Hemicellulose Yield Research Articles

Effects of peracetic acid delignification on hemicellulose extraction by dimethyl sulfoxide

Extracting high-purity and structurally intact hemicelluloses from lignocellulosic fibers is a prerequisite to reveal their structures and realize high-value utilization. Delignification is usually performed before hemicellulose extraction to break the covalent bonds between hemicelluloses and lignin for effective separations, but usually leads to toxic by-products and hemicellulose degradation. Peracetic acid (PAA) is an environmentally friendly oxidizing agent, which is more selective for delignification and has less effect on the primary structure of hemicelluloses. However, the yields and chemical structures of hemicelluloses extracted at different PAA delignification conditions are not clear, which greatly hinders its research and application. Consequently, the response surface methodology (RSM) was used in this study to optimize the process parameters of PAA delignification. With the increase of temperature or time, the yield of holocellulose decreases, and the hemicellulose yield increases first and then decreases. With the increase of delignification degree, the hemicellulose yield increases significantly. The degree of PAA delignification also has a significant effect on the chemical structures of extracted hemicelluloses; hemicellulose samples extracted from highly delignified holocelluloses have a higher xylose unit content, molecular weight (MW) and degree of substitution by acetyl groups (DSAc). The tert-butanol solvent exchange or ball milling treatments on holocelluloses significantly increase the hemicellulose yields, by avoiding the hornification and improving the accessibility of holocellulose. This study will provide theoretical and technical support for the efficient separation of hemicelluloses.

Biorefinery electrification of brewers’ spent grains using plasma bubbles for sustainable production of poly(3-hydroxybutyrate)

Biorefinery electrification could be implemented for sustainable refining of crude renewable resources eliminating the use of high temperatures and pressures, alkaline and acidic solutions and conventional solvents. A plasma bubble reactor using air as the feed gas was employed to enhance poly(3-hydroxybutyrate) (PHB) production from brewers’ spent grains (BSG) facilitating the fractionation of protein and lignin as value-added co-products. Plasma factors (voltage, pretreatment duration, duty cycle, initial solids concentration) were evaluated with the highest overall conversion yield of glucan and hemicellulose (73 %, 0.494 g sugars/gBSG) achieved for initial solids concentration of 150 g/L. The produced BSG hydrolysate led to higher PHB production efficiency (130 g/L total dry weight, 74.4 gPHB/L, 0.32 g/g yield, 2.64 g/L/h productivity) than conventional hydrolysates produced by enzymatic hydrolysis alone and enzymatic hydrolysis combined with hydrothermal treatment. The protein and lignin losses in the remaining BSG solids were 24.1 % and 29.2 % respectively. When renewable electricity is employed, the global warming potential was estimated at 0.59 kg CO2-eq per kgPHB and the abiotic depletion potential fossil at 11.12 MJ per kgPHB for PHB production based on plasma treated BSG. In the proposed biorefinery concept, 1 kg BSG could be converted into 147.6 g PHB with a solid fraction containing 137.4 g protein and 98.4 g lignin that could be subsequently fractionated as value-added co-products. The rationale of this study is to demonstrate that BSG plasma treatment can be used for the exploitation of the full potential of BSG for the production of PHB with improved environmental impact and minimal losses of protein and lignin.

Optimizing hemicelluloses pre-extraction in eucalyptus kraft pulping: A pathway towards enhancing pulp mill biorefineries

A critical pathway towards enhancing pulp mill biorefineries is to integrate the extraction and utilization of hemicelluloses into the pulping processes. Hence, an industrial pre-extraction strategy for hemicelluloses targeting eucalyptus kraft pulping process was developed. Alkaline solution or pulping white liquor was used to pre-extract hemicelluloses before the actual pulping process. The response surface methodology (RSM) technique was applied to investigate the most suitable conditions to maximize the yield of these hemicelluloses while simultaneously minimizing the damage to pulp yields and properties. Temperature (105 to 155 °C), alkali concentration (3 to 8%), sulfidity (20 to 30%) and retention time (19 to 221 min) were combined to evaluate their effects on hemicellulose yields and chemical structures. The optimal pre-extraction conditions identified in this work (5.75% NaOH concentration, 25% sulfidity at 135 °C for 60 min) successfully allowed recovering 4.8% of hemicelluloses (based on the wood dry mass) and limited damages to pulp yields and properties. The cellulose content in pulp can even be increased by about 10%. Hemicellulose emulsification properties were also evaluated, which were comparable to synthetic emulsifiers. This study provides an industrial pathway to effectively separate and utilize wood hemicelluloses from the pulping process, which has the potential to improve the economy and material utilization of pulp and paper mills.

