Hemicellulose Extraction Research Articles

Hydrolysis of semi‐industrial aqueous extracted xylan from birch (Betula pendula) employing commercial catalysts: kinetics and modelling

AbstractBACKGROUNDAcidic hydrolysis of a birch (Betula pendula) xylan produced by a novel semi‐industrial‐scale aqueous‐based and highly sustainable method was studied in a batch reactor. Five commercial acidic heterogeneous catalysts were screened and significant differences in their performance were observed. Dowex 50WX2‐100 was selected for further studies and the influence of the reaction parameters, including stirring speed, pH (0.5–1.5), temperature (115–145 °C) and catalyst particle size (50–400 mesh) were studied. The goal was to maximize xylose yield by balancing between the kinetics of hydrolysis and the undesired degradation of monosaccharides.RESULTSThe results show that the maximum achieved yield of xylose was 76%, but higher yields were hindered by the consecutive dehydration of sugars. It was also observed that the hydrolysis and dehydration reactions do not follow the same dependence on the experimental parameters, which leaves room for optimization of the yield. A kinetic model was developed based on the data, which takes into account the consecutive reaction pathway and the influence of the experimental conditions, and a very good fit of the model to the experimental data was achieved. An activation energy of 119 and 88 kJ mol–1 was obtained for the hydrolysis and dehydration steps, respectively.CONCLUSIONHydrolysis results of this novel, well‐characterized hemicellulose extract have not been published previously, and they contribute significantly to the understanding of the hydrolysis and dehydration of real feedstock, instead of highly purified and typically very deacetylated model compounds with different characteristics and behaviour in hydrolysis. © 2021 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Selective Oxidation of Arabinose on Gold Catalysts: Process Design and Techno‐economic Assessment

AbstractThe present work focuses on process design and techno‐economic assessment of the oxidation of a pentose sugar present in hemicelluloses, i.e., arabinose, on a supported gold catalyst. The processing plant was designed with Aspen Plus. The arabinose feedstock price has an important impact on the operational performance contributing to almost half of these costs. The feasibility of the overall arabinose oxidation process requires efficient extraction of hemicellulose from the lignocellulosic biomass lowering the feedstock costs.

Recent Developments and Applications of Hemicellulose From Wheat Straw: A Review

Hemicellulose is an important component of plant cell walls, which is mainly used in biofuels and bioproducts. The hemicellulose extracted from different plant sources and plant locations has different microstructure and molecule. Wheat straw is an important biomass raw material for the extraction of hemicellulose. The aims of this review are to summary the recent developments and various applications of hemicellulose from wheat straw. The microstructure and molecule of hemicellulose extracted by different methods are comparably discussed. The hemicellulose-based derivatives and composites are also reviewed. Special attention was paid to the applications of hemicellulose such as biofuel production, packaging field, and adsorbent. The problems and developing direction were given based on our knowledge. We expect that this review will put forward to the development and high-value applications of hemicellulose from wheat straw.

Obtaining Fermentable Sugars from a Highly Productive Elm Clone Using Different Pretreatments

The interest of supplying lignocellulosic materials for producing fermentable sugars has recently emerged in order to diminish the negative environmental effects of fossil fuels. In this study, the Ulmus minor clone Ademuz, characterized for its tolerance to Dutch elm disease and its rapid growth, was evaluated as a source of fermentable sugars. For that, different pretreatments, comprising autohydrolysis, dilute acid hydrolysis, acid catalyzed organosolv, and alkaline extraction, were evaluated at two levels of severity (pretreatment temperatures at 160 °C and 180 °C, except for alkaline extraction at 80 °C and 160 °C); and the resulting pretreated materials were enzymatically hydrolyzed for fermentable sugars production. The major extraction of lignin and hemicellulose was achieved during organosolv (48.9%, lignin; 77.9%, hemicellulose) and acid hydrolysis (39.2%, lignin; 95.0%, hemicellulose) at 180 °C, resulting in the major enzymatic digestibility (67.7%, organosolv; 53.5% acid hydrolysis). Contrarily, under the most favorable conditions for autohydrolysis (180 °C) and alkaline extraction (160 °C), lower extraction of lignin and hemicellulose was produced (4.8%, lignin; 67.2%, hemicellulose, autohydrolysis; 22.6%, lignin; 33.1%, hemicellulose, alkaline extraction), leading to lower enzymatic digestibility (32.1%, autohydrolysis; 39.2%, alkaline extraction). Taking into account the sugars produced during enzymatic hydrolysis of pretreated materials and the solubilized sugars from pretreatment liquors, the highest sugars (glucose and xylose) yield production (28.1%) per gram of biomass from U. minor clone Ademuz was achieved with acid catalyzed organosolv at 180 °C.

