Efficient production of 1,2,4-butanetriol from corn cob hydrolysate by metabolically engineered Escherichia coli.

Corn cob is a major waste mass-produced in corn agriculture. Corn cob hydrolysate containing xylose, arabinose, and glucose is the hydrolysis product of corn cob. Herein, a recombinant Escherichia coli strain BT-10 was constructed to transform corn cob hydrolysate into 1,2,4-butanetriol, a platform substance with diversified applications. To eliminate catabolite repression and enhance NADPH supply for alcohol dehydrogenase YqhD catalyzed 1,2,4-butanetriol generation, ptsG encoding glucose transporter EIICBGlc and pgi encoding phosphoglucose isomerase were deleted. With four heterologous enzymes including xylose dehydrogenase, xylonolactonase, xylonate dehydratase, α-ketoacid decarboxylase and endogenous YqhD, E. coli BT-10 can produce 36.63 g/L 1,2,4-butanetriol with a productivity of 1.14 g/[L·h] using xylose as substrate. When corn cob hydrolysate was used as the substrate, 43.4 g/L 1,2,4-butanetriol was generated with a productivity of 1.09 g/[L·h] and a yield of 0.9 mol/mol. With its desirable characteristics, E. coli BT-10 is a promising strain for commercial 1,2,4-butanetriol production.

High-level production of Aspergillus niger prolyl endopeptidase from agricultural residue and its application in beer brewing.

BACKGROUND: Prolyl endopeptidase from Aspergillus niger (AN-PEP) is a prominent serine proteinase with various potential applications in the food and pharmaceutical industries. However, the availability of efficient and low-cost AN-PEP remains a challenge owing to its low yield and high fermentation cost. RESULTS: Here, AN-PEP was recombinantly expressed in Trichoderma reesei (rAN-PEP) under the control of the cbh1 promoter and its secretion signal. After 4 days of shaking flask cultivation with the model cellulose Avicel PH101 as the sole carbon source, the extracellular prolyl endopeptidase activity reached up to 16.148 U/mL, which is the highest titer reported to date and the secretion of the enzyme is faster in T. reesei than in other eukaryotic expression systems including A. niger and Komagataella phaffii. Most importantly, when cultivated on the low-cost agricultural residue corn cob, the recombinant strain was found to secret a remarkable amount of rAN-PEP (37.125 U/mL) that is twice the activity under the pure cellulose condition. Furthermore, treatment with rAN-PEP during beer brewing lowered the content of gluten below the ELISA kit detection limit (< 10 mg/kg) and thereby, reduced turbidity, which would be beneficial for improving the non-biological stability of beer. CONCLUSION: Our research provides a promising approach for industrial production of AN-PEP and other enzymes (proteins) from renewable lignocellulosic biomass, which provides a new idea with relevant researchers for the utilization of agricultural residues.

Denitrification efficiency, microbial communities and metabolic mechanisms of corn cob hydrolysate as denitrifying carbon source.

In this study, the denitrification efficacy of corn cob hydrolysate (CCH) was compared and analyzed with that of glucose and acetate to determine its feasibility as an additional carbon source, and its metabolic mechanism as a denitrification carbon source was investigated in depth. By constructing a denitrification reactor, it was found that the TN removal rate exceeded 97% and the effluent COD remained below 70 mg/L during the stable operation with CCH as the carbon source, and the denitrification effect was comparable to that of the glucose stage (GS) and the acetate stage (AS). The analysis of the microbial community showed that the dominant phylum was Proteobacteria and Bacteroidota, where the abundance of Bacteroidota in the hydrolysate stage (HS) (24.37%) was significantly higher than that of GS (4.89%) and AS (11.93%). And the analysis at the genus level showed the presence of a large number of genera of organic matter hydrolysis and acid production in HS that were almost absent in other stages, such as Paludibacter (12.83%), Gracilibacteria (4.27%), f__Prolixibacteraceae_Unclassified (2.94%). In addition, the higher fatty acid metabolism and lower sugar metabolism of HS during carbon metabolism were similar to the ratio of AS, suggesting that CCH was mainly fermented to acids and then involved in the tricarboxylic acid (TCA) cycle. During nitrogen metabolism, the high relative abundance of narG, nirS, and nosZ ensured the denitrification process. The results of this study were expected to provide a theoretical basis and data support for promoting denitrification from novel carbon sources.

Structural Characterization, In Vitro Digestion Property, and Biological Activity of Sweet Corn Cob Polysaccharide Iron (III) Complexes.