Benzoic acid catalyzed production of xylose and xylooligosaccharides from poplar

The proficient synthesis of xylose and xylooligosaccharides (XOS) from lignocellulosic biomass proved to be a formidable undertaking, particularly in the absence of preliminary hemicellulose isolation. In this study, the potential of benzoic acid (BZA), a non-toxic and edible acidic catalyst, was assessed for the pretreatment of poplar in order to produce xylose and xylooligosaccharides (XOS). At low temperatures (< 160°C) or low acid concentrations (< 2%), the main product obtained from the depolymerization of hemicellulose was XOS, and no significant depolymerization occurred on a large scale. The results showed that the highest extraction yield of hemicellulose was 93.1% with 2% BZA at 160°C for 0.75 h, hemicellulose was mainly converted into xylose and XOS, with xylose accounting for 27.1% and XOS accounting for 46.7%. Meanwhile, the results of the process simulation of industrial energy consumption indicated that the amount of water added was the main factor affecting energy consumption in industrialization, followed by temperature. This study presented a promising approach for the industrial-scale manufacturing of xylose and XOS from poplar as a primary resource.

Green bio-based aprotic solvents for efficient fractionation of hemicellulose and targeted value addition of lignin

It is of great significance to inhibit the repolymerization of lignin when removing hemicellulose by acid pretreatment. Adding a lignin fragment scavenger is an effective method to inhibit its repolymerization. Here, the effect of a bio-based polar aprotic solvent, levulinic acid (Lev), and γ-valerolactone (GVL) coupled pretreatment system on the separation yield of poplar biomass components was investigated. The optimum pretreatment conditions were a Lev concentration was 7.0%, reaction temperature was 170 °C, pretreatment time was 60 min, and GVL concentration was 9.0%. The separation yield of hemicellulose was 84.54%, which was a 4.53% increase over that with Lev pretreatment. The retention yield of cellulose was 89.68%. In addition, the separation efficiency was significantly improved when the pretreatment time was reduced by 40 min. The reaggregation of lignin was suppressed under the condition of maximum hemicellulose separation. In the lignin samples the content of β-O-4 was as high as 47.81%. Simultaneously, the content of phenolic and aliphatic hydroxyl increased. The results revealed that Lev/GVL pretreatment had good hemicellulose separation selectivity and excellent lignin fragment removal efficiency. This provides a new strategy for suppressing adverse effects on the lignin structure in the efficient separation of hemicellulose in pretreatment.

STEPWISE EXTRACTION OF HEMICELLULOSES WITH WATER AND ALKALI FROM LARCH WOOD AND THEIR SUGAR COMPOSITIONS

The aim of the present study was to isolate hemicelluloses by stepwise extraction with water and alkali from larch (Larix principis-rupprechtiiMayr) sapwood and heartwood. Onewater-soluble arabinogalactan (AG) and three alkali-soluble hemicelluloses-arabinoglucuronoxylan (AGX), galactoglucomannan (GGM) and glucomannan (GM) were obtained. The yield of AG extracted with hot-water from larch heartwood was 7.57%, it was 17.96% in total of three alkali-extracted hemicelluloses. There was no significant difference in the yield of hemicelluloses from sapwood and heartwood. Monosaccharide compositions of thehemicelluloses were determined by high performance liquid chromatography after acid hydrolysis. The results showed that galactose and mannose were the main glycosyl units of hemicellulose, followed by xylose. Galactose mainly derived from AG, whereas mannose and xylose originated from alkali-extracted hemicelluloses.

