Phytosterols and their derivatives: Structural diversity, distribution, metabolism, analysis, and health-promoting uses.

Phytosterols (plant sterols) occur in the cells of all plants. They are important structural components that stabilize the biological membranes of plants. Sterols can occur in the "free" unbound form or they can be covalently bound via an ester or glycosidic bond. Since our previous 2002 review on phytosterols and phytosterol conjugates, phytosterol glucosides have been found to be important structural components in the lipid rafts of the plasma membrane of plant cells, where they are thought to be essential to the function of plasma membrane enzymes and perhaps other proteins. Phytosterols also serve as precursors in the synthesis of important bioactive compounds such as steroidal saponins, steroidal glycoalkaloids, phytoecdysteroids, and brassinosteroids. Methods for the analysis of phytosterols range from traditional gas chromatography of free phytosterols to modern sophisticated forms of mass spectrometry which have been used for the new field of sterol lipidomics, sometimes called "sterolomics." Phytosterol-enriched functional foods first appeared about twenty years ago and many clinical studies have confirmed the low density lipoprotein (LDL) cholesterol-lowering properties of various types of phytosterols. In recent years additional clinical studies and more than ten important meta-analyses have provided insights to better understand the cholesterol-lowering and other biological effects of plant sterols.

Isolation of barley hulls and straw constituents and study of emulsifying properties of their arabinoxylans.

Both barley hulls and straw contain valuable arabinoxylans and other useful carbohydrate and non-carbohydrate components. The functional water soluble non-caloric arabinoxylan (hemicellulose B) fraction was isolated from hot water-extracted and de-starched barley hulls and straws by an alkaline hydrogen peroxide extraction followed by ethanol precipitation. Barley hulls contained comparatively more Hemi. B (20.51%) than barley straws (7.41 to 12.94%). The sugar composition of Hemi. B showed that they were typical arabinoxylans containing (in addition to arabinose and xylose) some galactose, glucose and acidic sugars in the side chains. The hemicellulose B fractions from barley straws were superior oil-in-water emulsifiers than those from barley hulls. These Hemi. B fractions contain protein, which contributes to their emulsions stabilizing property.

Protein/arabinoxylans gels: effect of mass ratio on the rheological, microstructural and diffusional characteristics.

Wheat bran arabinoxylan (WBAX) gels entrapping standard model proteins at different mass ratios were formed. The entrapment of protein affected the gel elasticity and viscosity values, which decreased from 177 to 138 Pa. The presence of protein did not modify the covalent cross-links content of the gel. The distribution of protein through the network was investigated by confocal laser scanning microscopy. In mixed gels, protein aggregates forming clusters were detected at protein/polysaccharide ratios higher than 0.25. These clusters were not homogeneously distributed, suggesting that WBAX and protein are located in two different phases. The apparent diffusion coefficient (Dm) of proteins during release from mixed gels was investigated for mass ratios of 0.06 and 0.12. For insulin, Dm increased significantly from 2.64 × 10-7 to 3.20 × 10-7 cm2/s as the mass ratio augmented from 0.06 to 0.12. No significant difference was found for Dm values of ovalbumin and bovine serum albumin released from the mixed gels. The results indicate that homogeneous protein/WBAX gels can be formed at low mass ratios, allowing the estimation of Dm by using an analytical solution of the second Fick's law.

A comparison of two milling strategies to reduce the mycotoxin deoxynivalenol in barley.

