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1.
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
2.
Solange I. Mussatto Giuliano Dragone Marcela Fernandes Adriane M. F. Milagres Inês C. Roberto 《Cellulose (London, England)》2008,15(5):711-721
Brewer’s spent grain components (cellulose, hemicellulose and lignin) were fractionated in a two-step chemical pretreatment
process using dilute sulfuric acid and sodium hydroxide solutions. The cellulose pulp produced was hydrolyzed with a cellulolytic
complex, Celluclast 1.5 L, at 45 °C to convert the cellulose into glucose. Several conditions were examined: agitation speed
(100, 150 and 200 rpm), enzyme loading (5, 25 and 45 FPU/g substrate), and substrate concentration (2, 5 and 8% w/v), according
to a 23 full factorial design aiming to maximize the glucose yield. The obtained results were interpreted by analysis of variance
and response surface methodology. The optimal conditions for enzymatic hydrolysis of brewer’s spent grain were identified
as 100 rpm, 45 FPU/g and 2% w/v substrate. Under these conditions, a glucose yield of 93.1% and a cellulose conversion (into
glucose and cellobiose) of 99.4% was achieved. The easiness of glucose release from BSG makes this substrate a raw material
with great potential to be used in bioconversion processes. 相似文献
3.
The effect of particle size on hydrolysis reaction rates and rheological properties in cellulosic slurries 总被引:1,自引:0,他引:1
The effect of varying initial particle sizes on enzymatic hydrolysis rates and rheological properties of sawdust slurries is investigated. Slurries with four particle size ranges (33 microm < x < or = 75 microm, 150 microm < x < or = 180 microm, 295 microm < x < or = 425 microm, and 590 microm < x < or = 850 microm) were subjected to enzymatic hydrolysis using an enzyme dosage of 15 filter paper units per gram of cellulose at 50 degrees C and 250 rpm in shaker flasks. At lower initial particle sizes, higher enzymatic reaction rates and conversions of cellulose to glucose were observed. After 72 h 50 and 55% more glucose was produced from the smallest size particles than the largest size ones, for initial solids concentration of 10 and 13% (w/w), respectively. The effect of initial particle size on viscosity over a range of shear was also investigated. For equivalent initial solids concentration, smaller particle sizes result in lower viscosities such that at a concentration of 10% (w/w), the viscosity decreased from 3000 cP for 150 microm < x < or = 180 microm particle size slurries to 61.4 cP for 33 microm < x < or = 75 microm particle size slurries. Results indicate particle size reduction may provide a means for reducing the long residence time required for the enzymatic hydrolysis step in the conversion of biomass to ethanol. Furthermore, the corresponding reduction in viscosity may allow for higher solids loading and reduced reactor sizes during large-scale processing. 相似文献
4.
Rosgaard L Andric P Dam-Johansen K Pedersen S Meyer AS 《Applied biochemistry and biotechnology》2007,143(1):27-40
In this study, the applicability of a “fed-batch” strategy, that is, sequential loading of substrate or substrate plus enzymes
during enzymatic hydrolysis was evaluated for hydrolysis of steam-pretreated barley straw. The specific aims were to achieve
hydrolysis of high substrate levels, low viscosity during hydrolysis, and high glucose concentrations. An enzyme system comprising
Celluclast and Novozyme 188, a commercial cellulase product derived from Trichoderma reesei and a β-glucosidase derived from Aspergillus niger, respectively, was used for the enzymatic hydrolysis. The highest final glucose concentration, 78 g/l, after 72 h of reaction,
was obtained with an initial, full substrate loading of 15% dry matter weight/weight (w/w DM). Conversely, the glucose yields,
in grams per gram of DM, were highest at lower substrate concentrations, with the highest glucose yield being 0.53 g/g DM
for the reaction with a substrate loading of 5% w/w DM after 72 h. The reactions subjected to gradual loading of substrate
or substrate plus enzymes to increase the substrate levels from 5 to 15% w/w DM, consistently provided lower concentrations
of glucose after 72 h of reaction; however, the initial rates of conversion varied in the different reactions. Rapid cellulose
degradation was accompanied by rapid decreases in viscosity before addition of extra substrate, but when extra substrate or
substrate plus enzymes were added, the viscosities of the slurries increased and the hydrolytic efficiencies decreased temporarily. 相似文献
5.