Tagasaste, leucaena and paulownia: three industrial crops for energy and hemicelluloses production

BackgroundBurning fast-growing trees for energy production can be an effective alternative to coal combustion. Thus, lignocellulosic material, which can be used to obtain chemicals with a high added value, is highly abundant, easily renewed and usually inexpensive. In this work, hemicellulose extraction by acid hydrolysis of plant biomass from three different crops (Chamaecytisus proliferus, Leucaena diversifolia and Paulownia trihybrid) was modelled and the resulting solid residues were used for energy production.ResultsThe influence of the nature of the lignocellulosic raw material and the operating conditions used to extract the hemicellulose fraction on the heat capacity and activation energy of the subsequent combustion process was examined.The heat power and the activation energy of the combustion process were found to depend markedly on the hemicellulose content of the raw material. Thus, a low content in hemicelluloses resulted in a lower increased energy yield after acid hydrolysis stage.The process was also influenced by the operating conditions of the acid hydrolysis treatment, which increased the gross calorific value (GCV) of the solid residue by 0.6–9.7% relative to the starting material. In addition, the activation energy of combustion of the acid hydrolysis residues from Chamaecytisus proliferus (Tagasaste) and Paulownia trihybrid (Paulownia) was considerably lower than that for the starting materials, the difference increasing with increasing degree of conversion as well as with increasing temperature and acid concentration in the acid hydrolysis.The activation energy of combustion of the solid residues from acid hydrolysis of tagasaste and paulownia decreased markedly with increasing degree of conversion, and also with increasing temperature and acid concentration in the acid hydrolysis treatment. No similar trend was observed in Leucaena diversifolia (Leucaena) owing to its low content in hemicelluloses.ConclusionsAcid hydrolysis of tagasaste, leucaena and paulownia provided a valorizable liquor containing a large amount of hemicelluloses and a solid residue with an increased heat power amenable to efficient valorization by combustion. There are many potential applications of the hemicelluloses-rich and lignin-rich fraction, for example as multi-components of bio-based feedstocks for 3D printing, for energy and other value-added chemicals.

Dissolution of wood components during hot water extraction of birch

Autohydrolysis-based pretreatments enable extraction of hemicellulose from wood tissue prior to the paper pulp cooking processes enabling their further use as platform chemicals and in material applications. In this study, hot water extraction of birch meal was conducted in a small flow-through system. The combination of high surface area of the milled material with increased driving force induced by constant flow of freshwater, together with fast evacuation of extract, enabled a detailed study of the dissolution process. Based on the findings, deeper insight into acidification and autohydrolysis progress was obtained.

Green, efficient extraction of bamboo hemicellulose using freeze-thaw assisted alkali treatment

The premise of high value utilization of lignocellulosic biomass is effective separation of hemicellulose. In this paper, the extraction of bamboo hemicellulose using freeze-thaw assisted alkali treatment (FAT) was studied. The effect of alkali concentration, alkali treatment time, freezing temperature, and freeze-thaw time on the main components was studied. Bamboo was frozen at −30 °C for 12 h, thawed at room temperature, and then treated at 75 °C for 90 min with 7.0% alkali. The extraction rate of hemicellulose was as high as 64.71%. The purity of hemicellulose samples using conventional AT decreased from 82.63% to 78.56%. Hemicellulose with the same yield as that of conventional alkali treatment was obtained by further reducing the alkali concentration. The purity of hemicellulose samples increased from 82.63% to 89.45%. It had a higher purity, higher molecular weight, and lower polydispersity. A new, green and efficient alkaline extraction method for hemicellulose was developed.