Winter barley (Hordeum vulgare L.), a potential feedstock for fuel ethanol production, may be contaminated with the trichothecene mycotoxin deoxynivalenol (DON). DON is a threat to feed and food safety in the United States and may become concentrated during the production of distillers dried grains with solubles (DDGS). DDGS is a coproduct of fuel ethanol production and is increasingly being used as feed for domestic animals. Therefore, new strategies to reduce the threat of DON in DDGS need to be developed and implemented for grain destined for fuel ethanol production. It is known that large concentrations of DON accumulate in the hulls of wheat and barley. Consequently, improved methods are needed to carefully remove the hull from the grain and preserve the starchy endosperm. Whole kernels from five Virginia winter barley genotypes were used to evaluate the abilities of two different milling strategies (roller milling and precision milling (FitzMill)) for their ability to remove the hull-enriched tissue from the kernel while maintaining starch levels and reducing DON levels in the endosperm-enriched tissue. After whole kernels were milled, DON and starch levels were quantified in the hull-enriched fractions and endosperm-enriched fractions. Initial milling experiments demonstrated that the precision mill system (6 min run time) is able to reduce more DON than the roller mill but with higher starch losses. The average percent DON removed from the kernel with the roller mill was 36.7% ± 5.5 and the average percent DON removed from the dehulled kernel with the precision mill was 85.1% ± 9.0. Endosperm-enriched fractions collected from the roller mill and precision mill contained starch levels ranging from 49.0% ± 12.1 to 59.1% ± 0.5 and 58.5% ± 1.6 to 65.3% ± 3.9, respectively. On average, the precision mill removed a mass of 23.1% ± 6.8 and resulted in starch losses of 9.6% ± 6.3, but produced an endosperm-enriched fraction with relatively very little average DON (5.5 ± 2.7 µg g(-1)). In contrast, on average, the roller mill removed a mass of 12.2% ± 1.6 and resulted in starch losses of 2.1% ± 0.5, but produced an endosperm-enriched fraction with high average DON (20.7 ± 13.5 µg g(-1)). In a time course precision milling experiment, we tested barley genotypes Nomini, Atlantic, and VA96-44-304 and attempted to reduce the starch loss seen in the first experiment while maintaining low DON concentrations. Decreasing the run time of the precision mill from 5 to 2 min, reduced starch loss at the expense of higher DON concentrations. Aspirated fractions revealed that the precision milled hull-enriched fraction contained endosperm-enriched components that were highly contaminated with DON. This work has important implications for the reduction of mycotoxins such as DON in barley fuel ethanol coproducts and barley enriched animal feeds and human foods.

Enzymatic fractionation of SAA-pretreated barley straw for production of fuel ethanol and astaxanthin as a value-added co-product.

Barley straw was used to demonstrate an integrated process for production of fuel ethanol and astaxanthin as a value-added co-product. Barley straw was pretreated by soaking in aqueous ammonia using the previously determined optimum conditions, which included 77.6 °C treatment temperature, 12.1 h treatment time, 15 wt% ammonia concentration, and 1:8 solid-to-liquid ratio. In the newly developed process, the pretreated barley straw was first hydrolyzed with ACCELLERASE® XY (a commercial hemicellulase product) to generate a xylose-rich solution, which contained 3.8 g/l glucose, 22.9 g/l xylose, and 2.4 g/l arabinose, with 96 % of the original glucan being left intact. The xylose-rich solution was used for production of astaxanthin by the yeast Phaffia rhodozyma without further treatment. The resulting cellulose-enriched solid residue was used for ethanol production in a fed-batch simultaneous saccharification and fermentation using ACCELLERASE® 1500 (a commercial cellulase product) and the industrial yeast Saccharomyces cerevisiae. At the end of the fermentation, 70 g/l ethanol was obtained, which was equivalent to 63 % theoretical yield based on the glucan content of the solid substrate.

Maximum production of fermentable sugars from barley straw using optimized soaking in aqueous ammonia (SAA) pretreatment.

Soaking in aqueous ammonia (SAA) pretreatment was investigated to improve enzymatic digestibility and consequently to increase total fermentable sugar production from barley straw. Various effects of pretreatment process parameters, such as reaction temperature, reaction time, solid:liquid ratio, and ammonia concentration, were evaluated, and the optimum conditions for two of the most important factors, reaction temperature and time were determined using response surface methodology. Optimized reaction conditions were 77.6 °C treatment temperature, 12.1 h. treatment time, 15 wt.% ammonia concentration, and 1:8 solid-to-liquid ratio, which gave a sugar recovery yield of 71.5 % (percent of theoretical sugar recovered from the untreated barley straw) with enzyme loading of 15 FPU/g-glucan. In the optimization of the SAA pretreatment process, ammonia concentration, reaction temperature, and reaction time were determined to be the most significant factors correlated to subsequent enzyme digestibility. Based on tested conditions exhibiting high sugar recovery yields of >60 %, it appeared that reaction temperature affected total fermentable sugar production more significantly than reaction time.

