Corncob Hemicellulose Research Articles

Integrated production of xylose and docosahexaenoic acid from hemicellulose and cellulose in corncob

Exploring efficient and comprehensive utilization of agricultural waste to produce high value-added products has been global research hotspot. In this study, a novel process for integrated production of xylose and docosahexaenoic acid (DHA) from hemicellulose and cellulose in corncob was developed. Corncob was treated with dilute H2SO4 at 121 °C for 1 h and xylose was readily produced with a recovery yield of 79.35 %. The corncob residue was then subject to alkali pretreatment under optimized conditions of 0.1 g NaOH/g dry solid, 60 °C for 2 h, and the contents of cellulose, hemicellulose, and lignin in the resulting residue were 87.49 %, 7.58 % and 2.31 %, respectively. The cellulose in the residue was easily hydrolyzed by cellulase, yielding 74.87 g/L glucose with hydrolysis efficiency of 77.02 %. Remarkably, the corncob residue hydrolysate supported cell growth and DHA production in Schizochytrium sp. ATCC 20888 well, and the maximum biomass of 32.71 g/L and DHA yield of 4.63 g/L were obtained, with DHA percentage in total fatty acids of 36.89 %. This study demonstrates that the corncob residue generated during xylose production, rich in cellulose, can be effectively utilized for DHA production by Schizochytrium sp., offering a cost-effective and sustainable alternative to pure glucose.

WITHDRAWN: Component Analysis of Corncob after Hydrothermal Treatment

Hydrothermal pretreatment is a green pretreatment technology, which can effectively promote the degradation of biomass without adding any chemical reagent. In this study, hydrothermal pretreatment on improving digestibility of corncobs was investigated and the effect of hydrothermal pretreatment on changes of structure of the corncob lignocellulose was investigated. The composition and amounts of sugar content in hydrolysate and enzymatic hydrolysate were determined. Hydrothermal treatment destroyed the lignocellulose structure of corncob and caused different degrees of degradation. With the increasing temperature of hydrothermal treatment, the degradation of cellulose, hemicellulose and lignin in corncob was detected with increasing the content of reducing sugars in hydrolysate. The hydrolysate of corncob treated by hydrothermal treatment at 190 ℃ for 60min mainly included glucose, xylobiose, xylotriose and xylotetraose. The content of glucose, xylobiose, xylotriose and xylotetraose in the hydrolysate of hydrothermal treatment corncob was at level of 0.001mg·g-1, 16.740mg·g-1, 4.306mg·g-1 and 3.164mg·g-1 respectively. The yield of glucose, xylobiose, xylotriose and xylotetraose in enzymatic hydrolysate were 4.771mg·g-1, 64.437mg·g-1, 6.853mg·g-1 and 1.835mg·g-1, respectively. The understanding will help to improve the conversion and utilization of corncob as an agriculture residue.

Component Analysis of Corncob After Hydrothermal Treatment

Hydrothermal pretreatment is a green pretreatment technology, which can effectively promote the degradation of biomass without adding any chemical reagent. In this study, hydrothermal pretreatment on improving digestibility of corncobs was investigated and the effect of hydrothermal pretreatment on changes of structure of the corncob lignocellulose was investigated. The composition and amounts of sugar content in hydrolysate and enzymatic hydrolysate were determined. Hydrothermal treatment destroyed the lignocellulose structure of corncob and caused different degrees of degradation. With the increasing temperature of hydrothermal treatment, the degradation of cellulose, hemicellulose and lignin in corncob was detected with increasing the content of reducing sugars in hydrolysate. The hydrolysate of corncob treated by hydrothermal treatment at 190 °C for 60 min mainly included glucose, xylobiose, xylotriose and xylotetraose. The content of glucose, xylobiose, xylotriose and xylotetraose in the hydrolysate of hydrothermal treatment corncob was at level of 0.001 mg • g−1, 16.740 mg • g−1, 4.306 mg • g−1 and 3.164 mg • g−1 respectively. The yield of glucose, xylobiose, xylotriose and xylotetraose in enzymatic hydrolysate were 4.771 mg • g−1, 64.437 mg • g−1, 6.853 mg • g−1 and 1.835 mg • g−1, respectively. The understanding will help to improve the conversion and utilization of corncob as an agriculture residue.

