Cellulose Accessibility Research Articles

Enhancing for Bagasse Enzymolysis via Intercrystalline Swelling of Cellulose Combined with Hydrolysis and Oxidation.

To overcome the biological barriers formed by the lignin–carbohydrate complex for releasing fermentable sugars from cellulose by enzymolysis is both imperative and challenging. In this study, a strategy of intergranular swelling of cellulose combined with hydrolysis and oxidation was demonstrated. Pretreatment of the bagasse was evaluated by one bath treatment with phosphoric acid and hydrogen peroxide. The chemical composition, specific surface area (SSA), and pore size of bagasse before and after pretreatment were investigated, while the experiments on the adsorption equilibrium of cellulose to cellulase and reagent reuse were also performed. Scanning electron microscopy (SEM) and high-performance liquid chromatography (HPLC) were employed for microscopic morphology observations and glucose analysis, respectively. The results showed that pretreated bagasse was deconstructed into cellulose with a nanofibril network, most of the hemicellulose (~100%) and lignin (~98%) were removed, and the SSA and void were enlarged 11- and 5-fold, respectively. This simple, mild preprocessing method enhanced cellulose accessibility and reduced the biological barrier of the noncellulose component to improve the subsequent enzymolysis with a high glucose recovery (98.60%).

Alkalization of Kraft Pulps from Pine and Eucalyptus and Its Effect on Enzymatic Saccharification and Viscosity Control of Cellulose.

Bleached kraft pulps from eucalyptus and pine were subjected to cold caustic extraction (CCE) with NaOH (5, 10, 17.5, and 35%) for hemicelluloses removal and to increase cellulose accessibility. The effect of these changes was evaluated in enzymatic saccharification with the multicomponent Cellic CTec3 enzyme cocktail, and in viscosity reduction of pulps with the monocomponent Trichoderma reesei endoglucanase (EG). After CCE with 10% NaOH (CCE10) and 17.5% NaOH (CCE17.5), hemicellulose content lower than 1% was achieved in eucalyptus and pine pulps, respectively. At these concentrations, cellulose I started to be converted into cellulose II. NaOH concentrations higher than 17.5% decreased the intrinsic viscosity (from 730 to 420 mL/g in eucalyptus and from 510 to 410 mL/g in pine). Cellulose crystallinity was reduced from 60% to 44% in eucalyptus and from 71% to 44% in pine, as the NaOH concentration increased. Enzymatic multicomponent saccharification showed higher glucose yields in all CCE-treated eucalyptus samples (up to 93%) while only CCE17.5 and CCE35 pine pulps achieved 90% after 40 h of incubation. Untreated bleached pulps of both species presented saccharification yields lower than 70%. When monocomponent EG was used to treat the same pulps, depending on enzyme charge and incubation time, a wide range of intrinsic viscosity reduction was obtained (up to 74%). Results showed that eucalyptus pulps are more accessible and easier to hydrolyze by enzymes than pine pulps and that the conversion of cellulose I to cellulose II hydrate only has the effect of increasing saccharification of CCE pine samples. Viscosity reduction of CCE pulps and EG treated pulps were obtained in a wide range indicating that pulps presented characteristics suitable for cellulose derivatives production.

Pretreatment of corncob with green deep eutectic solvent to enhance cellulose accessibility for energy and fuel applications

Fossil fuels are the primary source of energy for a long period in spite of excessive environmental hazards, such as greenhouse gas emissions. Production of energy and fuel from lignocellulosic biomass has been the goal of the study in pursuit of renewable alternatives to fossil materials. Corncob is common agricultural biomass waste found in many countries. It can be utilized to produce bioenergy, but the conversion efficiency is limited. Pretreatment may be applied to improve the efficiency of corncob conversion; for example, by the fractionation of lignocellulosic biomass. Choline chloride (ChCl) and glycerol are considered as synthetic deep eutectic solvents (DESs), also known as green solvents. DESs are expected to fractionate hemicellulose and lignin from raw biomass, and the accessibility of cellulose may be enhanced. In this work, pretreatment of corncob with DES prepared from ChCl and glycerol was investigated at varying reaction temperatures (60–150 °C), residence times (6–15 h), and ChCl-to-glycerol molar ratios (1:0.5-4). The results showed that hemicellulose and lignin were effectively extracted from the raw corncob, and therefore, cellulose content in the remaining solid residue, known as cellulose-rich material (CRM), can be improved by least 140%. The reaction temperature, residence time, and presence of ChCl in the DES influenced the pretreatment of corncob significantly. Increases in reaction temperature and residence time led to a higher cellulose content in CRMs and an increased extraction of hemicellulose and lignin from the raw corncob. Without the ChCl in DES, the cellulose content in CRMs and the extraction of hemicellulose and lignin from the sample were decreased markedly. The optimal condition at 150 °C, 12-h residence time, and 1:4 ChCl-to-glycerol molar ratio could be used to improve the cellulose content of CRMs from the raw corncob by more than 150%. The CRM with improved lignocellulosic properties can be used as a feedstock in further bioenergy/fuel application.