Compositional equivalence of barleys differing only in low- and normal-phytate levels.

Recent breeding advances have led to the development of several barley lines and cultivars with significant reductions (50% or greater) in phytate levels. Low-phytate (LP) grain is distinguished by containing not only a reduced level of phytate P but also an increased level of inorganic P, resulting in greater bioavailability of P and mineral cations in animal diets. It is important to determine whether other nutritional characteristics are altered by breeding for the low-phytate trait. This study was designed to investigate if breeding for reduced phytate content in barleys had any effect on the contents of other attributes measured by comparing mean and range values of the levels of protein, oil, ash, total carbohydrate, starch, and ß-glucan, fatty acid composition, and levels of tocopherols and tocotrienols between five LP and five normal-phytate barleys grown in three Idaho locations. Results show that only the phytate level in the LP group was substantially lower than that of the normal-phytate group and that all other attributes measured or calculated were substantially equivalent between the two groups of barleys. Therefore, the phytate level had little effect on the levels of protein, oil, ash, total carbohydrate, starch, and ß-glucan, fatty acid composition, and levels of tocopherols and tocotrienols in barley seeds.

Isolation, purification, and identification of protein associated with corn fiber gum.

Corn fiber gum (CFG), an alkaline hydrogen peroxide extract of the corn kernel milling byproduct "corn fiber", is a proteinaceous arabinoxylan with protein content ranging from ca. 2 to 9% by weight for CFG samples isolated from different corn milling fiber sources. Several studies have suggested that protein associated with CFG could be partly responsible for its excellent emulsifying properties in oil-in-water emulsion systems. Nevertheless, the composition and identity of the protein component has never been determined. In the present study, CFG was deglycosylated by treating with trifluoromethanesulfonic acid, and the resulting proteins were purified by passage through C18 solid phase extraction cartridges. The proteins were then separated and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The protein band from the gel was treated with a proteolytic enzyme, chymotrypsin, and the resulting peptides were cleaned using C18 Zip Tip pipet tips and analyzed using matrix-assisted laser desorption/ionization with automated tandem time-of-flight mass spectrometry. The partial sequences derived from the mass spectrometry analyses of the resulting chymotryptic peptides were found to be similar to the 22-kDa alpha-zein Z1 (az22z1) protein (a major storage protein in corn endosperm) when queried against the primary sequences from the National Center for Biotechnology Information database. This is the first report that this hydrophobic protein is associated with CFG and may explain why CFG is an excellent emulsifier for oil-in-water emulsion systems.

Conversion of deoxynivalenol to 3-acetyldeoxynivalenol in barley-derived fuel ethanol co-products with yeast expressing trichothecene 3-O-acetyltransferases.

BACKGROUND: The trichothecene mycotoxin deoxynivalenol (DON) may be concentrated in distillers dried grains with solubles (DDGS; a co-product of fuel ethanol fermentation) when grain containing DON is used to produce fuel ethanol. Even low levels of DON (≤ 5 ppm) in DDGS sold as feed pose a significant threat to the health of monogastric animals. New and improved strategies to reduce DON in DDGS need to be developed and implemented to address this problem. Enzymes known as trichothecene 3-O-acetyltransferases convert DON to 3-acetyldeoxynivalenol (3ADON), and may reduce its toxicity in plants and animals. RESULTS: Two Fusarium trichothecene 3-O-acetyltransferases (FgTRI101 and FfTRI201) were cloned and expressed in yeast (Saccharomyces cerevisiae) during a series of small-scale ethanol fermentations using barley (Hordeum vulgare). DON was concentrated 1.6 to 8.2 times in DDGS compared with the starting ground grain. During the fermentation process, FgTRI101 converted 9.2% to 55.3% of the DON to 3ADON, resulting in DDGS with reductions in DON and increases in 3ADON in the Virginia winter barley cultivars Eve, Thoroughbred and Price, and the experimental line VA06H-25. Analysis of barley mashes prepared from the barley line VA04B-125 showed that yeast expressing FfTRI201 were more effective at acetylating DON than those expressing FgTRI101; DON conversion for FfTRI201 ranged from 26.1% to 28.3%, whereas DON conversion for FgTRI101 ranged from 18.3% to 21.8% in VA04B-125 mashes. Ethanol yields were highest with the industrial yeast strain Ethanol Red®, which also consumed galactose when present in the mash. CONCLUSIONS: This study demonstrates the potential of using yeast expressing a trichothecene 3-O-acetyltransferase to modify DON during commercial fuel ethanol fermentation.