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
6.
Soybean hulls were subjected to thermo-mechanical extrusion pretreatment at various in-barrel moisture contents and screw
speeds. Extrusion degraded the lignocellulosic structure and enhanced enzymatic hydrolysis of soybean hulls, with up to 155%
increase in glucose yield as compared to untreated substrate. Greater glucose yields were observed at higher in-barrel moistures
(45% and 50%) and lower screw speed (280 and 350 rpm). Maximum 74% cellulose to glucose conversion resulted from using a two-enzyme
cocktail consisting of cellulase and β-glucosidase. Conversion increased to 87% when a three-enzyme cocktail having a cell
wall degrading enzyme complex was used for hydrolysis. Fermentation inhibitors, such as furfural, 5-(hydroxymethyl)-2-furaldehyde
(HMF), and acetic acid, were found in the extrusion pretreated soybean hulls and hydrolysate. However, their concentrations
were below the known thresholds for inhibition. Fermentation of hydrolysate by Saccharomyces cerevisiae led to high yields of ethanol, with concentration ranging from 13.04 to 15.44 g/L. 相似文献
7.
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
8.
Enhancing the enzymatic hydrolysis of cellulosic materials using simultaneous ball milling 总被引:1,自引:0,他引:1
Mais Ursula Esteghlalian Ali R. Saddler John N. Mansfield Shawn D. 《Applied biochemistry and biotechnology》2002,98(1-9):815-832
One of the limiting factors restricting the effective and efficient bioconversion of softwood-derived lignocellulosic residues
is the recalcitrance of the substrate following pretreatment. Consequently, the ensuing enzymatic process requires relatively
high enzyme loadings to produce monomeric carbohydrates that are readily fermentable by ethanologenic microorganisms. In an
attempt to circumvent the need for larger enzyme loadings, a simultaneous physical and enzymatic hydrolysis treatment was
evaluated. A ball-mill reactor was used as the digestion vessel, and the extent and rate of hydrolysis were monitored. Concurrently,
enzyme adsorption profiles and the rate of conversion during the course of hydrolysis were monitored. α-Cellulose, employed
as a model substrate, and SO2-impregnated steam-exploded Douglas-fir wood chips were assessed as the cellulosic substrates. The softwood-derived substrate
was further posttreated with water and hot alkaline hydrogen peroxide to remove >90% of the original lignin. Experiments at
different reaction conditions were evaluated, including substrate concentration, enzyme loading, reaction volumes, and number
of ball beads employed during mechanical milling. It was apparent that the best conditions for the enzymatic hydrolysis of
α-cellulose were attained using a higher number of beads, while the presence of air-liquid interface did not seem to affect
the rate of saccharification. Similarly, when employing the lignocellulosic substrate, up to 100% hydrolysis could be achieved
with a minimum enzyme loading (10 filter paper units/g of cellulose), at lower substrate concentrations and with a greater
number of reaction beads during milling. It was apparent that the combined strategy of simultaneous ball milling and enzymatic
hydrolysis could improve the rate of saccharification and/or reduce the enzyme loading required to attain total hydrolysis
of the carbohydrate moieties. 相似文献
9.