Impact of different pretreatments on the anaerobic digestion performance of cucumber vine

Copious amounts of cucumber vine (CV) derived from crop growing and harvesting are casually discarded in the field, posing severely negative impacts on public health and the ecological environment. Treating CV via anaerobic digestion (AD) could represent a promising approach while the recalcitrant lignocellulosic structure restricts its conversion efficiency, thus underscoring the importance of valid pretreatments. This study systematically investigated the effects of nine types of commonly applied chemical pretreatments involved H2SO4, HCl, H3PO4, NaOH, KOH, Ca(OH)2, CaO, H2O2, and alkaline hydrogen peroxide (AHP) pretreatments on methane production of CV. Results showed that alkaline and AHP pretreatments were beneficial to the methane production of CV and obtained the considerable cumulative methane yield and biodegradability of 194.3-241.5mL·gVS-1 and 47.59-59.15%, respectively, 36.83-70.07% higher than untreated. Analyses of lignocellulosic compositions and structural characterizations revealed that alkaline and AHP pretreatments well destroyed both hemicellulose and lignin, which commendably increased the accessibility of cellulose, facilitating the methane production. The findings of this study provide not only efficient pretreatment methods for the disposal and utilization of CV during AD process but also promising alternatives for enhancing methane production performance of similar vine residues, which would be greatly valuable for industrial applications in the future.

Silica extraction followed by biogas generation from rice straw: Investigating the impact of pretreatment on purity of silica, biogas yield and microbial diversity along with insights on techno-economic analysis

Valorisation of agriculture waste namely rice straw (RS) for the recovery of value-added products such as high purity silica and biogas has gained tremendous research interest. Presence of silica and lignin limits the utilization of these wastes as potential feedstock for biological treatment. Therefore, this study investigated the impact of alkali (NaOH) pre-treatment at varied concentration of 2%, 4%, 6%, 8%, and 10% (w/v)) on lignin and silica removal at 90 °C so that the silica can be recovered as a value-added product and the lignin free biomass can be utilized as feedstock to estimate the biogas generation at mesophilic temperature (35 ± 2 °C) for 45 days. The impact of pre-treatment was studied and supported by the SEM, FTIR for morphological, and compositional variations while the AD is supported by 16 s rRNA metagenomic sequencing. Results revealed that increasing the concentration of NaOH up to 8% improved silica extraction with a purity of 97.34% with simultaneous lignin removal by 50 – 70%. Pretreatment with 2% NaOH was more effective in facilitating the accessibility of cellulose and hemicellulose to microbes during AD. In summary, this study concludes 2% NaOH treatment is ideal for both silica and biogas recovery.

Co-production of levulinic acid and lignin adsorbent from aspen wood with combination of liquid hot water and green-liquor pretreatments

Efficient lignocellulosic fractionation and conversion into platform chemicals provide a considerable opportunity for the industrial operation of a lignocellulosic biorefinery. However, single-step pretreatments are often insufficient to overcome biomass recalcitrance as the existence of insoluble lignin generally restricts component fractionation and conversion. This study performed a two-step pretreatment, consisting of sequential liquid hot water (LHW) and green-liquor (GL), for bioprocessing of aspen biomass into bioproducts such as glucose, levulinic acid (LA), and lignin adsorbent. The two-step pretreated glucan-rich solid displayed high cellulose accessibility, which is responsible for 94% of the glucose yield. The optimized LHW pretreatment (200 °C, 40 min) solubilized 91% of the hemicellulose, which together with monomeric sugars in the hydrolysate solution was straightly heated at 190 °C for 80 min and yielded 72.49% of LA in the presence of sulfuric acid as a catalyst. Moreover, GL post-treatment (Na2CO3+Na2SO3) solution maximized the delignification at 78% from LHW pretreated substrate. The isolated lignin possessed a remarkable ability for Cd2+ and Pb2+ uptake with maximized adsorption values of 250 mg/g and 228 mg/g, respectively. Finally, energy analyses showed that moderate lignocellulosic conversion could obtain an energy recovery of 85%, providing a sustainable pathway for biorefinery approaches.