This study aimed to enhance the utilization value of sweet corn cob, an agricultural cereal byproduct. Sweet corn cob polysaccharide-ron (III) complexes were prepared at four different temperatures (40 °C, 50 °C, 60 °C, and 70 °C). It was demonstrated that the complexes prepared at different temperatures were successfully bound to iron (III), and there was no significant difference in chemical composition; and SCCP-Fe-C demonstrated the highest iron content. The structural characterization suggested that sweet corn cob polysaccharide (SCCP) formed stable ß-FeOOH iron nuclei with -OH and -OOH. All the four complexes' thermal stability was enhanced, especially in SCCP-Fe-C. In vitro iron (III) release experiments revealed that all four complexes were rapidly released and acted as iron (III) supplements. Moreover, in vitro antioxidant, α-glucosidase, and α-amylase inhibition studies revealed that the biological activities of all four complexes were enhanced compared with those of SCCP. SCCP-Fe-B and SCCP-Fe-C exhibited the highest in vitro antioxidant, α-glucosidase, and α-amylase inhibition abilities. This study will suggest using sweet corn cobs, a natural agricultural cereal byproduct, in functional foods. Furthermore, we proposed that the complexes prepared from agricultural byproducts can be used as a potential iron supplement.

Enhanced biodegradation of oil-contaminated soil oil in shale gas exploitation by biochar immobilization.

The enhanced biodegradation of oil-contaminated soil by fixing microorganisms with corn cob biochar was investigated. It was found that the components of oil in the test soil were mainly straight-chain alkanes and branched alkanes. When using corn cob biochar as a carrier to immobilize microorganisms, the best particle size of corn cob biochar as an immobilization carrier was 0.08 mm, and the best immobilization time was 18 h. SEM analysis confirmed that the microorganisms were immobilized on the corn cob biochar. Immobilized microorganisms exhibited high biodegradability under stress to high concentrations of petroleum pollutants, heavy metals, and organic pollutants. Infrared spectroscopy analysis showed that oxygen-containing groups such as hydroxyl, carboxyl, and methoxy on the surface of biochar were involved in the complexation of heavy metals. The mechanism of immobilization promoted microbial degradation of oil contamination was explained by gas chromatography mass. First, alkanes and aromatics were adsorbed by corn cob biochar and passed to immobilized microorganisms to promote their degradation. Their bioavailability increased, especially for aromatics. Second, biochar provided a more suitable environment for microorganisms to degrade. Third, the conversion of ketones to acids was accelerated during the biodegradation of alkanes, and the biodegradation of alkanes was accelerated by immobilization. The biodegradable efficiency of oil by immobilized microorganisms in soil was 70.10% within 60 days, 28.80% higher than that of free microorganisms. The degradation of immobilized microorganisms was highly correlated with the activities of catalase, urease, and polyphenol oxidase.

Corn Cob as a Green Support for Laccase Immobilization-Application on Decolorization of Remazol Brilliant Blue R.

The high demand for food and energy imposed by the increased life expectancy of the population has driven agricultural activity, which is reflected in the larger quantities of agro-industrial waste generated, and requires new forms of use. Brazil has the greatest biodiversity in the world, where corn is one of the main agricultural genres, and where over 40% of the waste generated is from cobs without an efficient destination. With the aim of the valorization of these residues, we proposed to study the immobilization of laccase from Aspergillus spp. (LAsp) in residual corn cob and its application in the degradation of Remazol Brilliant Blue R (RBBR) dye. The highest yields in immobilized protein (75%) and residual activity (40%) were obtained at pH 7.0 and an enzyme concentration of 0.1 g.mL-1, whose expressed enzyme activity was 1854 U.kg-1. At a temperature of 60 °C, more than 90% of the initial activity present in the immobilized biocatalyst was maintained. The immobilized enzyme showed higher efficiency in the degradation (64%) of RBBR dye in 48 h, with improvement in the process in 72 h (75%). The new biocatalyst showed operational efficiency during three cycles, and a higher degradation rate than the free enzyme, making it a competitive biocatalyst and amenable to industrial applications.

Initial carbon release characteristics, mechanisms and denitrification performance of a novel slow release carbon source.