Improving lactic acid yield of hemicellulose from garden garbage through pretreatment of a high solid loading coupled with semi-hydrolysis using low enzyme loading

Byproduct (acetate and ethanol) generation and carbon catabolite repression are two critical impediments to lactic acid production from the hemicellulose of lignocellulosic biomass. To reduce byproduct generations, acid pretreatment with high solid loading (solid–liquid ratio 1:7) of garden garbage was conducted. The byproduct yield was only 0.30 g/g during in the subsequent lactic acid fermentation from acid pretreatment liquid and 40.8% lower than that of low solid loading (0.48 g/g). Furthermore, semi-hydrolysis with low enzyme loading (10 FPU/g garden garbage cellulase) was conducted to regulate and reduce glucose concentration in the hydrolysate, thereby relieving carbon catabolite repression. During the lactic acid fermentation process, the xylose conversion rate was restored from 48.2% (glucose-oriented hydrolysis) to 85.7%, eventually achieving a 0.49 g/g lactic acid yield of hemicellulose. Additionally, RNA-seq revealed that semi-hydrolysis with low enzyme loading down-regulated the expression of ptsH and ccpA, thereby relieving carbon catabolite repression.

Pretreatment of moso bamboo with p-toluenesulfonic acid for the recovery and depolymerization of hemicellulose

Bamboo and its mechanical processing residues have broad prospects for high value-added utilization. In this research, p-toluenesulfonic acid was used for the pretreatment of bamboo to investigate the effects of extraction and depolymerization of hemicellulose. The response and behavior of changes of cell-wall chemical components were investigated after different solvent concentration, time, and temperature pretreatment. Results indicated that the maximum extraction yield of hemicellulose was 95.16 % with 5 % p-toluenesulfonic acid at 140 °C for 30 min. The depolymerized components of hemicellulose in the filtrate were mainly xylose and xylooligosaccharide, with xylobiose accounting for 30.77 %. The extraction of xylose from the filtrate reached a maximum of 90.16 % with 5 % p-toluenesulfonic acid at 150 °C for 30 min pretreatment. This research provided a potential strategy for the industrial production of xylose and xylooligosaccharide from bamboo and for the future conversion and utilization.

Boosting VFAs production during the anaerobic acidification of lignocellulose waste pulp and paper mill excess sludge: Ultrasonic pretreatment and inoculating rumen microorganisms

Ultrasonic pretreatment combined rumen microorganisms (RM) anaerobic hydrolysis was used as a novel method to boost volatile fatty acids (VFAs) production from lignocellulose waste pulp and paper mill excess sludge (PPES). To investigate the effect of ultrasonic on PPES degradation, various ultrasonic power levels and treatment time were used to treat PPES. The findings showed that ultrasonic pretreatment breaks the structure of PPES distinctly and significantly contributes to promoting PPES degradation. Under ultrasonic power level of 540 W and treatment time of 50 min conditions, the production of soluble chemical oxygen demand (SCOD), ammonia nitrogen (NH4+-N), reducing sugar, and soluble protein was 36.9, 16.9, 29.2, and 26.8 times of control-1, respectively. In the following RM anaerobic acidification experiment, VFAs production of PPES after ultrasonic treatment increased by 92 % compared to that of PPES without ultrasonic treatment and were much higher than that of the control-2 group without inoculating RM. During the fermentation stage, the degradation yield of cellulose, hemicellulose and lignin were 40.35 %, 58.35 % and 16.49 %, respectively. These results demonstrated that ultrasonic-RM treatment could improve the efficiency of the anaerobic acidification process and VFAs production and RM had a strong effect on degradation of hemicellulose and cellulose. In addition, Illumina MiSeq sequencing showed that the number of microbial species decreased, and the dominant flora changed.

Efficient separation of eucalyptus hemicellulose and improvement of the stability of the remaining components by 1-amino-2-naphthol-4-sulfonic acid pretreatment

High selectivity of hemicellulose separation is difficult to achieve using organic acid pretreatment. This is attributed to the depolymerization and polycondensation of lignin, which is accompanied by the separation of hemicellulose. In this study, the separation of eucalyptus components was studied by 1-amino-2-naphthol-4-sulfonic acid (ns-A) pretreatment. An organic acid concentration of 9% at a pretreatment temperature of 170 °C performed for 80 min was determined as the optimum condition for ns-A pretreatment. The separation yield of hemicellulose increased to 82.76% compared with that of p-toluenesulfonic acid pretreatment. The separation yield of lignin decreased from 30.20% to 8.43%. The surface coverage of lignin increased from 0.70% to 0.83%. Furthermore, the recovery yield of the organic acids in the ns-A pretreatment process was 91%. The ns-A-pretreated acid solution provided stable, efficient separation within six reuse cycles. Lignin in eucalyptus was found to be rich in aliphatic hydroxyl groups and guaiacyl-syringyl units. Therefore, the depolymerization and polycondensation of lignin was inhibited while efficiently separating hemicellulose during ns-A pretreatment. This study provides a new method for the efficient separation of lignocellulosic biomass.