Structural, morphological and thermal properties of microcrystalline cellulose extracted from coconut husk fiber

In this work, chemically treated microcrystalline cellulose (MCC-C) was extracted from coconut husk fiber. In order to extract hemicellulose, the sieved coconut husk fiber was treated with sodium hydroxide (NaOH) for dewaxing and acidified using sodium chlorite (NaClO2) to extract the residual lignin (bleaching process). The obtained lignin-free cellulose was then treated with potassium hydroxide (KOH). The characterizations used to equate the MCC-C with commercial grade microcrystalline cellulose (MCC) are solubility test, X-ray diffractogram (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The XRD showed that the crystallinity of MCC and MCC-C increased significantly by 80.15% and 71.8% by chemical treatments. TGA found that the active removal of lignin-hemicelluloses and the thermal stability of the material were about 350–500°C and 300–500°C. The morphology of the fiber confirmed that there is an irregular cross-section, non-uniform surface, a large amount of short microfibrils and some impurities on the surface of the coconut husk fiber. The findings showed that microcrystalline cellulose has been successfully extracted from coconut husk fiber and that it can be used further.

An integrated approach for hemicellulose extraction from forest residue

An alkali-mediated hydrothermal approach was optimized for partial extraction of high-purity hemicellulose (xylan) from a timber waste product (unbleached eucalyptus sawdust). The extraction process was: a) extractives removal using sequential solvent extraction; b) alkali-mediated hydrothermal extraction of hemicellulose; and c) purification of the isolated hemicellulose fraction. Biomass was extracted in an autoclave at a fixed temperature of 121 °C while varying the extraction time (1 h to 2.5 h) and alkali concentration (10%, 15%, and 20% w/v). Using this simple approach, high purity polymeric hemicellulose with molecular mass (21 to 30 kDa) was recovered in yields of 35 to 37%. The isolated hemicellulose can be chemically transformed into high-value commercial products such as prebiotics (xylooligosaccharides), surfactants, hydrogels, and food packaging materials. The purified residue can be utilized in existing kraft pulping processes. The integration of hemicellulose extraction into existing pulping process represents additional valorization of timber resources.

Wood/polyimide composite via a rapid substitution compositing method for extreme temperature conditions

Wood is a common-sense thermostable construction material, but the decrease in its structural stability and mechanical strength due to the degradation of lignin and hemicelluloses limits its practical applications in extreme environments. Here, we synthesize a high-performance wood/polyimide composite via the partial substitution of lignin and hemicellulose with super thermostable polyimide. This method involves the rapid partial removal of lignin and hemicellulose in only 3 min using microwave-assisted deep eutectic solvent (DES) pretreatment and subsequent impregnation of polyimide into the pretreated wood. The microwave-assisted DES pretreatment greatly reduced the processing time for lignin and hemicellulose extraction, while preserving the natural cellular scaffold of wood and opening more channels for polyimide infiltration. The obtained wood/polyimide composite showed a 17% improved Young's modulus and a 63% higher dynamic storage modulus than natural wood. The temperature of the first maximum decomposition rate of the wood/polyimide composite significantly increased to 290 °C due to the infiltration of the thermostable polyimide. Furthermore, the wood/polyimide composite exhibited a smoke suppression property (33% decrease), and the time to produce smoke was delayed by 200 s. Our work provides a rapid pretreatment method for wood and a substitution compositing method to produce wood-framed polyimide composites with excellent thermostability.

Investigation of choline chloride-formic acid pretreatment and Tween 80 to enhance sugarcane bagasse enzymatic hydrolysis

In this study, a pretreatment that consisting of choline chloride (ChCl) and formic acid (FA) were performed to improve sugarcane bagasse (SCB) enzymatic hydrolysis. Results showed that the ChCl-FA pretreatment exhibited an extraordinary ability to selectively extract hemicellulose (~95.6%) and degrade a large number of lignin (~72.6%) at 110 °C for 120 min, which enhanced the enzymatic hydrolysis of pretreated SCB. Besides, the impact of various additives on pretreated substrate enzymatic hydrolysis confirmed that Tween 80 was the best enzymatic additive, which could significantly improve the glucose produced from pretreated SCB and remarkably reduce the hydrolysis time (from 72 h to 48 h) and enzyme dosage (from 20 FPU/g pretreated solid to 10 FPU/g pretreated solid). In summary, the coupling of ChCl-FA pretreatment and Tween 80 exhibited a promising way to enhance the sugar release from SCB.