External carbon source addition is one of the effective methods for the treatment of wastewater with low carbon to nitrogen ratio (C/N). Compared with fast-release liquid carbon sources, slow-release solid carbon sources are more suitable for the denitrification process. A novel slow-release solid carbon source (corncob-polyvinyl alcohol sodium alginate- poly-caprolactone, i.e. CPSP) was prepared using corn cob (CC) and poly-caprolactone with polyvinyl alcohol sodium alginate as hybrid scaffold. The physical properties and carbon release characteristics of CPSP and three other carbon sources were compared. CPSP had stable framework and good carbon release performance, which followed the second order release equation. The formic acid, acetic acid, propionic acid and butyric acid released from CPSP accounted for 8.27% ± 1.66 %, 56.48% ± 3.71 %, 18.46% ± 2.69% and 16.79% ± 3.02% of the total released acids respectively. The start-up period of CPSP was shorter than that of the other carbon sources in denitrification experiment, and no COD pollution was observed in the start-up phase (25-72 h) and stable phase (73-240 hr). The composition and structure of the dissolved organic compounds released by CPSP and other carbon sources were analyzed by UV-Vis absorption spectroscopy and three-dimensional fluorescence spectroscopy, which indicated that CPSP was more suitable for denitrification than the other studied carbon sources.

Efficient biological pretreatment and bioconversion of corn cob by the sequential application of a Bacillus firmus K-1 cellulase-free xylanolytic enzyme and commercial cellulases.

We used agricultural residue, corn cob, with biorefinery and bioeconomy concepts. At short-time cultivation in corn cob (12 h), Bacillus firmus K-1 produced cellulase-free xylanolytic enzyme, with xylooligosaccharides (XOSs), X5 and X6, as the main products, which can be used in a variety of applications. The xylanolytic enzyme produced from B. firmus K-1 effectively degraded xylan in corn cob, which was examined by chemical composition, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). After cultivation, the xylan contained in the corn cob residue was decreased (as biological pretreatment), causing morphological and structural changes, including creating porosity and increasing the surface area and the exposure of cellulose of pretreated corn cob. These results lead to an improvement of cellulose access by cellulases. Commercially available cellulases, Accellerase® 1500 and Cellic® CTec2, yielded significantly higher glucose concentrations from pretreated corn cob compared to untreated corn cob. After saccharification, the lignin-rich corn cob residue can be used as a raw material for other purposes. Moreover, the B. firmus cells, with a low risk to human health, can be used in some applications. This study presents an efficient method for producing high-value-added products from agricultural residue (corn cob) through biological processes which are environmentally friendly and economically viable. KEY POINTS: • High-value-added products were efficiently produced from corn cob by B. firmus K-1. • After biological pretreatment by B. firmus K-1, cellulase can better reach cellulose. • XOSs and cellulose-derived glucose were the main products from corn cob.

Plant-derived silica nanoparticles and composites for biosensors, bioimaging, drug delivery and supercapacitors: a review.

Silica nanoparticles have rapidly found applications in medicine, supercapacitors, batteries, optical fibers and concrete materials, because silica nanoparticles have tunable physical, chemical, optical and mechanical properties. In most applications, high-purity silica comes from synthetic organic precursors, yet this approach could be costly, polluting and non-biocompatible. Alternatively, natural silica sources from biomass are often cheap and abundant, yet they contain impurities. Silica can be extracted from corn cob, coffee husk, rice husk, sugarcane bagasse and wheat husk wastes, which are often disposed of in rivers, lands and ponds. These wastes can be used to prepare homogenous silica nanoparticles. Here we review properties, preparation and applications of silica nanoparticles. Preparation includes chemical and biomass methods. Applications include biosensors, bioimaging, drug delivery and supercapacitors. In particular, to fight the COVID-19 pandemic, recent research has shown that silver nanocluster/silica deposited on a mask reduces SARS-Cov-2 infectivity to zero.

Co-culturing corncob-immobilized yeasts on orange peels for the production of pectinase.

OBJECTIVE: Pectinase is an industrially important enzyme which is employed in an array of commercial processes; cost of production, however, impedes its application. The main objective of this study was to design a two-layered strategy for the reduction of production cost, firstly by using a yeast co-culture in an immobilized form on an agricultural waste matrix, corncob (CB), secondly by utilizing orange peels (OP) as substrate. RESULTS: Two yeast strains, Saccaromyces cerevisiae MK-157 and Geotrichum candidum AA15 were cultivated as mono-, as well as, co-culture after immobilization on CB and pectinase production was monitored. Initial experiments revealed that co-culture is beneficial to get sustainable product in subsequent 2nd and 3rd production cycles. The factors affecting pectinase production in consecutive three production cycles were studied by employing Plackett-Burman design and the significant factors were optimized through Box-Behnken design. Under optimized conditions, 17.89 IU mL-1 of pectinase was obtained. Scanning electron micrographs presented damaged immobilized yeast cells on CB after the 3rd production cycle. CONCLUSION: The pectinase production was improved substantially by using immobilized co-culture and hence the strategy was found effective at lab scale. Since, pectinase is applied in orange juice clarification, therefore, the study can be extended to move forward towards circular economy.

