Corn Stover Particles Research Articles

Innovative Pavement Materials: Utilizing Corn Stover and Fly Ash in Geopolymers

The development of each nation is evaluated by its infrastructure, and each nation is competing with the others in infrastructure advancement, especially in the construction of roadways, since they play a vital role in the economic and social development of the nation. The conventional materials used for road construction are concrete and asphalt, which pose significant environmental challenges. This research gives insight into the potential of fly ash (FA) and corn stover (CS) in synthesizing geopolymer, as an alternative material for the construction of roads. This study examines the impact of three FA and CS mixture percentages and the particle size of CS on the compressive strength and porosity of geopolymer. The results indicate that incorporating larger amounts of CS in fly ash-based geopolymer may decrease the compressive strength of the geopolymer. Smaller CS particle sizes also tend to lead to lower compressive strength. Porosity of the geopolymer tended to increase with the incorporation of higher percentages of CS, particularly for smaller corn stover sizes. As a fine aggregate replacement for geopolymer, CS incorporation has the potential to reduce mined aggregate obtained from a process that harms the environment.

Effects of Corn Stover Particle Size on Growth Performance, Feeding Behavior and Nutrients Digestibility in Beetal Bucks

Background: The optimization of particle size of corn stover is necessary before it is being added in goat ration as it affects the uniformity and structural effectiveness of the diet, feed intake and digestion process in goats. Methods: A total of 24 bucks (10±1 months old; body weight of 20±1 kg) were selected and divided into three treatment groups of 8 bucks in each group in a Completely Randomized Design. Dietary treatments included conventional total mixed ration containing corn stover of three different particle sizes: 1) 8 mm;) CS8; 2) 16 mm, CS16 and 3) 24 mm, CS24. The experiment lasted for 15 weeks including 02 weeks of adaptability period. Result: The results indicated that particle size of corn stover significantly affected average daily gain (ADG) by bucks. The ADG was highest in the CS8 group. The bucks in the CS8 spent less time eating but numerically had higher dry matter intake.

Effect of natural biomass fillers on the stability, degradability, and elasticity of crop straws liquefied polyols‐based polyurethane foams

AbstractOilseed rape straw (OS), rice straw (RS), wheat straw (WS), and corn stover (CS) particles were used to reinforce bio‐polyols based polyurethane (PU) foams. The influence of crop straws (XS) fillers on the stability in water, degradability in soil, thermal stability, and elasticity of foams were investigated. The incorporation of OS and CS particles in the PU matrix increased the stability of reinforced foams in water, while the addition of WS and RS particles made foams lower stability in water. PU foams reinforced by XS particles displayed mass reductions up to 53.8% after burying in soil for 250 days. The reinforced foams were more stable under heating but the enhancement of thermal stability trended to disappear after water immersion or soil burying. The reinforced foams showed better elasticity that incorporations of OS and CS made PU foams higher height recovery percentage, while RS and WS made the recovery percentage decline firstly and then enhance during three times compressions. All these four XS particles are suitable to modify bio‐based PU foams, especially OS and CS particles appear to be more outstanding in preparing foams with higher stability in water, degradability in soil, thermal stability, and elasticity than RS and WS particles.

Effects of Wet Fermented Soybean Dregs on Physical and Mechanical Properties of Pellets of Corn Stover.

Simple SummaryCorn stover pellets are of poor quality (regarding physical and mechanical properties), and wet soybean dregs are viscous, which may improve the pelleting process. Furthermore, the soybean dregs have high nutritional value, which may increase the quality of feed. The relaxed density, dimensional stability coefficient and hardness of feed pellets were measured and analyzed in this study to clarify the influence mechanism of wet-fermented soybean dregs on the pelleting of corn stover. The results showed that fermented soybean dregs had a significant effect on corn stover pelleting. The comprehensive analysis showed that the addition of 5–10% fermented soybean dregs to corn stover improved the relaxed density, dimensional stability coefficient, and hardness of feed pellets by 10.76–23.51%, 7.32–15.74%, and 33.39–454.47%, respectively. The results could provide guidance on the research and development of high-quality forming technology and instruments using the mixture of corn stover and fermented soybean dregs and offer a new route for the utilization of high-moisture materials.Pelleting experiments were carried out in this study to clarify the influence mechanism of wet-fermented soybean dregs on the forming of corn stover. The effects of addition of water or wet fermented soybean dregs on the forming quality of corn stover were comparatively studied under different corn stover particle sizes and compression displacement. The fermented soybean dregs significantly affected the relaxed density, dimensional stability coefficient, and hardness of feed pellets. The relaxed density, dimensional stability coefficient, and hardness of feed pellets increased first and then decreased with the increase of fermented soybean dregs. The forming quality of corn stover added with fermented soybean dregs was higher than that of corn stover added with the same amount of water. The mechanism allowed soybean dregs to strengthen the bonding between corn stover particles and thus improved the quality of feed pellets. A certain amount of water was favorable for corn stover pelleting, but excessive water may decrease the quality of pellets. The comprehensive analysis showed that the addition of 5–10% fermented soybean dregs to the corn stover improved the relaxed density, dimensional stability coefficient, and hardness of feed pellets by 10.76–23.51%, 7.32–15.74%, and 33.39–454.47%, respectively.