Upcycling agricultural waste to biodegradable polyhydroxyalkanoates by combined ambient alkaline pretreatment and bacterial fermentation

Medium-chain-length polyhydroxyalkanoates (mcl-PHAs), polyesters produced by bacterial fermentation of sugars and/or lipids, are potential bioplastic alternatives to petroleum-derived plastics. Lignocellulose is an abundant renewable source of sugars for bacterial fermentation. However, chemical or enzymatic release of the sugars requires a pretreatment step to dispel the rigid structure of the lignocellulose and enhance sugar access. Most pretreatments of lignocellulose involve high temperature and/or pressure, which increases processing and production costs and discourages commercialization. Here we demonstrate a chemical-biological pathway for mcl-PHAs production from rice straw and hemp hurd. We combined ambient alkaline pretreatment, enzymatic hydrolysis, and bacterial fermentation. The alkaline pretreatment reduced the particle size of pretreated solids and partially fractionated hemicellulose and lignin; these effects increased cellulose accessibility to enzymes and enabled a high sugar release (78–83% glucose yield) at a high solid loading (9 wt%). Therefore, we obtained 47 wt% and 69 wt% mcl-PHAs (with respect to gram of dry cell weight) from pretreated rice straw and hemp hurd, respectively. These findings constitute an energy-efficient pretreatment process that can be extended to other sources of lignocellulose, such as woody biomass and dedicated bioenergy crops. Moreover, mcl-PHAs from lignocellulose provide revenue to the agricultural sector, mitigate global warming from fossil fuel processing, and potentially reduce plastic pollution.

Coproduction of xylooligosaccharides and monosaccharides from hardwood by a combination of acetic acid pretreatment, mechanical refining and enzymatic hydrolysis

Sequential biorefinery treatments of acetic acid (HAC) pretreatment, Papir Forsknings Institutet (PFI) milling and enzymatic hydrolysis were demonstrated for coproduction of xylooligosaccharides (XOS) and fermentable monosaccharides. Results indicated that 36.2% XOS (50.8% X2-X3) and 17.0% low DP xylans were achieved using a HAC pretreatment with a combined severity factor of 0.78. The HAC pretreatment resulted in a XOS-rich prehydrolyzate with a low molecular weight of 1.28 kDa. The endo-xylanase hydrolysis was conducted on the pretreatment liquor to elevate XOS yield and the content of higher-value X2-X3. Moreover, fermentable glucose production from the pretreated residue increased by 2.3 folds when introducing an additional step of PFI refining prior to enzymatic digestion. Properties of substrate including cellulose accessibility, crystallite size, crystalline index and water retention value were in close relationships with enzymatic digestibility. The implementation of proposed biorefinery process will give more insights into the efficient construction of a wood-derived sugar platform.

Alkaline deacetylation-aided hydrogen peroxide-acetic acid pretreatment of bamboo residue to improve enzymatic saccharification and bioethanol production

Bamboo pretreatment with alkaline deacetylation-aided hydrogen peroxide-acetic acid (HPAC-NaOH) was investigated for producing high-value-added products. Comparing with HPAC pretreated D. sinicus, the post-treatment of alkaline deacetylation resulted in higher glucose yield of 91.3% and ethanol concentrations of 17.20 g/L, increased by about 20–27%. A strong negative correlation between the content of acetyl with cellulose accessibility and enzymatic hydrolysis yield was showed. The deacetylation of HPAC-DS contributed to the increase of cellulase adsorption capacities in substrates and the variations of hydrophilicity, cellulose crystallinity, and degree of polymerization, which can generate highly reactive cellulosic materials for enzymatic saccharification to produce bioethanol. The HPAC-NaOH pretreatment can provide a promising approach to improve the bioconversion of bamboo to biofuels, and has broad space for the biorefinery of bamboo in the south of China.