Mixing of Prosopis africana pods and corn cob exerts contrasting effects on the production and quality of Bacillus thuringiensis crude endoglucanase.

Recently, attention has shifted to the use of mixed lignocellulosic substrates for the production of cellulolytic enzymes. However, researchers have focused mainly on achieving increased enzyme yields while neglecting other properties of the enzymes when using such mixtures. In this first-ever report of the application of Prosopis africana pod (PAP) in cellulase production, we investigated the effect of its combination with corn cob (CC), as an inducing carbon source, on the amounts and quality of crude endoglucanase produced by Bacillus thuringiensis SS12. The organism was grown on PAP, CC or their 1:1% w/w mixture (MS) and the crude endoglucanases produced were tested for activity, hydrolytic efficiency, and thermostability. PAP supported the highest enzyme activity (0.138 U/mL) and its endoglucanase was the most effective in hydrolyzing CMC and filter paper while CC-derived endoglucanase was the best for hydrolysis of alkali-pretreated CC. Enzyme activity of MS-derived endoglucanase (0.110 U/mL) was intermediate to that of PAP and CC (0.091 U/mL) and was the most stable at elevated temperatures (70 and 80 °C). It also liberated the least amount of reducing sugars from all tested substrates. Combination of both the substrates, thus, favored enzyme production and thermostability but was detrimental to hydrolytic efficiency.

Optimization of enzyme-assisted extraction of ferulic acid from sweet corn cob by response surface methodology.

BACKGROUND: Sweet corn cob (SCC), an agricultural by-product of the corn-processing industry, contains more than 80% insoluble bound ferulic acid (FA). Extraction of these bound phenolics can be achieved through chemical or enzymatic hydrolysis; however, the shift towards greener chemistry has raised awareness about the use of enzymatic hydrolysis. In the present study, the ability of ferulic acid esterase (FAE) and xylanase (XY) to catalyze the hydrolysis of FA from SCC was investigated. Response surface methodology (RSM), based on a five-level, four-factor central composite rotatable design (CCRD), was used to establish the optimum conditions for enzymatic hydrolysis of FA from SCC. Sweet corn cob was treated with a combination of FAE and XY at various concentrations (FAE: 0.00 to 0.04 U/g; XY: 0.00 to 18 093.5 U/g), temperatures (45 to 65 °C), and pH levels (pH 4.5 to 6.5). RESULTS: The optimum extraction conditions predicted by the model were: FAE concentration of 0.02 U/g, XY concentration of 3475.3 U/g, extraction pH of 4.5, and an extraction temperature of 45 °C. CONCLUSION: Under these conditions, the experimental yield of FA was 1.69 ± 0.02 g kg-1 of SCC, which is in agreement with the value predicted by the model. © 2019 Society of Chemical Industry.

Analysis of pelletizing from corn cob waste.

In recent years, biomass market has constantly increased. Pellet industry has started looking for new products with the potential to be used as biofuels. Among them are agricultural wastes, such as corn cob waste, which presents some characteristics that make its direct use in industrial facilities possible. However, these properties are not enough for its use in domestic stoves and boilers, where higher quality of fuel is needed. For this reason, densification is used. In the present research work a technical and energy analysis of corn cob waste pelletizing was carried out in a semi-industrial pelletizer. Some relationships between variables, such as moisture, bulk density and mechanical durability, were analyzed, as well as their influence on energy use and final productivity. The results were satisfactory, as the pellets manufactured fulfilled with most specifications that were consulted, with higher values than those recorded for similar kinds of pellets. Concerning the energy study, the increase in production justified a higher energy consumption of the process in order to get a higher productivity ratio.

UPLC-ESI-QTOF-MS²-Based Identification and Antioxidant Activity Assessment of Phenolic Compounds from Red Corn Cob (Zea mays L.).