Statistical Optimization of Recycled-Paper Enzymatic Hydrolysis for Simultaneous Saccharification and Fermentation Via Central Composite Design 总被引:1,自引:0,他引:1
Qing Liu Ke-ke Cheng Jian-an Zhang Jin-ping Li Ge-hua Wang 《Applied biochemistry and biotechnology》2010,160(2):604-612
A central composite design of the response surface methodology (RSM) was employed to study the effects of temperature, enzyme
concentration, and stirring rate on recycled-paper enzymatic hydrolysis. Among the three variables, temperature and enzyme
concentration significantly affected the conversion efficiency of substrate, whereas stirring rate was not effective. A quadratic
polynomial equation was obtained for enzymatic hydrolysis by multiple regression analysis using RSM. The results of validation
experiments were coincident with the predicted model. The optimum conditions for enzymatic hydrolysis were temperature, enzyme
concentration, and stirring rate of 43.1 °C, 20 FPU g−1 substrate, and 145 rpm, respectively. In the subsequent simultaneous saccharification and fermentation (SSF) experiment under
the optimum conditions, the highest 28.7 g ethanol l−1 was reached in the fed-batch SSF when 5% (w/v) substrate concentration was used initially, and another 5% added after 12 h fermentation. This ethanol output corresponded
to 77.7% of the theoretical yield based on the glucose content in the raw material. 相似文献
10.
Traditionally, as much as 80% or more of an ethanol fermentation broth is water that must be removed. This mixture is not
only costly to separate but also produces a large aqueous stream that must then be disposed of or recycled. Integrative approaches
to water reduction include increasing the biomass concentration during fermentation. In this paper, experimental results are
presented for the rheological behavior of high-solids enzymatic cellulose hydrolysis and ethanol fermentation for biomass
conversion using Solka Floc as the model feedstock. The experimental determination of the viscosity, shear stress, and shear
rate relationships of the 10 to 20% slurry concentrations with constant enzyme concentrations are performed with a variable
speed rotational viscometer (2.0 to 200 rpm) at 40 °C. The viscosities of enzymatic suspension observed were in range of 0.0418
to 0.0144, 0.233 to 0.0348, and 0.292 to 0.0447 Pa s for shear rates up to 100 reciprocal seconds at 10, 15, and 20% initial
solids (w/v), respectively. Computational fluid dynamics analysis of bioreactor mixing demonstrates the change in bioreactor
mixing with increasing biomass concentration. The portion-loading method is shown to be effective for processing high-solids
slurries. 相似文献
11.
Jian Du Yuanyuan Li Hongman Zhang Hongbo Zheng He Huang 《Cellulose (London, England)》2014,21(4):2409-2417
The enzymatic hydrolysis of lignocelluloses is a key step in the production of ethanol. Economic considerations for large-scale implementation of the process require operation at high solid concentrations. However, the decrease in cellulose conversion offsets the advantages of working at high solid concentrations. The conversion showed a linear decrease in the reaction of pretreated corn stover (PCS) from 2 to 20 % (w/w) and filter paper from 1 to 10 % (w/w) initial total solid content. Hydrolysis experiments with PCS at various mixing speeds showed that the mass transfer limitation could not restrict the cellulose conversion except the solid concentrations over 5 % DM(w/w). The lignin, if added separately, does not correspond directly to the decrease. At increased concentrations, furfural and 5-hydroxymethylfurfural played a part in the effect, and 5-hydroxymethylfurfural only affected exoglucanase. Product inhibition caused by glucose accumulation at increased solid concentrations was found to be a significant and perhaps principal factor. The decrease in yield was caused by the synergetic inhibition, which was more serious with increased solid concentrations. 相似文献
12.
The pretreatment of lignocellulosic materials prior to the enzymatic hydrolysis is essential to the sugar yield and bioethanol
production. Dilute acid hydrolysis of black spruce softwood chip was performed in a continuous high temperature reactor followed
with steam explosion and mechanical refining. The acid-soaked wood chips were pretreated under different feeding rates (60
and 92 kg/h), cooking screw rotation speeds (7.2 and 14.4 rpm), and steam pressures (12 and 15 bar). The enzymatic hydrolysis
was carried out on the acid-insoluble fraction of pretreated material. At lower feeding rate, the pretreatment at low steam
pressure and short retention time favored the recovery of hemicellulose. The pretreatment at high steam pressure and longer
retention time recovered less hemicellulose but improved the enzymatic accessibility. As a result, the overall sugar yields
became similar no matter what levels of the retention time or steam pressure. Comparing with lower feeding rate, higher feeding
rate resulted in consistently higher glucose yield in both liquid fraction after pretreatment and that released after enzymatic
hydrolysis. 相似文献
13.