Pretreatment of corn stover using low-moisture anhydrous ammonia (LMAA) process.

A simple pretreatment method using anhydrous ammonia was developed to minimize water and ammonia inputs for cellulosic ethanol production, termed the low moisture anhydrous ammonia (LMAA) pretreatment. In this method, corn stover with 30-70% moisture was contacted with anhydrous ammonia in a reactor under nearly ambient conditions. After the ammoniation step, biomass was subjected to a simple pretreatment step at moderate temperatures (40-120°C) for 48-144 h. Pretreated biomass was saccharified and fermented without an additional washing step. With 3% glucan loading of LMAA-treated corn stover under best treatment conditions (0.1g-ammonia+1.0 g-water per g biomass, 80°C, and 84 h), simultaneous saccharification and cofermentation test resulted in 24.9 g/l (89% of theoretical ethanol yield based on glucan+xylan in corn stover).

Scale-up of ethanol production from winter barley by the EDGE (enhanced dry grind enzymatic) process in fermentors up to 300 l.

A fermentation process, which was designated the enhanced dry grind enzymatic (EDGE) process, has recently been developed for barley ethanol production. In the EDGE process, in addition to the enzymes normally required for starch hydrolysis, commercial ß-glucanases were used to hydrolyze (1,3)(1,4)-ß-D: -glucans to smaller molecules, thus reducing the viscosity of the mash to levels sufficiently low to allow transport and mixing in commercial equipment. Another enzyme, a developmental ß-glucosidase, then was used to hydrolyze the resulting oligomers to glucose, which subsequently was fermented to produce additional ethanol. The EDGE process was developed with Thoroughbred, a winter hulled barley, using a shake flask model. To move toward commercialization, it is necessary to prove that the developed process would be applicable to other barley varieties and also to demonstrate its scalability. Experiments were performed in 7.5, 70, and 300-l fermentors using Thoroughbred and Eve, a winter hull-less barley. It was shown that the process was scalable for both barley varieties. Low levels of glucose throughout the course of the fermentations demonstrated the high efficiency of the simultaneous saccharification and fermentation process. Final ethanol concentrations of 14% (v/v) were achieved for initial total solids of 28.5-30% (w/w), which gave an ethanol yield of 83-87% of the theoretical values. The distillers dried grains with solubles co-products contained very low levels of ß-glucans and thus were suitable for use in feed formulations for all animal species.

Economic analysis of fuel ethanol production from winter hulled barley by the EDGE (Enhanced Dry Grind Enzymatic) process.

A process and cost model was developed for fuel ethanol production from winter barley based on the EDGE (Enhanced Dry Grind Enzymatic) process. In this process, in addition to ß-glucanases, which are added to reduce the viscosity of the mash, ß-glucosidase is also added to completely hydrolyze the oligomers obtained during the hydrolysis of ß-glucans to glucose. The model allows determination of capital costs, operating costs, and ethanol production cost for a plant producing 40 million gallons of denatured fuel ethanol annually. A sensitivity study was also performed to examine the effects of ß-glucosidase and barley costs on the final ethanol production cost. The results of this study clearly demonstrate the economic benefit of adding ß-glucosidase. Lower ethanol production cost was obtained compared to that obtained without ß-glucosidase addition in all cases except one where highest ß-glucosidase cost allowance and lowest barley cost were used.

Consolidated conversion of hulled barley into fermentable sugars using chemical, thermal, and enzymatic (CTE) treatment.