Real-time imaging of enzymatic degradation of pretreated maize internodes reveals different cell types have different profiles

This work presents a dynamic view of the enzymatic degradation of maize cell walls, and sheds new light on the recalcitrance of hot water pretreated maize stem internodes. Infra-red microspectrometry, mass spectrometry, fluorescence recovery after photobleaching and fluorescence imaging were combined to investigate enzymatic hydrolysis at the cell scale. Depending on their polymer composition and organisation, cell types exhibits different extent and rate of enzymatic degradation. Enzymes act sequentially from the cell walls rich in accessible cellulose to the most recalcitrant cells. This phenomenon can be linked to the heterogeneous distribution of enzymes in the liquid medium and the adsorption/desorption mechanisms that differ with the type of cell.

Promoting transfer of endogenous electrons well increases the carbon and energy efficiency of lignocellulosic biomass conversion to fuels and chemicals

A new coupled process was developed by combining several technologies including biomass pretreatment, direct biomass-to-electricity conversion and electrochemical reduction of the CO2 produced during microbial fermentation of the enzymatic hydrolysate of pretreated substrates. This process was achieved by the assistance of several electron carriers for mediating the transfer of biomass endogenous electrons. Pretreatment of corn stover to increase cellulose accessibility for bioethanol production with the electron carriers being reduced works as a “charging” or “electron extraction” step. Re-oxidization of the reduced electron carriers in a liquid flow fuel cell works as an “electricity generation” step. Electrochemical reduction of CO2 to form formic acid with co-production of hydrogen gas works as an “electricity consumption” step. Under the respective optimal condition of each step, this coupled process would obtain 155.6 g bioethanol, 145.3 g formic acid and 23.3 g hydrogen gas from 1000 g corn stover, achieving 47.0% increase in carbon efficiency and 88% increase in system energy efficiency. This coupled process could well increase the carbon efficiency of lignocellulose polysaccharide conversion, which thus may provide new technical routes for lignocellulose conversion with more carbon negativity.

Exploration of deep eutectic solvent-based biphasic system for furfural production and enhancing enzymatic hydrolysis: Chemical, topochemical, and morphological changes

Developing a biorefinery process for a highly integrated valorization and fractionation of lignocellulose is crucial for its utilization. Herein, a biphasic system comprising choline chloride/lactic acid and 2-methyltetrahydrofuran with Al2(SO4)3 and H2SO4 as catalysts was applied to pretreat Eucalyptus. Results showed that under the optimized conditions (150 °C, 30 min, 0.2 M Al2(SO4)3, 0.075 M H2SO4), the furfural yield and enzymatic hydrolysis efficiency could reach 54.7% and 97.0%, respectively. The efficient cellulose conversion was attributed to remarkable removal of lignin (91.0%) and hemicelluloses (100.0%), thereby causing the disruption of cell wall structure and enhancement of cellulose accessibility. Meanwhile, confocal Raman microscope and atomic force microscope displayed that the pretreatment resulted in the decreasing intensities of carbohydrates and lignin different regions of cell walls, and exposing of the embedded microfibers from noncellulosic polymers. Overall, the deep eutectic solvent-based biphasic system displayed high performance for effective utilization of carbohydrate components in lignocellulose.

Ultrafast improvement of cellulose accessibility via non-dissolving pretreatment with LiBr·3H2O under room temperature

The development of sustainable and effective pretreatment methods to improve the accessibility of cellulose is of vital importance for its utilization. Herein, a novel high-efficiency pretreatment method based on lithium bromide trihydrate (LBTH) was established, which realized the fast improvement of cellulose accessibility under ambient conditions without dissolution of cellulose. The cellulose I structure of microcrystalline cellulose (MCC) was transformed into amorphous structure just within 5 min of LBTH pretreatment, and the crystallinity was reduced from 79.1 to 19.9%. After pretreatment for 30 min, the BET surface area of MCC increased from 2.1 to 125.9 m2/g. Particularly, the pretreated cellulose could be near-completely saccharified to glucose (98.3%) with ultra-low enzyme dosage (2.5 mg protein/g-glucan) just within 24 h, while the conversion of untreated MCC under the same conditions was only 16.7%. Additionally, this non-dissolving pretreatment is beneficial to the separation and recycling of LBTH, guaranteeing a clean and sustainable process.