Effect of Moisture and Feedstock Variability on the Rheological Behavior of Corn Stover Particles

Continuous feeding, processing, and handling of biomass powders is pivotal to the economic viability of integrated biorefineries. However, current challenges associated with the operational reliability of bulk solids handling and transport greatly impact the process economics and ultimately the widespread commercialization of integrated biorefineries. In this work, we examine the effect of moisture and feedstock variability on the flow behavior of corn stover biomass particles. The total flow energy, compressibility, shear properties, and wall friction angles were measured for corn stover samples A and B containing 0%, 15%, 25%, 50%, and 75% (mass fraction) moisture contents using a FT4 powder rheometer. In general, the flowability of both A and B was reduced when moisture was present as indicated by the stability and variable flow rate, compressibility, and shear tests. The 15% moisture sample had the highest flow energy, revealing the interplay between the increased surface tension and looser packing both of which were caused by liquid bridging. The 75% moisture sample had the highest compressibility and the lowest flowability factor (ffc). The trend in wall friction angle was found to be dependent upon the surface hydrophobicity of the wall material. The wall friction angle on the hydrophilic, stainless-steel surface increased with moisture and therefore poses additional handling challenges. On the other hand, the wall friction angle on the hydrophobic polymer surfaces were the lowest for samples with intermediate moisture contents. Sample B had greater bulk density, smaller compressibility, and greater flowability than the sample A, as suggested by the compressibility and shear tests. The wall friction angle of sample B was higher than or equal to that of sample A depending on both the type and the surface roughness of the wall material.

Mass Transport Limitations and Kinetic Consequences of Corn Stover Deacetylation

Alkaline pretreatment of herbaceous feedstocks such as corn stover prior to mechanical refining and enzymatic saccharification improves downstream sugar yields by removing acetyl moieties from hemicellulose. However, the relationship between transport phenomena and deacetylation kinetics is virtually unknown for such feedstocks and this pretreatment process. Here, we report the development of an experimentally validated reaction–diffusion model for the deacetylation of corn stover. A tissue-specific transport model is used to estimate transport-independent kinetic rate constants for the reactive extraction of acetate, hemicellulose and lignin from corn stover under representative alkaline conditions (5–7 g L−1NaOH, 10 wt% solids loadings) and at low to mild temperatures (4–70°C) selected to attenuate individual component extraction rates under differential kinetic regimes. The underlying transport model is based on microstructural characteristics of corn stover derived from statistically meaningful geometric particle and pore measurements. These physical descriptors are incorporated into distinct particle models of the three major anatomical fractions (cobs, husks and stalks) alongside an unsorted, aggregate corn stover particle, capturing average Feret lengths of 917–1239 μm and length-to-width aspect ratios of 1.8–2.9 for this highly heterogeneous feedstock. Individual reaction–diffusion models and their resulting particle model ensembles are used to validate and predict anatomically-specific and bulk feedstock performance under kinetic-controlled vs. diffusion-controlled regimes. In general, deacetylation kinetics and mass transfer processes are predicted to compete on similar time and length scales, emphasizing the significance of intraparticle transport phenomena. Critically, we predict that typical corn stover particles as small as ∼2.3 mm in length are entirely diffusion-limited for acetate extraction, with experimental effectiveness factors calculated to be 0.50 for such processes. Debilitatingly low effectiveness factors of 0.021–0.054 are uncovered for cobs—implying that intraparticle mass transfer resistances may impair observable kinetic measurements of this anatomical fraction by up to 98%. These first-reported quantitative maps of reaction vs. diffusion control link fundamental insights into corn stover anatomy, biopolymer composition, practical size reduction thresholds and their kinetic consequences. These results offer a guidepost for industrial deacetylation reactor design, scale-up and feedstock selection, further establishing deacetylation as a viable biorefinery pretreatment for the conversion of lignocellulosics into value-added fuels and chemicals.