Superior separation of hemicellulose-derived sugars from eucalyptus with tropic acid pretreatment

Organic acid pretreatments can efficiently separate biomass-based hemicellulose and selectively produce hemicellulose-derived sugars. In this study, hemicellulose is separation as xylose, oligosaccharides in the tropic acid-catalyzed hydrothermal pretreatment of eucalyptus. The maximum yield of hemicellulose-derived sugars (85.78 %) with 71.25 % xylose selectivity (based on the total xylose in raw material) was achieved in the hydrolysate under optimal conditions (5 % TA, 160 ℃, 80 min). The yield of hemicellulose-derived sugar and the separation yield of hemicellulose increased by 11.06 % and 11.45 % compared with glycolic acid pretreatment in the similar severity factor. The separation yield of cellulose and lignin was decreased by 4.23 % and 0.98 %, respectively. This resulted in residual solids with higher biological stability (higher fiber crystallinity index, higher thermal stability, and higher lignin content). Therefore, higher hemicellulose separation selectivity and rich hemicellulose-derived sugars were obtained using TA pretreatment. The work would bring up a new method for biomass refining.

Анализ возможностей извлечения органических соединений пивной дробины различными способами

Brewer's spent grain is a brewing industry waste product that contains various valuable biologically active substances. However, polymers can complicate their extraction. This article focuses on innovative extraction methods, including sustainable deep processing that destroys the internal structures of plant matrix. The research objective was to review publications on the sustainable brewer's spent grain processing as a source of secondary raw materials and plant matrix organic compounds.&#x0D; The study featured the last 5–10 years of foreign and domestic analytical and technical publications on grain structure and extraction methods.&#x0D; Unlike the traditional acidic, alkaline, and enzymatic methods of grain processing, physical and mechanical methods aim at extracting biogenic peptides, phenolic compounds, and fatty acids. The nature of the processing depends on the type of the extracted compound. Thus, for the extraction of reducing compounds intended for sorption, exposure to high temperatures (≥ 150°C) is the most effective method. A combined treatment with acids or alkalis of the cellulose-lignin complex makes it possible to achieve a 76.2% yield of hemicelluloses. Acid hydrolysis of arabinoxylans is effective at 120–160°C. Alkaline hydrolysis combined with physical treatment makes it possible to reach 60% of arabinoxylans in a mix with phenolic compounds. When extracting nitrogen-containing, phenolic, and lipid compounds, the degree of grinding of the biomaterial and the organic solvent is of great importance. The optimal degree makes it possible to preserve the spatial structure while maintaining a high yield (86%) of organic compounds. Ultrafiltration concentrates the isolated biogenic compound and preserves its activity with a high yield of up to 95%.&#x0D; The analysis proved that the brewer's spent grain processing can be both feasible and environmentally friendly. It produces a high yield of pure organic compounds, e.g., peptides, phenolic compounds, fatty acids, etc.

Efficient Recovery of Lignin and Hemicelluloses from Kraft Black Liquor

Black liquor (BL) from kraft pulping industries contains a large fraction of lignin and hemicelluloses and their efficient separation can open up new possibilities for integrated biorefineries. In this work, lignin and hemicelluloses were separated from BL and concentrated BL (obtained by ultrafiltration), by precipitation using acidification and antisolvent precipitation method, respectively. For lignin precipitation, different organic acids, namely acetic, lactic and citric acid, were used and the yield and purity of the extracted lignin were compared with the lignin precipitated using inorganic acids, namely sulphuric and phosphoric acid. Among the organic acids, the highest yield of lignin (57.2%) was obtained by lactic acid, but the extract also contained the highest levels of inorganic impurities (9.2%). The extract obtained from acetic acid contained lower inorganic impurities and the lignin yield was 48.1%. The hemicellulose was extracted from BL liquor that was concentrated using the ZnObased PES mixed matrix ultrafiltration membrane, which was started by first separating lignin (at pH 3.5, 4 and 4.5) from it. The supernatants from the lignin precipitation process were used as a source of hemicellulose and this was precipitated by using acetone as an antisolvent. The highest hemicellulose yield (54.4%) was obtained from the supernatant with the lowest lignin content and highest acetone to supernatant ratio.&#x0D; Keywords: acidification, antisolvent precipitation, hemicelluloses, kraft black liquor, lignin