Utilization of Cereal Crop Residues, Cereal Milling, Sugarcane and Dairy Processing By-Products for Sustainable Packaging Solutions

Residues and by-products are the unavoidable outputs of cereal, sugarcane and dairy processing industry which can be resorted economically. Widespread focus on plastic replacement, residue burning and waste reduction had led to characterization and identification of by-products for economic packaging applications. Extensive research work had been done on whey usage in eco-friendly packaging but packaging applications of cereal crop residues, cereal milling by-products and sugarcane bagasse are still in nascent stage. However, research studies on extraction and exploitation of cellulose, hemicellulose and other film forming components from these by-products had been reported for packaging applications but described processes have low techno-commerciality. Current status and innovations in utilization of cereal residue (rice straw, wheat straw and corn cob), cereal milling by-products (husk, hull and bran), sugarcane processing waste (bagasse and sugar beet pulp) and whey based packaging applications as well as application in bio-composites, are discussed briefly in this review.

Acid-catalyzed fractionation of almond shells in γ-valerolactone/water

The fractionation of almond shells, an agro-industry residue available in some Mediterranean climate regions, was investigated using acid-catalyzed hydrolysis in γ-valerolactone (GVL)/water. A set of non-isothermal experiments at nominal temperatures of 120, 140, and 160 °C and sulfuric acid concentrations from 25 to 75 mM were developed using a constant 80% w/w GVL in water concentration and a reaction time of up to 120 min. GVL was an efficient medium and promoted solubilization of both lignin and hemicellulose, even at low temperature during the initial period of reactor heating, while cellulose conversion was limited. A temperature of 160 °C gave the highest extraction of lignin and hemicellulose, but recovery of hemicellulose carbohydrates was better below 140 °C. Sulfuric acid concentrations above 45 mM promoted excessive dehydration of xylose and glucose to furans and humins, which were recovered with lignin. A model was developed to describe the kinetics of lignin and hemicellulose solubilization. It distinguished three fractions of different reactivity in each polymer (lignin or hemicellulose): fast-reacting, slow-reacting, and unreactive. The amount of each fraction was correlated with acid concentration and reaction temperature. Activation energies and the other parameters in the model were obtained numerically by least-squares optimization using the data from the non-isothermal experiments. Activation energies for the fast-reacting and slow-reacting fractions of hemicellulose were 142 and 39.7 kJ mol−1, and for those of lignin 134 and 71.7 kJ mol−1, respectively. Acid concentration had a larger influence than temperature on establishing the amounts of slow-reacting hemicellulose and lignin, whereas temperature was the dominant variable concerning the fractions of non-reacting polymers.

Escherichia coli O157:H7 F9 Fimbriae Recognize Plant Xyloglucan and Elicit a Response in Arabidopsis thaliana.

Fresh produce is often a source of enterohaemorrhagic Escherichia coli (EHEC) outbreaks. Fimbriae are extracellular structures involved in cell-to-cell attachment and surface colonisation. F9 (Fml) fimbriae have been shown to be expressed at temperatures lower than 37 °C, implying a function beyond the mammalian host. We demonstrate that F9 fimbriae recognize plant cell wall hemicellulose, specifically galactosylated side chains of xyloglucan, using glycan arrays. E. coli expressing F9 fimbriae had a positive advantage for adherence to spinach hemicellulose extract and tissues, which have galactosylated oligosaccharides as recognized by LM24 and LM25 antibodies. As fimbriae are multimeric structures with a molecular pattern, we investigated whether F9 fimbriae could induce a transcriptional response in model plant Arabidopsis thaliana, compared with flagella and another fimbrial type, E. coli common pilus (ECP), using DNA microarrays. F9 induced the differential expression of 435 genes, including genes involved in the plant defence response. The expression of F9 at environmentally relevant temperatures and its recognition of plant xyloglucan adds to the suite of adhesins EHEC has available to exploit the plant niche.