Impact of corn stover particle size and C/N ratio on reactor performance in solid-state anaerobic co-digestion with dairy manure

ABSTRACTGreen energy generation from agricultural waste has the potential to minimize dependency on fossil and reduce the resultant environmental impact of this fuel provided anaerobic reactor performance is optimized. Hence, the interactive impact of carbon to nitrogen (C/N) ratio, particle size, and co-digestion of dairy manure (DM) and corn stover (CS) on solid-state anaerobic digester (SSAD) performance was investigated with four treatments (DMCS24S, DMCS24L, DMCS28L, and DMCS32L) in this solid-state study. Novel scanning electron microscope (SEM) image analysis utilized to describe the corn stover using ImageJ indicated that corn stover of particle size 0.18–0.42 mm had lower rough surface texture relative to the 0.42–0.84 mm size. This observation not only influenced the ingestate degradation, the bioconversion rate was negatively affected by 0.18–0.42 mm particle size of corn stover. Notably, increase in C/N ratio led to decrease in total ammonia nitrogen (TAN) and alkalinity concentration (Alk), hence, treatments with the lowest C/N ratio had better reactor performance in terms of suitable process parameters such as Alk, pH, ORP, and TAN. Furthermore, DMCS24L treatment had the highest methane yield (106 mL/g VS) and net methane energy (2.92 MJ/kg). Interestingly, modified Gompertz model gave the best kinetic description of the methane production. This SSAD mesophilic study suggests that corn stover, with particle size of 0.42–0.84 mm, co-digested with dairy manure under a C/N ratio of 24 has the potential to enhance methane yield and optimize reactor performance.Implications: The utilization of agricultural waste for bioenergy generation through solid-state anaerobic digestion could be enhanced through the interactive impact of substrate particle size, carbon-to-nitrogen (C/N) ratio and co-digestion, which has not been previously studied. These ternary factors significantly improved reactor performance and enhanced methane yield when corn stover of 0.42–0.84 mm particle size was co-digested with dairy manure to achieve a C/N ratio of 24.

Quantification of morphochemical changes during in situ enzymatic hydrolysis of individual biomass particles based on autofluorescence imaging.

Enzymatic hydrolysis of biomass is an established method for producing biofuels. Lignocellulosic biomass such as corn stover is very inhomogeneous material with big variation on conversion rates between individual particles therefore leading to variable recalcitrance results. In this study, we used noninvasive optical microscopy techniques, such as two‐photon microscopy and fluorescence lifetime imaging microscopy, to visualize and analyze morphological and chemical changes of individual corn stover particles pretreated with sulfuric acid during hydrolysis. Morphochemical changes were interpreted based on the fluorescence properties of isolated building blocks of plant cell wall, such as cellulose, hemicellulose, and lignin. Enzymatic hydrolysis resulted in particle size reduction, side wall collapse, decrease of second harmonic signal from cellulose, redshifting of autofluorescence emission, and lifetime decrease attributed to the relative increase of lignin. Based on these observations, tracking compositional change after hydrolysis of individual particles was accomplished. The methodologies developed offer a paradigm for imaging and analyzing enzymatic hydrolysis in vitro and in situ, which could be used for screening enzymes cocktails targeting specific recalcitrant structures or investigating locally enzyme anti‐inhibitory agents.

Study of Corn Stover Particle Size Distribution Characteristics for Knife Mill and Hammer Mill

Corn stover is a major agricultural biomass feedstock. The particle size distribution (PSD) of ground corn stover is important for biomass to bioenergy conversion. The objectives of this study were to evaluate Rosin-Rammler (RR) distribution, normal distribution and lognormal distribution on analysing PSD of corn stover grinded by knife mill and hammer mill, and to compare the grinding performance for knife mill and hammer mill. RR distribution model provided the best fitting results (0.998⩽Adj.R2⩽1) to the ground corn stover among the three PSD distribution models. The grinding performance based on the characteristic parameters (geometric mean diameter, geometric standard deviation, RR distribution parameter) analysis for the knife mill is better than the hammer mill for grinding corn stover under the same conditions.