High-efficiency separation of hemicellulose from bamboo by one-step freeze–thaw-assisted alkali treatment

The selectivity of alkali treatment (AT) for hemicellulose separation is reduced due to the alkali solubility of lignin. It was improved using freeze–thaw-assisted alkaline treatment (FT/AT). In this study, bamboo hemicellulose was separated via a one-step freeze–thaw-assisted alkali treatment (OFT/AT). The effects of freezing temperature, freezing time, alkali concentration, and treatment time on bamboo components were studied. The separation yield of hemicellulose was 73.26%, compared to 64.00% using conventional FT/AT. The separation of lignin and cellulose was inhibited as alkali concentration decreased from 7.0% to 5.0%. The extraction yield of hemicellulose increased from 46.35% to 56.12%. Structural analysis of extracted hemicellulose revealed the effective inhibition of the breakage of the xylose backbone and arabinose side chain of hemicellulose. This indicated that the molecular structure of extracted hemicellulose was relatively complete. It provides theoretical support for the efficient separation of hemicellulose by AT.

High-Efficiency and High-Quality Extraction of Hemicellulose of Bamboo by Freeze-Thaw Assisted Two-Step Alkali Treatment.

Hemicellulose is a major component of the complex biomass recalcitrance structure of fiber cell walls. Even though biomass recalcitrance protects plants, it affects the effective utilization of lignocellulosic biomass resources. Therefore, the separation and extraction of hemicellulose is very important. In this study, an improved two-step alkali pretreatment method was proposed to separate hemicellulose efficiently. Firstly, 16.61% hemicellulose was extracted from bamboo by the weak alkali treatment. Then, the physical freezing and the alkali treatment were carried out by freezing at −20 °C for 12.0 h and thawing at room temperature, heating to 80 °C, and treating with 5.0% sodium hydroxide for 90 min; the extraction yield of hemicellulose reached 73.93%. The total extraction yield of the two steps was 90.54%, and the molecular weight and purity reached 44,865 g·mol–1 and 89.60%, respectively. It provides a new method for breaking the biomass recalcitrance of wood fiber resources and effectively extracting hemicellulose.

Isolation and Enzymatic Degradation of Hemicellulose from Corncobs Waste

Corncobs are rich in hemicellulose, which has very important applications in the food industry and biofuels. Hemicellulose is a heteropolysacharide which contains hexosan such as glucan, mannan, galactan and pentosan such as xylan and arabinan. The aims of this research are determining the optimum condition of hemicellulose isolation and identifying enzymatic degradation products of hemicellulose. Hemicellulose is extracted from corn cobs using various NaOH concentrations and extraction times. Acetic acid was added to the mixture after hemicellulose A reflux process, whereas hemicellulose B was precipitated with ethanol 96%. Enzymatic hydrolysis is carried out using xylanolytic enzyme from a recombinant of E. coli DH5α. The yield of hemicellulose is nearly 64.74% (w/w) using NaOH 4 M for 2 h of extraction time. Based on High Performance Liquid Chromatography data indicating that the enzymatic hydrolysis products of hemicellulose A are xylose and arabinose. While xylose, arabinose, and xylooligosaccharide are hemicellulose B and unextracted hemicellulose hydrolysis products.

Hemicellulose Films from Curaua Fibers (Ananas erectifolius): Extraction and Thermal and Mechanical Characterization.

With growing environmental concerns over synthetic polymers, natural polymeric materials, such as hemicellulose, are considered a good sustainable alternative. Curaua fibers could be an excellent source of biopolymer as they have a relatively high hemicellulose content (15 wt%) and only a small amount of lignin (7 wt%). In this work, hemicellulose was extracted by an alkaline medium using KOH and the influence of the alkali concentration, temperature, and time was studied. A hemicellulose film was produced by water casting and its mechanical, thermal, and morphological properties were characterized. The results show that the best method, which resulted in the highest hemicellulose yield and lowest contamination from lignin, was using 10% (w/v) KOH concentration, 25 °C, and time of 3 h. The hemicellulose film exhibited better thermal stability and elongation at break than other polymeric films. It also exhibited lower rigidity and higher flexibility than other biodegradable polymers, including polylactic acid (PLA) and polyhydroxybutyrate (PHB).