Enhancing enzymatic digestibility of bamboo residues using a three-constituent deep eutectic solvent pretreatment

A three-constituent deep eutectic solvent (3c-DES) pretreatment with choline chloride-oxalic acid-ethylene glycol was applied to examine its effectiveness on bamboo residues. The 3c-DES pretreatment can remove 91.09% xylan and significantly improved the 72 h hydrolysis yield of D. sinicus by 6.3 and 1.7 times as compared with the liquid hot water and two-constituent deep eutectic solvent (2c-DES) pretreatment. The introduction of ethylene glycol (EG) into choline chloride (ChCl)/ oxalic acid (OA) decreased the content of surface lignin and the condensation of lignin, which contributed to the increase of hydrophilic nature and cellulose accessibility in substrates. Moreover, higher glucose (85.72%) and xylose (91.05%) yields of 3c-DES pretreated bamboo were achieved with the addition of Tween 80. The 3c-DES system provides an alternative approach for the development of efficient bamboo pretreatment, and had broad space for bamboo biorefinery in southern China.

Enhanced Saccharification of Purple Alfalfa via Sequential Pretreatment with Acidified Ethylene Glycol and Urea/NaOH

Purple Alfalfa is an inexpensive, abundant, readily available lignocellulosic material. This work was attempted to develop an efficient combination pretreatment by sequential HClO4–ethyl glycol–H2O (1.2:88.8:10, w/w/w) extraction at 130 °C in 0.5 h and urea/NaOH (urea 12 wt%, NaOH 7 wt%) soaking at −20 °C for 0.5 h for the pretreatment of purple alfalfa. The porosity, morphology, and crystallinity of pretreated purple alfalfa were characterized with SEM, FM, XRD, and FTIR. This combination pretreatment had a significant influence on hemicellulose removal and delignification. The above changes could enhance cellulose accessibility to enzymes and improve the enzymatic digestibility of cellulose. High yields of reducing sugars from pretreated purple alfalfa were obtained at 93.4%. In summary, this combination pretreatment has high potential application in the future.

Insight into the negative effects of lignin on enzymatic hydrolysis of cellulose for biofuel production via selective oxidative delignification and inhibitive actions of phenolic model compounds

Oxidative pretreatment of wheat straw with sodium chloride has been used for selective delignification to obtain ideal samples to understand the negative effects of lignin on cellulose accessibility of lignocellulosic biomass. Strong interactive effects has been found between hemicellulose and lignin. To achieve a high enzymatic glucan conversion (EGC) (>80% with 20 FPU/g solid) in the case of high xylan content (25–30%), a moderate degree of delignification (56.3%) with relatively low lignin content (11.9%) is necessary; while in the case of low xylan content (2.6–3.9%), slight removal of lignin by oxidative treatment can well increase cellulose digestibility with a final EGC reaching 90% even that the residual lignin content is as high as 30.9%. Delignification greatly modifies substrate surface morphology with deformation, fracture of cell wall layers and even disappearance of middle lamella. Oxidation also modifies the functional groups and surface properties of lignin, leading to reduction in the inhibitive effects. Phenolic hydroxyl group (Ph-OH) in p-hydroxyphenyl unit has been found to show the strongest inhibition to filter paper activity of cellulase cocktail. Ph-OH exerts stronger inhibition to β-glucosidase than to the endo- and exo-glucanases. Hydrogen bonding and electrostatic interaction are primarily responsible for the inhibitive action of Ph-OH.

Tuning hydrothermal pretreatment severity of wheat straw to match energy application scenarios

Wheat straw was hydrothermally pretreated over a broad severity range (90–300 °C) to comparatively assess its suitability for energy application scenarios. Although the substrate was not completely deconstructed at the rather low temperature of 120 °C, the biomethane yield through whole slurry anaerobic digestion was 32% higher than that of unpretreated wheat straw. It was proposed that an increasing amount of soluble fractions was released at higher pretreatment temperatures, which consequently limited anaerobic digestion through the acidification or inhibition mechanism; therefore a lower biomethane yield was obtained. In contrast to the profile of anaerobic digestion, increasing the pretreatment temperature significantly facilitated bioethanol production through simultaneous saccharification and fermentation (SSF). When the hydrothermal pretreatment was performed at 210 °C, the ethanol yield was 229.5% higher than that of the untreated wheat straw. The possible reason was that at higher temperatures, the recalcitrant fraction of hemicellulose tended to solubilize through auto acid-catalyzed hydrolysis, which enhanced the accessibility of cellulose to cellulase enzymes. At very high hydrothermal temperatures (≥240 °C), the pretreated substrates were not suitable for biological conversion but were well suited for production of carbons with an ultra-high surface area. In conclusion, lower pretreatment temperatures are recommended for anaerobic digestion, moderate temperatures for SSF, and high temperatures for non-biological conversion to produce supercapacitor carbon electrodes.