Bioconversion of cellulose and hemicellulose in corn cob into L-lactic acid and xylo-oligosaccharides

With the banning of antibiotic chemical feed additives, multi-functional bioactive feed additives have been extensively sought after by the feed industry. In this study, low-cost and renewable corn cobs were treated with liquid hot water and converted into bioactive xylo-oligosaccharides and L-lactic acid after enzymatic hydrolysis, strain activation, and fermentation under mild conditions, which achieved a full utilization of cellulose and hemicellulose in corn cobs. Simultaneous saccharification fermentation after strain activation with enzymatic hydrolysate delivered the highest conversion rate of glucose to L-lactic acid (93.00 %) and yielded 17.38 g/L L-lactic acid and 2.68 g/L xylo-oligosaccharides. On this basis, batch-feeding fermentation resulted in a 78.03 % conversion rate of glucose to L-lactic acid, 18.99 g/L L-lactic acid, and 2.84 g/L xylo-oligosaccharides. This work not only provided a green and clean bioconversion strategy to produce multi-functional feed additives but can also boost the full utilization of renewable and cheap biomass resources.

In-situ detoxification and enhanced oxygen mass transfer for C5 sugar acid production from corncob hemicellulose hydrolysates using activated carbon particles

In this work, an easily implemented and cost-effective activated carbon (AC) enhanced technique was proposed for C5 sugar acid production from corncob hemicellulose hydrolysates. The optimum AC detoxification conditions were obtained by response surface methodology, and the fermentation kinetics behaviors were comparatively evaluated using two fermentation modes: separate detoxification and fermentation (SDF) and in-situ detoxification and fermentation (In-situDF). An investigation of the AC function demonstrates it offers synchronous detoxification and oxygen transfer enhancement, with a final increase of XA fermentation yield and productivity. This study shows a potential of detoxification and oxygen transfer enhancement in one-pot in C5 sugar acid production, which may smooth the way for commercial utilization of C5 sugars from lignocellulosic biomass in the future.

Simultaneous saccharification of hemicellulose and cellulose of corncob in a one-pot system using catalysis of carbon based solid acid from lignosulfonate.

The drive towards sustainable chemistry has inspired the development of active solid acids as catalysts and ionic liquids as solvents for an efficient release of sugars from lignocellulosic biomass for future biorefinery practices. Carbon-based solid acid (SI-C-S-H2O2) prepared from sodium lignosulfonate, a waste of the paper industry, was used with water or ionic liquid to hydrolyze corncob in this study. The effects of various reaction parameters were investigated in different solvent systems. The highest xylose yield of 83.4% and hemicellulose removal rate of 90.6% were obtained in an aqueous system at 130 °C for 14 h. After the pretreatment, cellulase was used for the hydrolysis of residue and the enzymatic digestibility of 92.6% was obtained. Following these two hydrolysis steps in the aqueous systems, the highest yield of total reducing sugar (TRS) was obtained at 88.1%. Further, one-step depolymerization and saccharification of corncob hemicellulose and cellulose to reducing sugars in an IL-water system catalyzed by SI-C-S-H2O2 was conducted at 130 °C for 10 h, with a high TRS yield of 75.1% obtained directly. After recycling five times, the solid acid catalyst still showed a high catalytic activity for sugar yield in different systems, providing a green and effective method for lignocellulose degradation.