Wheat straw was pretreated by wet explosion using three different oxidizing agents (H2O2, O2, and air). The effect of the pretreatment was evaluated based on glucose and xylose liberated during enzymatic hydrolysis.
The results showed that pretreatment with the use of O2 as oxidizing agent was the most efficient in enhancing overall convertibility of the raw material to sugars and minimizing
generation of furfural as a by-product. For scale-up of the process, high dry matter (DM) concentrations of 15–20% will be
necessary. However, high DM hydrolysis and fermentation are limited by high viscosity of the material, higher inhibition of
the enzymes, and fermenting microorganism. The wet-explosion pretreatment method enabled relatively high yields from both
enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF) to be obtained when performed on unwashed slurry
with 14% DM and a low enzyme loading of 10 FPU/g cellulose in an industrial acceptable time frame of 96 h. Cellulose and hemicellulose
conversion from enzymatic hydrolysis were 70 and 68%, respectively, and an overall ethanol yield from SSF was 68%. 相似文献
14.
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
15.
Hensirisak P Parasukulsatid P Agblevor FA Cundiff JS Velander WH 《Applied biochemistry and biotechnology》2002,101(3):211-227
A laboratory-scale microbubble dispersion (MBD) generator was shown to improve oxygen transfer to aerobic microorganisms when
coupled to the conventional air-sparger. However, the process was not demonstrated on a large scale to prove its practical
application. We investigated the scale-up of a spinning-disk MBD generator for the aerobic fermentation of Saccharomyces cerevisiae (baker’s yeast). A 1-L spinning-disk MBD generator was used to supply air for 1- and 50-L working volume fermentation of
baker’s yeast. For the two levels investigated, the MBD generator maintained an adequate supply of surfactant-stabilized air
microbubbles to the microorganisms at a relatively low agitation rate (150 rpm). There was a significant improvement in oxygen
transfer to the microorganism relative to the conventional sparger. The volumetric mass transfer coefficient, k
L
a, for the MBD system at 150 rpm was 765 h−1 compared to 937 h−1 for the conventional sparger at 500 rpm. It is plausible to surmise that fermentation using larger working volumes may further
improve the k
L
a values and the dissolved oxygen (DO) levels because of longer hold-up times and, consequently, improve cell growth. There
was no statistically significant difference between the cell mass yield on substrate (0.43 g/g) under the MBD regime at an
agitation rate of 150 rpm and that achieved for the conventional air-sparged system (0.53 g/g) at an agitation rate of 500
rpm. The total power consumption per unit volume of broth in the 50-L conventional air-sparged system was threefold that for
the MBD unit for a similar product yield. Practical application of the MBD technology can be expected to reduce power consumption
and therefore operating costs for aerobic fermentation. 相似文献
16.
Biodiesel fuel is an alternative and renewable energy source, which may help to reduce air pollution, as well as our dependence
on petroleum for energy. Several processes have already been developed for the production of biodiesel. Alkali-catalyzed transesterification
with short-chain alcohols, for example, generates high yields of methyl esters in short reaction times. In this study, we
have evaluated the efficacy of batch (one- and two-stage) transesterification of rapeseed oil in the production of rapeseed
methyl ester. The conversion of rapeseed oil exhibited similar reaction patterns and yields in 30- and 1-L reaction systems.
Approximately 98% of the rapeseed oil was converted at 400 rpm within 20 min, under the following conditions: 1% (w/w) KOH,
1∶10 methanol molar ratio, and at 60°C. In the 30-L, two-stage transesterification process, approx 98.5% of the rapeseed oil
was converted at a 1∶4.5 molar ratio and 1% (w/w) KOH at 60°C for 30 min (first reaction condition), and at a 1∶1 molar ratio
and 0.2% (w/w) KOH at 60°C for 30 min (second reaction condition). 相似文献
17.
