that pretreatment alters the structure and chemical composition of biomass, which influence fast pyrolysis. In this study, we evaluated dilute acid, steam explosion, and size reduction pretreatments on sweetgum, switchgrass, and corn stover feedstocks. Bio-oils were produced from untreated and pretreated feedstocks in an auger reactor at 450?°C. The bio-oil??s physical properties of pH, water content, acid value, density, and viscosity were measured. The chemical characteristics of the bio-oils were determined by gas chromatography?Cmass spectrometry. The results showed that bio-oil yield and composition were influenced by the pretreatment method and feedstock type. Bio-oil yields of 52, 33, and 35?wt% were obtained from medium-sized (0.68?C1.532?mm) untreated sweetgum, switchgrass, and corn stover, respectively, which were higher than the yields from other sizes. Bio-oil yields of 56, 46, and 51?wt% were obtained from 1?% H2SO4-treated medium-sized sweetgum, switchgrass, and corn stover, respectively, which were higher than the yields from untreated and steam explosion treatments. 相似文献
20.
M. Moniruzzaman B. E. Dale R. B. Hespell R. J. Bothast 《Applied biochemistry and biotechnology》1997,67(1-2):113-126
Corn fiber is a grain-processing residue containing significant amounts of cellulose, hemicellulose, and starch, which is collected in facilities where fuel ethanol is currently manufactured. Preliminary research has shown that corn fiber (30% moisture dry weight basis [dwb]) responds well to ammonia-fiber explosion (AFEX) pretreatment. However, an important AFEX pretreatment variable that has not been adequately explored for corn fiber is sample moisture. In the present investigation, we determined the best AFEX operating conditions for pretreatment of corn fiber at high moisture content (150% moisture dwb). The optimized AFEX treatment conditions are defined in terms of the moisture content, particle size, ammonia to biomass ratio, temperature, and residence time using the response of the pretreated biomass to enzymatic hydrolysis as an indicator. Approximate optimal-pretreatment conditions for unground corn fiber containing 150% (dwb) moisture were found to be: temperature, 90?C; ammonia: dry corn fiber mass ratio, 1:1; and residence time 30 min (average reactor pressure under these conditions was 200 pounds per square inch [psig]). Enzymatic hydrolysis of the treated corn fiber was performed with three different enzyme combinations. More than 80% of the theoretical sugar yield was obtained during enzymatic hydrolysis using the best enzyme combination after pretreatment of corn fiber under the optimized conditions previously described. A simple process for enzyme recovery and reuse to hydrolyze multiple portions of AFEX-treated corn fiber by one portion of enzyme preparation is demonstrated. Using this process, five batches of fresh substrate (at a concentration of 5% w/v) were successfully hydrolyzed by repeated recovery and reuse of one portion of enzyme preparation, with the addition of a small portion of fresh enzyme in each subsequent recycling step. 相似文献