Process simulation and economic and environmental evaluation of a corncob-based biorefinery system

A new biorefinery system of producing bioethanol, xylose, electricity and steam from corncob was analyzed by a systematic methodology of process simulation, pinch analysis, economic analysis and life cycle assessment (LCA). The biorefinery system processing 875 kt/a corncob and operating 8400 h/a was first simulated in Aspen Plus. Through process integration in Aspen Energy Analyzer, the biorefinery system reduced 36.8% of cooling utilities and 60.6% of heating utilities, achieved by the installation of 10 heat exchangers. The yield of bioethanol, 194.2 L/t dry corncob, was lower than other biorefineries because hemicellulose in corncob was employed to produce high-valued xylose. However, the production cost, 0.50 $/L bioethanol, made it quite competitive due to the sale price of xylose being more than two times higher than bioethanol. Lastly, the new biorefinery system was evaluated by environmental performance of using LCA method in SimaPro software. Two other biorefinery systems involved with same feedstock and capacity, but different conversion routes were conducted as base cases. The results showed that pretreatment, bioethanol production and wastewater treatment contributed most to the fossil fuels depletion (FDP) and global warming potential (GWP) impacts. The new biorefinery system showed significantly better performance compared with other cases, FDP 25.5 MJ/t dry corncob (0.05 MJ/MJ bioethanol) and GWP 0.45 t CO2 eq/t dry corncob (0.11 kg CO2 eq/MJ bioethanol).

Particle size influence on the composition of sugars in corncob hemicellulose hydrolysate for xylose fermentation by Meyerozyma caribbica

The xylitol production was performed with acidophilic Meyerozyma caribbica. The particle size of 0.02 ± 0.01 to 0.1 ± 0.05 mm was rich in glucose (12.0 ± 0.5 g/L), whereas 0.5 ± 0.25 to 2.0 ± 0.5 mm had a high content of xylose (8.0 ± 0.5 g/L). The xylitol production in the synthetic, non-detoxified and detoxified hydrolysate media was studied (50 ± 0.5 g/L) using 10% v/v non - induced cells of M. caribbica for 120 h. At the end of fermentation with the specific growth rate of 0.056 ± 0.01 (μ), xylitol yields of 45.00 ± 1.00%, 10.00 ± 1.00% and 54.00 ± 1.00% were obtained. The detoxification of the hydrolysate prepared using an identified corncob particle size of 0.5 ± 0.25 to 2.0 ± 0.5 mm could be used as the prospective pretreatment process for ecofriendly and industrial scale production of xylitol with M. caribbica.

Selective degradation and oxidation of hemicellulose in corncob to oligosaccharides: From biomass into masking agent for sustainable leather tanning

Chrome-free metal tanning agent has been considered as eco-friendly in the leather industry. However, extensive crosslinking reactions of metal species on the leather surface restrain their uniform penetration into the hierarchical nanoscale leather matrix. Thus, masking agents with appropriate coordination ability are needed. Herein, the selective degradation of hemicellulose in corncob was achieved with 92.5% of conversion in an AlCl3–H2O system, obtaining oligosaccharides masking agent with high purity and leaving cellulose and lignin in the solid residue for other valuable use. Subsequently, H2O2 oxidation was performed to introduce –CHO/–COOH into oligosaccharides and reduce their molecular weights, thereby enhancing coordination ability and reducing ligand dimension. The post-oxidized reaction fluids together with additional Zr species were subjected to leather tanning, in which the oligosaccharides could coordinate with Al/Zr species and promote the penetration of metal species into the leather matrix. By controlling the hemicellulose degradation and oligosaccharide oxidation, an appropriate concentration of oligosaccharides with proper –CHO/–COOH contents allowed the efficient masking effect of the oligosaccharides. As a result, a uniform distribution of Al/Zr species was observed on the cross section, and 83.5 °C of shrinkage temperature was obtained for the chrome-free tanned leather.

Selective conversion of corncob hemicellulose to xylose via hydrothermal treatment with Fe2(SO4)3 and NaCl

Selective conversion of corncob hemicellulose to xylose via hydrothermal treatment with Fe2(SO4)3 and NaCl

On the development of chrome-free tanning agents: an advanced Trojan horse strategy using ‘Al–Zr-oligosaccharides’ produced by the depolymerization and oxidation of biomass

Hemicellulose in corncob was simultaneously degraded and oxidized into oligosaccharides, which served as a masking agent for leather tanning.