Jihane Zeghlouli Gwendoline Christophe Amine Guendouz Cherkaoui El Modafar Abdeljalil Belkamel Philippe Michaud Cdric Delattre 《Molecules (Basel, Switzerland)》2021,26(9)
Argan pulp is an abundant byproduct from the argan oil process. It was investigated to study the feasibility of second-generation bioethanol production using, for the first time, enzymatic hydrolysis pretreatment. Argan pulp was subjected to an industrial grinding process before enzymatic hydrolysis using Viscozyme L and Celluclast 1.5 L, followed by fermentation of the resulting sugar solution by Saccharomyces cerevisiae. The argan pulp, as a biomass rich on carbohydrates, presented high saccharification yields (up to 91% and 88%) and an optimal ethanol bioconversion of 44.82% and 47.16% using 30 FBGU/g and 30 U/g of Viscozyme L and Celluclast 1.5 L, respectively, at 10%w/v of argan biomass. 相似文献
18.
Catalytic conversion of cellulose into 5-hydroxymethylfurfural in high yields via a two-step process
Xinhua Qi Masaru Watanabe Taku M. Aida Richard L. SmithJr. 《Cellulose (London, England)》2011,18(5):1327-1333
As a key renewable chemical for plastics and fine chemicals, the preparation of 5-hydroxymethylfurfural (5-HMF) from biomass
is an important research topic. Cellulose, although abundant in nature, is difficult to convert to 5-HMF in good yields due
to its recalcitrant and heterogeneous nature. In this work, we show an efficient two-step process for converting microcrystalline
cellulose into 5-HMF with ionic liquids under mild conditions. In the first step, high glucose yields of above 80% could be
obtained from the cellulose hydrolysis by a strong acidic cation exchange resin in 1-ethyl-3-methyl imidazolium chloride ([EMIM][Cl])
with gradual addition of water. In the second step, the resin was separated from the reaction mixture and CrCl3 was added which lead to a 5-HMF yield of 73% based on cellulose substrate. The strategy can allow practical conversion of
biomass into bio-derived products. 相似文献
19.
As technologies for utilizing biomass for fuel and chemical production continue to improve, enzymatic hydrolysis can be run at still higher solids concentrations. For hydrolyses that initially contain little or no free water (10-40% total solids, w/w), the saccharification of insoluble polymers into soluble sugars involves changes of volume, density, and proportion of insoluble solids. This poses a new challenge when determining the degree of hydrolysis (conversion yield). Experiments have shown that calculating the yield from the resulting sugar concentration in the supernatant of the slurry and using the assumed initial volume leads to significant overestimations of the yield. By measuring the proportion of insoluble solids in the slurry as well as the sugar concentration and specific gravity of the aqueous phase, it is possible to precisely calculate the degree of conversion. The discrepancies between the different ways of calculating yields are demonstrated along with a nonlaborious method for approximating yields in high solids hydrolysis. 相似文献
20.
Current technology for conversion of biomass to ethanol is an enzyme-based biochemical process. In bioethanol production,
achieving high sugar yield at high solid loading in enzymatic hydrolysis step is important from both technical and economic
viewpoints. Enzymatic hydrolysis of cellulosic substrates is affected by many parameters, including an unexplained behavior
that the glucan digestibility of substrates by cellulase decreased under high solid loadings. A comprehensive study was conducted
to investigate this phenomenon by using Spezyme CP and Avicel as model cellulase and cellulose substrate, respectively. The
hydrolytic properties of the cellulase under different substrate concentrations at a fixed enzyme-to-substrate ratio were
characterized. The results indicate that decreased sugar yield is neither due to the loss of enzyme activity at a high substrate
concentration nor due to the higher end-product inhibition. The cellulase adsorption kinetics and isotherm studies indicated
that a decline in the binding capacity of cellulase may explain the long-observed but little-understood phenomenon of a lower
substrate digestibility with increased substrate concentration. The mechanism how the enzyme adsorption properties changed
at high substrate concentration was also discussed in the context of exploring the improvement of the cellulase-binding capacity
at high substrate loading. 相似文献