Assessing the potential of facile biofuel production from corn stover using attrition mill treatment

Lignocellulosic biomass can be used for producing biochemicals and biofuels through a sugar platform. However, the required pretreatment processes and hydrolysate conditioning typically involve high operational and installation costs. This study investigated the possibility of facile biofuel production using an attrition mill. After milling for one hour, 73.5% (w/w) of corn stover particles had diameters of less than 100 µm, with a mean diameter of 61.3 ± 3.3 µm. Attrition milling of corn stover produced only 0.39 ± 0.01 g L−1 soluble phenolic compounds. The enzymatic conversion of corn stover particles less than 100 µm was 79.8% after 72 h enzymatic hydrolysis. The hydrolysate (i.e., natural sugar) was not inhibitory towards the growth of Saccharomyces cerevisiae. The attrition mill did not require high temperature or pressure conditions and did not inhibit cell growth. Therefore, when the attrition mill is used for pretreatment, a simple biofuel process that does not require washing, detoxification, and solvent recovery could be feasible.

Enhanced Production of 6-(N-Hydroxyethyl)-Amino-6-Deoxy-α-L-Sorbofuranose by Immobilized Gluconobacter oxydanson Corn Stover with a pH Control Strategy in a Bubble Column Bioreactor.

6-(N-Hydroxyethyl)-amino-6-deoxy-α-L-sorbofuranose (6NSL) is a key intermediate in the synthesis of miglitol. Biotransformation of N-2-hydroxyethyl glucamine (NHEG) to 6NSL was performed by immobilized Gluconobacter oxydans, which was prepared by cultivating the cells in a home-made bubble column bioreactor where corn stover particles were loaded. The optimal carrier addition and aeration rate for 6NSL production by immobilized cells in the bioreactor were determined to be 25g/L and 2.5vvm respectively. The supplementation of NH4Cl was conducive to the biotransformation of NHEG and was performed by adding aqueous ammonia and HCl, which was taken as the pH controlling agents as well. An optimal pH control strategy using the mixture of aqueous ammonia and NaOH was applied, resulting in a 9.9% increased production of 6NSL, while repeated batches of biotransformation increased from three times to four times. Finally, the 6NSL concentration and the conversion rate of NHEG to 6NSLreached 44.2 ± 1.5g/L and 88.4 ± 2.0%, respectively, in average after four cycles of biotransformation under the optimized condition.

Effects of water content on ball milling pretreatment and the enzymatic digestibility of corn stover

Lignocellulosic biomass pretreatment is a key step to determine the efficacy of biofuel production because of the recalcitrance of lignocellulosic feedstock. The effects of various water inputs, i.e., 0, 25, 100, and 400% (w/w), on the ball milling pretreatment of corn stover and enzymatic hydrolysis were studied under two milling temperatures (80 °C and 100 °C) and three milling times (10, 20, and 30 min). Ball milling reduced corn stover particle size and disrupted the rigid cell wall matrix. As milling time increased, corn stover size decreased remarkably. Changes in corn stover were analyzed using size distribution graphs and geometric mean diameter with respect to milling temperature and time. Milling with 0% (w/w) water resulted in the rapid grinding of corn stover. The highest glucose yield (66.96%) was obtained after milling at 80 °C for 30 min with no water. The corn stovers milled with 0% or 25% (w/w) water showed higher glucose yields when milled at 80 °C than at 100 °C, while the samples milled with 100% or 400% (w/w) water showed higher glucose yields at 100 °C. Finally, several ball milling conditions were proposed to construct a combinational pretreatment process based on the study results. These results provide a basis for minimizing water use during lignocellulosic biofuel production and improving sustainability.

Beta-Glucosidase Production Optimization from Newly Isolated Aspergillus tubingensis IMMIS2 Using Taguchi Statistical Design

Fungal production of beta-glucosidase was optimized by Taguchi statistical method using corn stover as substrate. Taguchi statistical design depicted the highest glucosidase activity (116 μg mL−1 min−1) by Aspergillus tubingensis IMMIS2 using 5 g of 80-mm mesh-sized substrate with 50% moisture contents, 0.1 g of urea, 0.2 g of KCl, 0.3 g of CaCl2, 0.01 g of MgSO4 and 3 mL of the fungal culture as inoculum. Main effect plot for SN ratio exposed that some parameters (corn stover as substrate, corn stover particle size, urea level and CaCl2) had significant effect on cellulase production as compared to some other parameters (inoculum size, KCl and MgSO4 levels). Our findings of the present study will be helpful for cost-effective and optimum production of commercially important enzymes using agro-industrial wastes as growth substrates.