In this study, the extraction of phenolic antioxidants from red corn cob was carried out using ultrasound-assisted extraction (UAE). The solid:liquid ratio and extraction time were evaluated when obtaining these bioactive compounds. The total phenolic contents were evaluated using the Folin Ciocalteu method, while the antioxidant activity was measured by ABTS•+ and DPPH• assays. The amount of phenolic compounds ranged from 215.17 ± 33.49 to 527.33 ± 103.79 GAE mg/100 g and, overall, high solid:liquid ratios and time periods release more phenolic compounds. Moreover, the red corn cob extracts showed higher radical scavenging capacity according to the results obtained using the ABTS•+ technique compared to the DPPH• test. The coupling of liquid chromatography and mass spectrometry assay allowed the determination of 11 phenolic compounds, including phenolic acids and flavonoids. Thus, our results demonstrated for the first time the potential of red corn cob as a source of bioactive compounds, which might be included in food and pharmacological preparations.

Critical factors affecting ethanol production by immobilized Pichia stipitis using corn cob hemicellulosic hydrolysate.

Fermentation of xylose from hydrolysate of acid-treated corn cob by Pichia stipitis is inhibited by acetic acid and lignin derivatives. In the present study, we have designed and implemented an immobilized cell culture for xylose to ethanol conversion from acid-treated corn cob hydrolysate without the removal of fermentation inhibitors. In this study, cultivations of suspended and immobilized Pichia were compared in terms of ethanol yield and productivity to investigate whether the cell immobilization could improve resistance to inhibitors. Cell immobilization clearly favored the fermentative metabolism in nondetoxified corn cob hydrolysate leading to an improvement of twofold ethanol productivity as compared to that achieved with suspension culture. Calcium alginate as an immobilization matrix was selected to immobilize Pichia cells. Concentrations of sodium alginate, calcium chloride, and fermentor agitation speed were optimized for ethanol production using statistical method. Statistical analysis showed that agitation speed had maximum influence on ethanol production by immobilized Pichia cells. In comparison to suspension culture, immobilization had a positive impact on the fermentative metabolism of Pichia, improving the ethanol yield from 0.40 to 0.43 g/g and productivity from 0.31 to 0.51 g/L/h for acid-treated corn cob hydrolysate.

Xylitol production by genetically modified industrial strain of Saccharomyces cerevisiae using glycerol as co-substrate.

Xylitol is commercially used in chewing gum and dental care products as a low calorie sweetener having medicinal properties. Industrial yeast strain of S. cerevisiae was genetically modified to overexpress an endogenous aldose reductase gene GRE3 and a xylose transporter gene SUT1 for the production of xylitol. The recombinant strain (XP-RTK) carried the expression cassettes of both the genes and the G418 resistance marker cassette KanMX integrated into the genome of S. cerevisiae. Short segments from the 5' and 3' delta regions of the Ty1 retrotransposons were used as homology regions for integration of the cassettes. Xylitol production by the industrial recombinant strain was evaluated using hemicellulosic hydrolysate of the corn cob with glucose as the cosubstrate. The recombinant strain XP-RTK showed significantly higher xylitol productivity (212 mg L-1 h-1) over the control strain XP (81 mg L-1 h-1). Glucose was successfully replaced by glycerol as a co-substrate for xylitol production by S. cerevisiae. Strain XP-RTK showed the highest xylitol productivity of 318.6 mg L-1 h-1 and titre of 47 g L-1 of xylitol at 12 g L-1 initial DCW using glycerol as cosubstrate. The amount of glycerol consumed per amount of xylitol produced (0.47 mol mol-1) was significantly lower than glucose (23.7 mol mol-1). Fermentation strategies such as cell recycle and use of the industrial nitrogen sources were demonstrated using hemicellulosic hydrolysate for xylitol production.

Evaluation of different agricultural wastes for the production of fruiting bodies and bioactive compounds by medicinal mushroom Cordyceps militaris.

BACKGROUND: In commercial production of Cordyceps militaris (a famous Chinese medicine), cereal grains are usually utilized as cultivation substrates. This study aimed to evaluate the efficiency of agricultural wastes as substitute materials in the low-cost production of C. militaris. Cottonseed shells (CS), corn cob particles (CCP), Italian poplar sawdusts (IPS) and substrates spent by Flammulina velutipes (SS) were employed to cultivate C. militaris, using rice medium as control. RESULTS: CS and CCP were suitable for fruit body formation of C. militaris, with yields of 22 and 20 g per bottle respectively. Fruit bodies grown on CCP showed the highest levels of cordycepin and adenosine, up to 9.45 and 5.86 mg g-1 respectively. The content of d-mannitol in fruit bodies obtained on CS was 120 mg g-1 (80% of the control group), followed by that on CCP, 100 mg g-1 . Fruit bodies cultivated on CCP displayed a high crude polysaccharide level of 26.9 mg g-1 , which was the closest to that of the control group (34.5 mg g-1 ). CONCLUSION: CS and CCP are effective substrates for the production of fruit bodies and bioactive compounds by C. militaris. This study provides a new approach to decreasing the cost of C. militaris cultivation and dealing with these agricultural wastes. © 2016 Society of Chemical Industry.