Hydrolysis of Corncob Hemicellulose by Solid Acid Sulfated Zirconia and Its Evaluation in Xylitol Production

Corncob is an abundant agricultural residue containing high content of hemicellulose. In this paper, the hemicellulosic hydrolysate was prepared from the hydrolysis of corncob using the solid acid sulfated zirconia as a catalyst. According to response surface analysis experiments, the optimum conditions for preparing hemicellulosic hydrolysate catalyzed by sulfated zirconia were determined as follows: solid (sulfated zirconia)-solid (corncob) ratio was 0.33, solid (corncob)-liquid (water) ratio was 0.09, temperature was 153 °C, and time was 5.3 h. Under the optimized conditions, the soluble sugar concentration was 30.12 g/L with a yield of 033 g/g corncob. Subsequently, xylitol production from the resulting hemicellulosic hydrolysate was demonstrated by Candida tropicalis, and results showed that the yield of xylitol from the hemicellulosic hydrolysate could be significantly improved on a basis of decolorization and detoxification before fermentation. The maximum yield of xylitol from the hemicellulosic hydrolysate fermented by C. tropicalis was 0.76 g/g. This study provides a new attempt for xylitol production from the hemicellulosic hydrolysate.

Synthesis of Biopolymeric Drug Binder from Plant-based waste

Binders are agents employed to impart cohesiveness to the powdered material during the formulation of tablets which remains intact after compression. As part of continuing efforts to design a cost-effective pharmaceutical grade binder, two different types of plant-based polysaccharides such as hemicelluloses from corn cobs and mucilage from sapota seeds were extracted from domestic waste and used as a binder in amoxicillin tablet formulations using wet granulation technique. Finally the efficiency of the tablet was evaluated by different pre-compression and post-compression analysis. The in-vitro drug release profile of formulated tablets were assayed at different gastrointestinal tract pH. The extracted hemicellulose and mucilage were characterized by Fourier transform infrared spectroscopy (FTIR). All the formulations with natural polymers produced tablets easily and showed satisfactory results. The sapota seed mucilage exhibited better in vitro drug release profile than the corn cob hemicellulose. The dissolution time of the tablets was found to be increased with increase in polymer concentration. Tablets with highest binder concentration showed controlled released dissolution pattern which is more essential and requirement for a good binder. Formulated tablets with sapota seed polymer showed maximum drug release of 83.56% at pH 7.4, and 96.36% at pH 1.2, where the corn cob polysaccharide showed 68.9% at pH 7.4, and 90.9% at pH 1.2. On the basis of drug release behavior it can be summarized that corn cob hemicellulose and sapota seed mucilage can act as excellent binder in dosage forms. Since it is of natural origin and these biopolymers available at low cost it may prove to be better binder over commercially used costly synthetic binders.

Methane production by co-digestion of poultry manure and lignocellulosic biomass: Kinetic and energy assessment

Six typical Brazilian lignocellulosic biomasses (rice straw, corn cob, peanut shell, sawdust, coffee husk and sugarcane bagasse) were evaluated for methane production by solid-state anaerobic co-digestion with poultry manure. The results showed the highest methane production was obtained with corn cob and poultry manure (126.02 Nm3 CH4. ton residue−1) using a food to inoculum ratio of 0.5, which lowered volatile fatty acids accumulation. In this condition, the thermal energy production (1.73 MJ.kg live chicken−1) would be able to replace 53.2% of the energy with firewood in poultry farming. The high hemicellulose and low lignin content in corn cob seem to explain the biomethanation of such biomass, and this agrees with the microbial analysis which revealed the predominance of bacteria related to plant polysaccharides hydrolysis and carbohydrate conversion in the inoculum. The methane production was best modelled by Groot’s multi-stage model, and the microbial adaptation to lignin might explain this.