Concentrated HCl Catalyzed 5-(Chloromethyl)furfural Production from Corn Stover of Varying Particle Sizes

5-(Chloromethyl) Furfural (CMF) is a potential chemical building block for replacing petroleum-derived chemicals derived from lignocellulosic feedstocks. In this study, hand harvested corn stover and mechanically forage chopped corn stover was processed in a 1 L hydrolysis reactor to produce CMF in a biphasic, two solvent system. Both 1,2 dichloroethane (DCE) and dichloromethane (DCM) were tested as organic solvents. The results showed that DCE performed better than DCM due to temperature and pressure limitations of the reactor system. Using DCE as the extracting solvent, the effects of solids loading, particle size, and moisture content of the corn stover on the hydrolysis efficiency were determined. One liter acid hydrolysis reactor provides consistent and reproducible yields of 63% CMF from hand harvested corn stover as feedstock at solid loading of 10% wt/v, 100C for 1 h. For the forage chopped corn stover, increasing particle size brings an increase in the feedstock sugar content. Foraged chopped corn stover (FCCS) particle sizes larger than 19 mm (0.75 in.) results in significant reduction in CMF yield from 43 to 35%.

Granular Flow of Corn Stover Particles in a Helical Ribbon Stirred Tank

Abstract The flow characteristics and power consumption of corn stover particles in a helical ribbon stirred tank was investigated in the context of simultaneous saccharification and fermentation of corn stover at high solids loading. It was found that the particles in the tank can be divided into conveyed material and core material according to their flow characteristics. The flow of the former materials was frictional regime and the latter was intermediate flow; the conveyed material avalanched into the core at the top of granular bed. The granular bed dilated when the impeller was rotating, which was beneficial for the entrance of liquid enzyme into the solid phase and for the successful proceeding of the saccharification of the corn stover. The power of granular mixing was linearly proportional to the impeller rotational speed due to the discrete characteristic of the particles and flow dynamics of the conveyed material. The ratio of power consumption to the impeller rotational speed (P/N) was linear proportional to loading ratio and the dimensionless torque (M/mgR) was 0.48. The power consumption increased first and then decreased as the corn stover particles evolved from granular/wet granular to paste/slurry. The maximum power consumption was at 83 % (w/w) moisture content.

Production, Characterization and Application of a Xylanase from Streptomyces sp. AOA40 in Fruit Juice and Bakery Industries

ABSTRACTStreptomyces sp. AOA40, which produces halotolerant and thermotolerant xylanase, was isolated from Mersin soil. Various carbon sources were tested for xylanase production with selected fermentation medium. The best carbon source was selected as corn stover. The effect of corn stover concentration and particle size, composition of fermentation medium, fermentation condition such as initial pH and agitation rate on xylanase production was determined. After production, xylanase was partially purified with ion-exchange chromatography and gel filtration chromatography for characterization of xylanase and application in fruit juice and dough improvement. The optimum pH for the activity of xylanase occurred at pH 6.0 in phosphate buffer, while the optimum temperature was 60°C. The relative xylanase activity in the pH ranges of 4–9 remained between 59.93 and 54.43% of the activity at pH 6.0 (100.00%). The xylanase activity showed a half-life of 172 min at 70°C, which was reduced to 75 min at 80°C. The enzyme was highly inhibited by 10–100 mM of Hg+2, EDTA, Mg+2, SDS and 100 mM Cu+2. Clarity of fruit juices increased after enzymatic treatment of apple (17.85%), grape (17.19%) and orange juice (18.36%) with partially purified xylanase and also reducing sugar concentrations of these fruit juices were improved by 17.21, 16.79 and 19.57%, respectively. Also, dough volume was raised 17.06% with using partially purified Streptomyces sp. AOA40 xylanase in bread making.