Extraction of lignocellulosic constituents from cow dung: preparation and characterisation of nanocellulose

Continuous growth of the livestock population over the years has led to the generation of huge livestock waste. Inadequate management of animal waste and its poor disposal poses a serious public health issue and also leads to environmental pollution. In the recent decade, the rational use of lignocellulosic biomass towards preparation of bioproducts such as biofuels and biotextile has come up as a promising alternative for the efficient utilisation of animal waste biomass. Hence, the current study is focused on the efficient utilisation of an abundant source of lignocellulosic constituents, i.e. cow dung by the extraction and estimation of cellulose, lignin, and hemicellulose, respectively by an optimised kraft pulping method. The extracted cellulose was evaluated for the degree of polymerisation and was further used for the preparation of nanocellulose which has a wide range of applications. Cellulose and nanocellulose so obtained were morphologically and spectroscopically characterised by SEM-EDX, CHNS elemental analysis, TEM, and FT-IR techniques. Further, nanocellulose was also evaluated for its physical properties such as crystallinity index and zeta potential, which revealed their good crystallinity and excellent particle stability profile. Hence, this study is an innovative approach towards the valorisation of cow dung waste biomass into useful biomaterial, i.e. nanocellulose.

Enzymatic production of xylooligosaccharide from date (Phoenix dactylifera L.) seed.

Date palm (phonix dactylifera L.) is an important tropical fruit growing in central and southern regions of Iran. Date seed is composed of cellulose, hemicellulose, and lignin, that make it an excellent candidate for xylooligosaccharide (XOS) production. In this study, two different protocols are used for the extraction of hemicellulose from date seeds. In the first protocol, hemicellulose (xylan1) was extracted by 2.25 M alkaline solution at room temperature for 24 hr. In the second protocol, date seed was treated with LCHTA (low concentration, 0.1 M, high temperature, 80°C, alkaline solution) for 3 hr, and thereafter, hemicellulose (xylan2) was extracted by 2.25 M alkaline solution at room temperature for 24 hr. The carbohydrate units of xylan1 and xylan2 were qualified and quantified by HPAEC‐ PAD. Side groups of xylan1 and xylan2 were detected by FTIR. In the next step, xylan1 and xylan2 were exposed to two commercial endoxylanases namely veron 191 and pentopan mono BG. Temperature, pH, time, and enzyme dosage of hydrolyzation were optimized to maximize XOS and minimize xylose. The results showed that the enzymes successfully hydrolyzed xylan2 and produced XOS, but cannot hydrolyze xylan1. Pentopan mono BG and veron 191 produced the highest amount of XOS after 4 (1.17 mmol/g) and 6 hr (1.13 mmol/g) of incubation, respectively. Conversion factors of xylan2 to XOS for pentopan mono BG and veron were 0.41 and 0.36, respectively. This study presence the possible prebiotic properties of date seed XOS and its application in functional foods.

Efficient process engineering for extraction of hemicellulose from corn fiber and its characterization

The present work, aims to extract hemicellulose from de-starched corn fiber (by-product of corn wet-milling industry) by using alkalis, combinations and hydrothermal treatments. The corn fiber was destarched by amylase and achieved 34% (w/w) maltose and 1.5% (w/w) glucose. Maximum yield of solubles from corn fiber via thermochemical treatment is 47% (w/w) in the liquid fraction. The compositional analysis of extracted solubles was rich in arabinoxylan, monosaccharides, ferulic acid and oligosaccharides. The characterization of extracted fraction were analysed by FTIR, SEM and HPLC techniques. The remaining insoluble fraction (cellulose) was 51.6% (w/w). Oligosaccharides rich liquor and the cellulose enrichment of the solid phase make corn fiber suitable as a prebiotic fiber in the food industry. The integrated process not only converted the fiber to valuable products like maltose, hemicellulose (hemicellulose B) and cellulose but, also a sustainable approach for utilization of starch industry processing by-products of corn.

Effect of microwave‐assisted alkali pre‐treatment on fractionation of pistachio shell and enzymatic hydrolysis of cellulose‐rich residues