Efficient pretreatment of lignocellulosic biomass with high recovery of solid lignin and fermentable sugars using Fenton reaction in a mixed solvent

BackgroundPretreatment of biomass to maximize the recovery of fermentable sugars as well as to minimize the amount of enzyme inhibitors formed during the pretreatment is a challenge in biofuel process. We develop a modified Fenton pretreatment in a mixed solvent (water/DMSO) to combine the advantages of organosolv and Fenton pretreatments. The hemicellulose and cellulose in corncob were effectively degraded into xylose, glucose, and soluble glucose oligomers in a few hours. This saccharide solution, separated from the solid lignin simply by filtration, can be directly applied to the subsequent enzymatic hydrolysis and ethanol fermentation.ResultsAfter the pretreatment, 94% carbohydrates were recovered as soluble monosaccharide (xylose and glucose) and glucose oligomers in the filtrates, and 87% of solid lignin was recovered as the filter residue. The filtrates were directly applied to enzymatic hydrolysis, and 92% of raw corncob glucose was recovered. The hydrolysates containing the glucose and xylose from the enzymatic hydrolysis were directly applied to ethanol fermentation with ethanol yield equals 79% of theoretical yield. The pretreatment conditions (130 °C, 1.5 bar; 30 min to 4 h) are mild, and the pretreatment reagents (H2O2, FeCl3, and solvent) had low impact to environment. Using ferrimagnetic Fe3O4 resulted in similar pretreatment efficiency and Fe3O4 could be removed by filtration.ConclusionsA modified Fenton pretreatment of corncob in DMSO/water was developed. Up to 94% of the carbohydrate content of corncob was recovered as a saccharide solution simply by filtration. Such filtrate was directly applied to the subsequent enzymatic hydrolysis and where 92% of the corncob glucose content was obtained. The hydrolysate so obtained was directly applied to ethanol fermentation with good fermentability. The pretreatment method is simple, and the additives and solvents used have a low impact to the environment. This method provides the opportunity to substantially maximize the carbohydrate and solid lignin recovery of biomass with a comparatively green process, such that the efficiency of biorefinery as well as the bioethanol production process can be improved. The pretreatment is still relatively energy intensive and expensive, and further optimization of the process is required in large-scale operation.

Bamboo-derived magnetic carbonaceous solid acid catalyst for the conversion of corncob into furfural promoted by warm water immersion

In this study, a bamboo-derived magnetic carbonaceous solid acid catalyst (BC@Fe3O4@SO3H) was synthesized by FeCl3 impregnation, which was followed by incomplete carbonization and -SO3H group functionalization. FT-IR, XRD, and TGA results showed that the prepared catalyst contained -SO3H, -COOH, and phenolic -OH groups. It exhibited poor adsorption ability for the dominating sugars released during the catalytic conversion process. The prepared bamboo-derived magnetic carbonaceous solid acid presented high catalytic activity for depolymerization and conversion of corncob hemicellulose. Warm water immersion under 60 °C was able to destroy the complex corncob cell wall structure and accelerated the dissolution of carbohydrates. The highest furfural yield of 54.1 mg/g was obtained from 40 °C water-immersed corncob after reacting at 180 °C for 30 min. Up to 96.1% of the corncob hemicellulosic backbone sugars were depolymerized to monosaccharides and oligosaccharides in the hydrolysates. The prepared catalyst exhibited a simple magnetic recovery process and high stability. This work provides promising strategies for biomass utilization via renewable materials.

Preparation and investigation of highly selective solid acid catalysts with sodium lignosulfonate for hydrolysis of hemicellulose in corncob

Saccharification of lignocellulose is a necessary procedure for deconstructing the complex structure for building a sugar platform that can be used for producing biofuel and high-value chemicals. In this study, a carbon-based solid acid catalyst derived from sodium lignosulfonate, a waste by-product from the paper industry, was successfully prepared and used for the hydrolysis of hemicellulose in corncob. The optimum preparation conditions for the catalyst were determined to be carbonization at 250 °C for 6 h, followed by sulfonation with concentrated H2SO4 (98%) and oxidation with 10% H2O2 (solid–liquid ratio of 1 : 75 g mL−1) at 50 °C for 90 min. SEM, XRD, FT-IR, elemental analysis and acid–base titration were used for the characterization of the catalysts. It was found that 0.68 mmol g−1 SO3H and 4.78 mmol g−1 total acid were loaded onto the catalyst. When corncob was hydrolyzed by this catalyst at 130 °C for 12 h, the catalyst exhibited high selectivity and produced a relatively high xylose yield of up to 84.2% (w/w) with a few by-products. Under these conditions, the retention rate of cellulose was 82.5%, and the selectivity reached 86.75%. After 5 cycles of reuse, the catalyst still showed high catalytic activity, with slightly decreased yields of xylose from 84.2% to 70.7%.