Optimized design and experiment on ring mold pelletizer for producing biomass fuel pellets

The forming process of biomass fuel pellets using a ring mold pelletizer was analyzed, optimized, tested and evaluated in this study. The effects of stress amplitude and the stress ratio on the fatigue failure of the ring mold under 4-, 3-, and 2-roller designs were investigated. Depending on the calculation of stress amplitude acting on the ring mold, the 4-roller design was chosen for having the smallest value of stress amplitude in this condition. After determining the main design parameters, a three-dimensional model of the ring mold pelletizer was established based on the Pro/Engineer software, and the model was transferred into ADAMS software through Mechanism/Pro which is a dedicated interface software. The ADAMS software was used to run simulations. In order to obtain the highest efficiency and the lowest power consumption, the optimal result was the 4-roller design. Finally, a prototype of the ring mold pelletizer with four rollers was designed and manufactured for biomass fuel pellet production. Corn stover biomass was used as material for experimental manufacturing of fuel pellets. Test and evaluation showed that the optimized pellet durability was 99.79% with ground corn stover particles passing a screen size of 1.97 mm, moisture content of 21.2% w.b. and a material moisture conditioning time of 3.82 h. Pellets formed in the prototype ring mold pelletizer using corn stover had acceptable durability according to European standards. Keywords: biomass pellet, ring mold pelletizer, optimized design, biofuel, corn stover, Pro/Engineer, Adams, pellet durability DOI: 10.3965/j.ijabe.20160903.2074 Citation: Gao W, Tabil L G, Zhao R F, Liu D J. Optimized design and experiment on ring mold pelletizer for producing biomass fuel pellets. Int J Agric & Biol Eng, 2016; 9(3): 57－66.

Experimental investigations towards understanding important parameters in wet drum granulation of corn stover biomass

Biofeedstocks such as corn coproducts or biomass such as corn stover are typically densified in a dry process using pellet mills to enhance transportability and use as livestock feed. Our work presents data of an experimental study using a non-traditional means, wet granulation with a lab-scale rotary drum granulator to determine key parameters that affect granule properties and yield of desirable sized granules. Granules were manufactured from corn stover and two liquid coproducts from corn bioprocessing, corn steep liquor (CSL) and corn molasses (CM) by varying corn stover particle size, corn stover:coproduct blend ratio and granulation residence time. The results showed that different formulation and processing parameters affected corn stover granulation. Granulation with an initial particle size of 0.88–0.96mm (from screen size 6.4mm), low liquid level (1:4) with CM, and short residence time (0.5min) could be used to produce desirable sized granules (1.78 to 7.87mm) for ruminant livestock feed with yields of over 98%. The effect of initial particle size of corn stover particles on density of granular products was significant. Corn stover particle size also positively influenced the granule size and negatively influenced yield of desirable granules. While increased coproduct (CM and CSL) levels in the blend increased the granule particle size and density, yield of desirable granules was reduced.

The flow of wheat straw suspensions in an open-impeller centrifugal pump

A laboratory-scale closed-circuit pipeline facility was modified to experimentally investigate the effects of pumping slurries of wheat straw and corn stover particles on the performance characteristics of a centrifugal slurry pumps. The effects of particle size and slurry solid mass content (concentration) on head, efficiency, and power consumption of a centrifugal slurry pumps were studied. In a clear contrast to the general performance of centrifugal slurry pumps in conventional solid–liquid systems, the total head height increased with an increase in slurry solid mass content due to several reasons including unique friction loss behavior (i.e., drag reducing feature) of fibrous particles slurries in pipelines. In addition, small size fibrous particles increased the pump efficiency more than the efficiency of the same pump handling pure water only. A correlation was finally proposed to predict the reduction in head while centrifugally pumping fibrous agricultural residue biomass (wheat straw, corn stover) slurries, compared to the head produced while handling pure water only. The results could be used in the design and operation of centrifugal slurry pumps to transport fibrous agricultural residue biomass materials. However, the effects of other parameters like air in the system and anaerobic problems should be taken into account too.

Analysis of particle size reduction on overall surface area and enzymatic hydrolysis yield of corn stover.

Particle size of lignocellulose materials is an important factor for enzymatic hydrolysis efficiency. In this study, corn stover was milled and sieved into different size fractions from 1.42, 0.69, 0.34, to 0.21mm, and the corresponding enzymatic hydrolysis yields were 24.69, 23.96, 25.34, and 26.97%, respectively. The results indicate that the hydrolysis yield is approximately constant with changing corn stover particle sizes in the experimental range. The overall surface area and the inner pore size measurement show that the overall specific surface area was less than 2% with the half reduction of particle size due to the greater inner pore surface area. The scanning electron microscope photographs gave direct evidence of the much greater inner pore surface area of corn stover particles. This result provided a reference when a proper size reduction of lignocellulose materials is considered in biorefining operations.