A steady state model of agricultural waste pyrolysis: A mini review.

Agricultural waste is one of the main renewable energy resources available, especially in an agricultural country such as Serbia. Pyrolysis has already been considered as an attractive alternative for disposal of agricultural waste, since the technique can convert this special biomass resource into granular charcoal, non-condensable gases and pyrolysis oils, which could furnish profitable energy and chemical products owing to their high calorific value. In this regard, the development of thermochemical processes requires a good understanding of pyrolysis mechanisms. Experimental and some literature data on the pyrolysis characteristics of corn cob and several other agricultural residues under inert atmosphere were structured and analysed in order to obtain conversion behaviour patterns of agricultural residues during pyrolysis within the temperature range from 300 °C to 1000 °C. Based on experimental and literature data analysis, empirical relationships were derived, including relations between the temperature of the process and yields of charcoal, tar and gas (CO2, CO, H2 and CH4). An analytical semi-empirical model was then used as a tool to analyse the general trends of biomass pyrolysis. Although this semi-empirical model needs further refinement before application to all types of biomass, its prediction capability was in good agreement with results obtained by the literature review. The compact representation could be used in other applications, to conveniently extrapolate and interpolate these results to other temperatures and biomass types.

Characterization of the carbonaceous materials obtained from different agro-industrial wastes.

This paper reports the preparation and characterization of carbonaceous materials obtained from three types of vegetable wastes provided by agricultural industries. Soft carbonization (280°C) and H3PO4-activation procedures were used to convert the agricultural wastes to carbon powders with high adsorbent capacities. This process is excellent for eliminating and exploiting the huge masses (many tons) of vegetable residues remaining after each harvest every year in several Colombian agro-industries. The powders were characterized by X-ray diffraction (XRD), IR spectroscopy, scanning electron microscopy (SEM), and N2-adsorption isotherms. XRD and IR verified the formation of carbons, and SEM showed small particles (20-500 µm) with characteristic morphology for each type of residue used and abundant cavities of different sizes. The N2-adsorption analyses showed that the carbons had high adsorption capacities with important surface area values and large pore volumes. The use of the activated carbonaceous materials as adsorbent of azo dyes (allura red and sunset yellow) from aqueous solutions was evaluated. The results showed a good adsorption capacity indicating the potentiality of these materials as pollutant adsorbents in food industry wastewaters. These results indicate that these powders can be used as potential adsorbents for different gaseous or liquid pollutants.

Aspergillus labruscus ITAL 22.223 xylanase - immobilization and application for the obtainment of corncob xylan targeting xylitol production.

Corncob is an agro-residue rich in lignocellulosic material that can be used for the xylitol production, through its enzymatic conversion obtaining fermentable sugars and their subsequent fermentation. In light of the above, this study targeted the immobilization of Aspergillus labruscus xylanase and the use of the derivative to hydrolyze the corncob xylan for the obtainment of xylose, and its subsequent use for the production of xylitol. The extracellular xylanase was immobilized using different supports (sodium alginate, DEAE-Cellulose, DEAE-Sephadex and CM-Sephadex). Among all supports used, the best results were obtained with the DEAE-Cellulose derivative showing an efficiency of immobilization of 97-99%, yield of 93-95% and recovered activity of 81-100%. The sodium alginate derivative showed 3 cycles of reuse, with drop in activity of about 65% in the 3rd cycle using both CaCl2 and MnCl2 as crosslinkers. The best enzymatic activity for the DEAE-Cellulose derivative was observed at 55ºC and pH 5.0. This derivative presented reuse of 10 cycles using commercial xylan as substrate, and 4 cycles using corncob xylan. This derivative was used in an enzymatic reactor to hydrolyze corncob xylan, obtaining 2.7 mg/mL of xylose after 48 h of operation under optimal condition of temperature and pH. The xylose obtained from the corncob was fermented by Candida tropicalis for 96 h with consumption of 60%. The HPLC analyses indicated a production of 1.02 mg/mL of xylitol with 48 h of fermentation. In conclusion, this is the first report on the immobilization of the A. labrucus xylanase as an alternative for the obtainment of xylose from corncob xylan, and the subsequent production of xylitol.