A novel process using chemical, thermal, and enzymatic treatment for conversion of hulled barley into fermentable sugars was developed. The purpose of this process is to convert both lignocellulosic polysaccharides and starch in hulled barley grains into fermentable sugars simultaneously without a need for grinding and hull separation. In this study, hulled barley grains were treated with 0.1 and 1.0 wt.-% sulfuric acid at various temperatures ranging from 110 to 170 °C in a 63-ml flow-through packed-bed stainless steel reactor. After sulfuric acid pretreatment, simultaneous conversion of lignocellulose and starch in the barley grains into fermentable sugars was performed using an enzyme cocktail, which included α-amylase, glucoamylase, cellulase, and ß-glucosidase. Both starch and non-starch polysaccharides in the pre-treated barley grains were readily converted to fermentable sugars. The treated hulled barley grains, including their hull, were completely hydrolyzed to fermentable sugars with recovery of almost 100% of the available glucose and xylose. The pretreatment conditions of this chemical, thermal, and enzymatic (CTE) process for achieving maximum yield of fermentable sugars were 1.0 wt.% sulfuric acid and 110 °C. In addition to starch, the acid pretreatment also retained most of the available proteins in solid form, which is essential for subsequent production of fuel ethanol and high protein distiller's dried grains with solubles co-product.

Integration of succinic acid and ethanol production with potential application in a corn or barley biorefinery.

Production of succinic acid from glucose by Escherichia coli strain AFP184 was studied in a batch fermentor. The bases used for pH control included NaOH, KOH, NH(4)OH, and Na(2)CO(3). The yield of succinic acid without and with carbon dioxide supplied by an adjacent ethanol fermentor using either corn or barley as feedstock was examined. The carbon dioxide gas from the ethanol fermentor was sparged directly into the liquid media in the succinic acid fermentor without any pretreatment. Without the CO(2) supplement, the highest succinic acid yield was observed with Na(2)CO(3), followed by NH(4)OH, and lowest with the other two bases. When the CO(2) produced in the ethanol fermentation was sparged into the media in the succinic acid fermentor, no improvement of succinic acid yield was observed with Na(2)CO(3). However, several-fold increases in succinic acid yield were observed with the other bases, with NH(4)OH giving the highest yield increase. The yield of succinic acid with CO(2) supplement from the ethanol fermentor when NH(4)OH was used for pH control was equal to that obtained when Na(2)CO(3) was used, with or without CO(2) supplementation. The benefit of sparging CO(2) from ethanol fermentation on the yield of succinic acid demonstrated the feasibility of integration of succinic acid fermentation with ethanol fermentation in a biorefinery for production of fuels and industrial chemicals.

Continuous high-solids corn liquefaction and fermentation with stripping of ethanol.

Removal of ethanol from the fermentor during fermentation can increase productivity and reduce the costs for dewatering the product and coproduct. One approach is to recycle the fermentor contents through a stripping column, where a non-condensable gas removes ethanol to a condenser. Previous research showed that this approach is feasible. Savings of $0.03 per gallon were predicted at 34% corn dry solids. Greater savings were predicted at higher concentration. Now the feasibility has been demonstrated at over 40% corn dry solids, using a continuous corn liquefaction system. A pilot plant, that continuously fed corn meal at more than one bushel (25 kg) per day, was operated for 60 consecutive days, continuously converting 95% of starch and producing 88% of the maximum theoretical yield of ethanol. A computer simulation was used to analyze the results. The fermentation and stripping systems were not significantly affected when the CO(2) stripping gas was partially replaced by nitrogen or air, potentially lowering costs associated with the gas recycle loop. It was concluded that previous estimates of potential cost savings are still valid.

Preparation of antimicrobial membranes: coextrusion of poly(lactic acid) and Nisaplin in the presence of Plasticizers.

Nisin is a naturally occurring antimicrobial polypeptide and is popularly used in the food and food-packaging industries. Nisin is deactivated at temperatures higher than 120 degrees C and, therefore, cannot be directly incorporated into poly(L-lactic acid) (PLA), a biomass-derived biodegradable polymer, by coextrusion because PLA melts at temperatures around 160 degrees C or above. However, PLA can remain in a melt state at temperatures below the T(m) in the presence of lactic acid or other plasticizers. In the present study, PLA was coextruded with lactic acid, or lactide, or glycerol triacetate at 160 degrees C. After the PLA was melted, the temperature of the barrels was reduced to 120 degrees C, and then Nisaplin, the commercial formulation of nisin, was added and the extrusion was continued. The resultant extrudates possess the capability to suppress the growth of the pathogenic bacterial Listeria monocytogenes , demonstrating a significant antimicrobial activity. The present study provides a simple method to produce PLA-based antimicrobial membranes. The method can also be used for the coextrusion of other heat-sensitive substances and thermoplastics with high melting temperature.