AbstractBACKGROUNDPistachio shell is a lignocellulosic biomass with a high potential to be converted into chemicals, biopolymers, and biofuels. Alkaline pre‐treatment is an effective way to extract hemicellulose and increase the cellulose hydrolysis. However, there are some disadvantages to this process, such as a long processing time and the formation of high amounts of degradation products. Microwave irradiation can be used to enhance the effectiveness of alkaline treatment. In this study, microwave‐assisted alkali pre‐treatment (MAAP) was carried to fractionate pistachio shell into its valuable components (i.e., hemicellulose and cellulose), and the enzymatic hydrolysis of cellulose‐rich residues was performed to produce fermentable sugars.RESULTSThe MAAP conditions (microwave power, NaOH concentration, and pre‐treatment time) were studied and optimized by Box–Behnken design to obtain the highest hemicellulose and cellulose yields. Optimal pre‐treatment conditions were microwave power of 224 W, NaOH concentration of 1.96 N, and pre‐treatment time of 2.63 min. Under these conditions, the recoveries were 58.35% and 92.46% for hemicellulose and cellulose, respectively. Additionally, compositional analysis carried out on the solid and liquid fractions obtained from the pre‐treatments indicated that the main components in the liquid phases were xylooligosaccharides (XOS) and the solid phases were enriched in cellulose. MAAP enhanced the enzymatic hydrolysis yield, and a maximum glucan to glucose conversion yield of 82.67 mol% was obtained for the solid pre‐treated under optimum conditions.CONCLUSIONThe studied MAAP process could be an effective and viable option to extract hemicellulose from pistachio shell and increase the enzymatic digestibility of cellulose‐rich solid residues. © 2020 Society of Chemical Industry (SCI)

Development and optimization of hemicellulose extraction bioprocess from poppy (Papaver somniferum L.) stalks assisted by instant controlled pressure drop (DIC) pretreatment

Global efforts are being made to replace petroleum-based products with renewable biomass-based products through sustainable processes. Currently, hemicelluloses are of great interest in the framework of the biorefinery approach. This work is aimed to develop a hemicellulose extraction process by combining instant controlled pressure drop (DIC) and alkaline extraction methods and to optimize the process conditions. Opium poppy (Papaver somniferum L.) waste stalks are selected as the model lignocellulosic biomass. Response surface methodology (RSM) was used to determine the effects of DIC process variables with a significant influence on hemicellulose yield including; saturated steam pressure (2–5 bar), processing time (60–540 s) and moisture content (7–85%). Alkaline extraction process conditions covering alkaline (KOH) concentration (5–25%), extraction time (1–7 h) and precipitant volume (25–125 ml) were optimized to maximize the extraction yield and the sustainability of the process. Optimum process conditions were determined as 5 bar saturated steam pressure, 540 s processing time, 7% moisture content for DIC and 22.17% KOH, 7 h extraction time, 53.28 ml precipitant volume for alkaline extraction. Under the verified optimum conditions, 26.23 ± 0.04% hemicellulose extraction yield was reached. As a result, hemicellulose yield was increased by 49.7% with the co-current saving in the amount of KOH and the precipitant solution used, and shortening of the processing time. The destructive effect of DIC on the stalks was demonstrated by SEM analysis.

Synergistic Action of Alkalis Improve the Quality Hemicellulose Extraction from Sugarcane Bagasse for the Production of Xylooligosaccharides

The present study demonstrates an effective alkaline protocol for the extraction of quality hemicellulose using NaOH and NH4OH combination from sugarcane bagasse for the production of xylooligosaacharides (XOs). For achieving maximum recovery of hemicellulose, the statistical optimization technique was adapted, while considering alkali concentration and temperature, as important process parameters, for all of the alkaline tested protocols like individual or mixed alkalis. The comparative study exposed that mixed alkalis promoted higher recovery of hemicellulose (68% wt xylose), which is relatively higher (up to 1.3-times) than the individual alkali protocols, such that it contained predominantly the xylose (xyl/ara ratio was 3.94) in the form of xylan. In perception, the synergistic action of different alkalis (weak and strong bases) have strongly influenced the selective cleavage of lignin-carbohydrate linkages, thereby enabling the higher release of hemicellulose under the modest reaction conditions (10% alkali conc. and 120 °C). Moreover, the analytical characterization witnessed that it is composed of majorly xylose with less or no undesired residual biomass constituents, including lignin. Upon evaluating the resultant hemicelluloses for XOs production via acidic hydrolysis, the hemicellulose obtained through the mixed alkalis protocol exhibited exceptional, resulting in ~ 13% wt XOs yield with a high degree of polymerization (2–4 units); it is relatively ~ 2.8-times higher than the result of other hemicelluloses. In addition, the formation of gaseous ammonia during the reaction of the mixed alkalis could potentially contribute to the reduction of overall processing cost through recovery and reuse strategy during the large-scale XOs production.