Optimization of hemicellulose recovery from black liquor using ZnO/PES ultrafiltration membranes in crossflow mode

Black liquor, one of the by-products of pulp and paper industry, is an underexplored resource with great potential for the recovery of valuable biopolymers such as lignin and hemicelluloses. In this work, the hemicellulose was recovered from this liquor, containing 17 % of total dissolved solids, using ZnO/polyethersulfone ultrafiltration membrane. The hemicellulose was concentrated into the retentate stream while lignin was permeated through these membranes. The effects of transmembrane pressure (1 to 4 bar), time (up to 8 h) and crossflow velocity (0.1 and 0.2 m/s) were studied for ultrafiltration process operating in crossflow mode. The highest rejection of hemicellulose was achieved up to 90.7 ± 1.9 % at 4 bar. At 3 bar, the yield of hemicellulose was ≈ 90 % and 84 % for the volume reduction up to 60 % and 78 %, respectively. Mathematical modeling was applied to analyze the membrane fouling mechanism responsible for the flux reduction during filtration at constant pressure, as well as to predict the changes in hemicellulose and lignin concentration during the filtration process.

Effects of ultrasonic-assisted alkaline pretreatment on xylose production from pineapple peel waste

The pineapple industry generates large amounts of unusable waste (peel and core) with adverse environmental impacts. This experimental study aims to systemize the potential of ultrasonic-assisted alkaline pretreatment for xylose production from pineapple peel waste. The best condition for single alkaline pretreatment (1 % NaOH w/v, 100 °C, 60 min) has obtained hemicellulose, cellulose, and lignin composition at 34.80 %, 32.16 %, and 8.66 %, respectively, retained in the biomass. Meanwhile, a combination of alkaline (1 % NaOH, w/v) and ultrasonic (frequency 40 kHz, 45 min) pretreatment has obtained the percentage yield of hemicellulose and lignin at 51.15 % and 7.15 %, respectively. Both single alkaline and ultrasonic-assisted alkaline pretreated samples were subsequently hydrolyzed with 2 % H2SO4 (w/v). After acid hydrolysis for 30 min, the maximum xylose concentration of 48.85 g.L-1 was achieved by using ultrasonic-assisted alkaline pretreatment, while single alkaline pretreatment contributed to the lowest yield of xylose (37.11 g.L-1). It is shown that the ultrasonic-assisted alkaline treatment is more favorable than single alkaline pretreatment as it can produce high xylose concentration after the subsequent hydrolysis. These results indicated that ultrasonic-assisted alkaline pretreatment and its subsequent acid hydrolysis were appropriate for producing xylose from pineapple peel waste.

Optimasi Suhu dan Waktu Proses Delignifikasi pada Isolasi Selulosa dari Tongkol Jagung

This study aims to optimize the temperature and time of the delignification process to isolate cellulose from corn cobs. The research was carried out in stages, namely preparing corn cob powder samples and the delignification process. Statistical regression modeling and optimization of the temperature and time of the delignification process used the response surface (RSM) methodology. Central Composite Design (CCD) was used for experimental design and analysis of the effect of temperature and time of the delignification process on lignin, cellulose, hemicellulose, and fiber yields. The optimum process conditions were determined using the desirability method. The analysis of the diversity of the quadratic polynomial model shows that the temperature and time of the deligninification process significantly affect changes in the characteristics of lignin, cellulose, hemicellulose, and fiber yields. The optimal condition of the corncob fiber delignification process was obtained at a temperature of 100.38? for 79.17 minutes. It produced the characteristics of delignified fiber with lignin, cellulose, hemicellulose, and yields of 6.47%, 73.73%, 5, respectively. 39% and 57.76% w/w. The optimization model is valid with a desirability value of 0.71. Thus, the temperature and time optimization model of the delignification process can be applied in real conditions to produce delignified corncob fiber with optimum characteristics.