Using poly(N-Vinylcaprolactam) to Improve the Enzymatic Hydrolysis Efficiency of Phenylsulfonic Acid-Pretreated Bamboo.

Chemical pretreatment followed by enzymatic hydrolysis has been regarded as a viable way to produce fermentable sugars. Phenylsulfonic acid (PSA) pretreatment could efficiently fractionate the non-cellulosic components (hemicelluloses and lignin) from bamboo and result in increased cellulose accessibility that was 10 times that of untreated bamboo. However, deposited lignin could trigger non-productive adsorption to enzymes, which therefore significantly decreased the enzymatic hydrolysis efficiency of PSA-pretreated bamboo substrates. Herein, poly(N-vinylcaprolactam) (PNVCL), a non-ionic surfactant, was developed as a novel additive for overcoming the non-productive adsorption of lignin during enzymatic hydrolysis. PNVCL was found to be not only more effective than those of commonly used lignosulfonate and polyvinyl alcohol for overcoming the negative effect of lignin, but also comparable to the robust Tween 20 and bovine serum albumin additives. A PNVCL loading at 1.2 g/L during enzymatic hydrolysis of PSA pretreated bamboo substrate could achieve an 80% cellulosic enzymatic conversion and meanwhile reduce the cellulase loading by three times as compared to that without additive. Mechanistic investigations indicated that PNVCL could block lignin residues through hydrophobic interactions and the resultant PNVCL coating resisted the adsorption of cellulase via electrostatic repulsion and/or hydration. This practical method can improve the lignocellulosic enzymatic hydrolysis efficiency and thereby increase the productivity and profitability of biorefinery.

Pretreatment of corn cobs and corn stalks with tetrabutyl phosphate hydroxide ionic liquid to enhance enzymatic hydrolysis process

The abundant lignocellulosic biomass used to produce biofuels was considered the most promising alternative to fossil fuels. In view of this, many studies directly use ionic liquids (ILs) to pretreat lignocellulose for subsequent fermentation. Herein, the strong proton acceptor tetrabutyl phosphorus hydroxide (TBPH) aqueous solution was employed to pretreat corn cobs and corn stalks. The effects of pretreatment time (0.5–2 h), temperature (20–80 ℃), TBPH aqueous solution concentration (10–40 wt%) and liquid to solid ratio (4 wt/wt-9 wt/wt) on the components and sugar yield were investigated. For the pretreatment of corn cob and corn stalk, the sugar yield was 90.75% and 80.84%, which were about 4 and 4.6 folds of the raw materials (unpretreated corn cob: 22.5% and unpretreated corn stalk: 17.7%). Characterization results confirmed that the lignin and hemicellulose were significantly removed, and the cellulose crystals remained intact. Before and after pretreatment, the two raw materials changed from the initial dense surface morphology to porous and therefore contributed to enhancing the accessibility of cellulose during enzymatic hydrolysis. Furthermore, the sugar yield could still be maintained above 70% after the TBPH aqueous solution was reused 5 times. These results provide guidance for the conversion of other biomass to sugar and further fermentation to prepare the essential products.

Sodium Hydroxide Treatment for Cellulose Fiber Accessibility from Corncobs under Microwave Assistive

Corncob is abundantly available lignocellulosic biomass resources obtained from crops harvesting and found to be solid waste accumulation on a field. Less corncob is used as a solid fuel for cooking, and a more significant portion is vanished on the field by burning. Promisingly, corncob contains considerable cellulose as one value-added component potentially utilized as biomaterial or biofuel feedstock. However, the presence of lignin in natural lignocellulosic biomass results in recalcitrant structure and hinders cellulose accessibility. This study aimed to investigate microwave-assisted alkaline treatment to retain cellulose in the solid product while removing other impurities in corncob, especially hemicellulose and lignin. Sodium hydroxide was selected as a chemical with some variations in concentration. The chemical treatment was carried out under 400 W microwave power with various residence times and a 1:10 solid to liquor ratio. The cellulose content upgraded from 26.97% to 71.26% while reducing hemicellulose and lignin from 38.49% to 18.15% and 19.28% to 6.4%, respectively, on chemical treatment using 8% sodium hydroxide concentration for 20 minutes residence time. Scanning electron microscope (SEM) and Fourier transform infrared (FTIR) analysis also confirmed the results. The treated corncob also increased its crystallinity from 30.11% to 52.91%.