Effective Utilization of Carbohydrate in Corncob to Synthesize Furfuralcohol by Chemical-Enzymatic Catalysis in Toluene-Water Media.

In this study, carbohydrates (cellulose plus hemicellulose) in corncob were effectively converted furfuralcohol (FOL) via chemical-enzymatic catalysis in a one-pot manner. After corncob (2.5g, dry weight) was pretreated with 0.5wt% oxalic acid, the obtained corncob-derived xylose (19.8g/L xylose) could be converted to furfural at 60.1% yield with solid acid catalyst SO42-/SnO2-attapulgite (3.6wt% catalyst loading) in the water-toluene (3:1, v/v) at 170°C for 20min. Moreover, the oxalic acid-pretreated corncob residue (1.152g, dry weight) was enzymatically hydrolyzed to 0.902g glucose and 0.202g arabinose. Using the corncob-derived glucose (1.0mM glucose/mM furfural) as cosubstrate, the furfural liquor (48.3mM furfural) was successfully biotransformed to FOL by recombinant Escherichia coli CCZU-A13 cells harboring an NADH-dependent reductase (SsCR) in the water-toluene (4:1, v/v) under the optimum conditions (50mM PEG-6000, 0.2mM Zn2+, 0.1g wet cells/mL, 30°C, pH6.5). After the bioreduction for 2h, FAL was completely converted to FOL. The FOL yield was obtained at 0.11g FOL/g corncob. Clearly, this one-pot synthesis strategy shows high potential application for the effective synthesis of FOL.

The green hydrolysis technology of hemicellulose in corncob by the repeated use of hydrolysate

Abstract To achieve green hydrolysis technology of hemicellulose through repeated using hydrolysate, the hydrolysis of hemicellulose in corncob was studied. The influence of repeated use of corncob hydrolysate on concentrations of d -xylose and l -arabinose was investigated. The loss rates of d -xylose in the prepared d -xylose solutions both with and without corncob, and repeated using corncob hydrolysate under identical acidity condition were discussed. The result shows that d -xylose concentration and l -arabinose concentration are all gradually increasing with the growing time of repeated use of corncob hydrolysate. After the fifth repetition, the concentrations of d -xylose and l -arabinose are 196.7 g·L − 1 and 22.0 g·L − 1 , respectively. Substance inhibiting the degradation of d -xylose is generated during repeated use of corncob hydrolysate, and the production is further proved by the change of d -xylose concentration and the loss rate of d -xylose over heating time.

Efficient utilization of hemicellulose and cellulose in alkali liquor-pretreated corncob for bioethanol production at high solid loading by Spathaspora passalidarum U1-58

The bioethanol fermentation of pretreated corncob was investigated using Spathaspora passalidarum U1-58, which simultaneously utilizes glucose and xylose for high-efficiency ethanol production. Two approaches, namely, separate hydrolysis and co-fermentation (SHCF) and simultaneous saccharification and co-fermentation (SSCF), were optimized to test the ethanol fermentation potential of U1-58. The highest ethanol titer of 42.46g/L and yield of 72.12% were acquired in SHCF, whereas 53.24g/L ethanol and yield of 75.35% were obtained in SSCF at solid-to-liquid ratio of 1:5 (w/v). Approximately 86.20% of cellulose and 82.99% of hemicellulose were consumed in SSCF after 96h, and at least 10.49g/L ethanol was produced from hemicellulose, which corresponded to 37.59% of the theoretical yield. Compared with the published cellulosic ethanol fermentation cases, the present work presented high ethanol titer and yield, and cellulose and hemicellulose could be efficiently utilized for ethanol production.