Pretreatment and fractionation of corn stover by soaking in ethanol and aqueous ammonia.

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 degrees 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.

Fractionation, characterization, and study of the emulsifying properties of corn fiber gum.

Corn fiber gum (CFG) has been fractionated by hydrophobic interaction chromatography on Amberlite XAD-1180 resin using ionic, acidic, basic, and hydrophobic solvents of different polarities. Characterization, including determination of total carbohydrate, acidic sugar, and protein content, has been done for each fraction together with measurements of molar mass, polydispersity, radius of gyration, Mark-Houwink exponent, and intrinsic viscosity using multiangle laser light scattering and online viscosity measurements. Emulsification properties of all fractions in an oil-in-water emulsion system with 20:1 oil to gum ratio were studied by measuring turbidity over 14 days. The results indicate that CFG consists of different components differing in their molecular weights and carbohydrate and protein contents. The main fraction eluted with NaCl, although low in protein content, has the highest average molecular weight and was determined to be a better emulsifier than the other fractions. The unfractionated CFG, which contains different molecular species, is the best emulsifier.

Near-infrared analysis of whole kernel barley: comparison of three spectrometers.

This study was conducted to develop calibration models for determining quality parameters of whole kernel barley using a rapid and nondestructive near-infrared (NIR) spectroscopic method. Two hundred and five samples of whole barley grains of three winter-habit types (hulled, malt, and hull-less) produced over three growing seasons and from various locations in the United States were used in this study. Among these samples, 137 were used for calibration and 68 for validation. Three NIR instruments with different resolutions, one Fourier transform instrument (4 cm(-1) resolution), and two dispersive instruments (8 nm and 10 nm bandpass) were utilized to develop calibration models for six components (moisture, starch, beta-glucan, protein, oil, and ash) and the results were compared. Partial least squares regression was used to build models, and various methods for preprocessing of spectral data were used to find the best model. Our results reveal that the coefficient of determination for calibration models (NIR predicted versus reference values) ranged from 0.96 for moisture to 0.79 for beta-glucan. The level of precision of the model developed for each component was sufficient for screening or classification of whole kernel barley, except for beta-glucan. The higher resolution Fourier transform instrument gave better results than the lower resolution instrument for starch and beta-glucan analysis. The starch model was most improved by the increased resolution. There was no advantage of using a higher resolution instrument over a lower resolution instrument for other components. Most of the components were best predicted using first-derivative processing, except for beta-glucan, where second-derivative processing was more informative and precise.

Bioethanol production from barley hull using SAA (soaking in aqueous ammonia) pretreatment.

Barley hull, a lignocellulosic biomass, was pretreated using aqueous ammonia, to be converted into ethanol. Barley hull was soaked in 15 and 30 wt.% aqueous ammonia at 30, 60, and 75 degrees C for between 12 h and 11 weeks. This pretreatment method has been known as "soaking in aqueous ammonia" (SAA). Among the tested conditions, the best pretreatment conditions observed were 75 degrees C, 48 h, 15 wt.% aqueous ammonia and 1:12 of solid:liquid ratio resulting in saccharification yields of 83% for glucan and 63% for xylan with 15 FPU/g-glucan enzyme loading. Pretreatment using 15 wt.% ammonia for 24-72 h at 75 degrees C removed 50-66% of the original lignin from the solids while it retained 65-76% of the xylan without any glucan loss. Addition of xylanase along with cellulase resulted in synergetic effect on ethanol production in SSCF (simultaneous saccharification and co-fermentation) using SAA-treated barley hull and recombinant E. coli (KO11). With 3% w/v glucan loading and 4 mL of xylanase enzyme loadings, the SSCF of the SAA treated barley hull resulted 24.1g/L ethanol concentration at 15 FPU cellulase/g-glucan loading, which corresponds to 89.4% of the maximum theoretical yield based on glucan and xylan. SEM results indicated that SAA treatment increased surface area and the pore size. It is postulated that these physical changes enhance the enzymatic digestibility in the SAA treated barley hull.