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Sugar beet pulp (SBP) samples were subjected to a two-step non-isothermal autohydrolysis process in order to obtain mixtures enriched in oligogalacturonides (OGalA) and arabinooligosaccharides (AOS) in separate streams. Operating at a maximum temperature of 130 °C, mixtures containing up to 30.4% oven-dry basis (o.d.b.) of OGalA with an OGalA/AOS ratio of 5.0 g/g were obtained during the first stage. Then, the treated solids were subjected to a second treatment at temperatures in the range 160–175 °C. When those solids were treated up to 175 °C, a mixture mainly made up of AOS (37.5% o.d.b.) with an AOS/OGalA ratio of 3.91 g/g was obtained as an effluent from the reactor. In order to increase their purity, both streams were then subjected to different refining steps. A product enriched in highly methylated and partially acetylated OGalA (42.5% o.d.b., degree of methylation (DM) = 69.2% mol/mol and degree of acetylation (DA) = 36.4% mol/mol), containing 17.2% o.d.b. of non-volatile non-identified compounds, was obtained by membrane filtration of the first-stage liquors, whereas a second one, mainly made up of AOS and galactooligosaccharides (GalOS) (55.0% AOS o.d.b., 13.8% GalOS o.d.b., and 13.3% non-volatile non-identified compounds, o.d.b.), was manufactured after an ion exchange treatment followed by membrane filtration of the second-stage liquors. This strategy was demonstrated to be a suitable and scalable alternative for the separate production of refined mixtures rich in OGalA or neutral pectic-oligosaccharides. Both types of products can result in different effects on the intestinal microbiota: AOS and GalOS show a significant bifidogenic effect and they could be consumed alone or combined with selected probiotic strains of Bifidobacteria for improving an unbalanced microbiota, whereas OGalA has been demonstrated to have a variety of biological properties and can promote the growing of some bacteria such as Faecalibacterium prausnitzii, a butyrate-producing microorganism underrepresented in patients with active IBD and infectious colitis. [ABSTRACT FROM AUTHOR]

This preliminary study investigated an environmentally friendly method for fabricating cellulose-rich dissolving pulp from Oil Palm (Elaeis guineensis) Trunk (VBOPT) fibre. This method encompassed an autohydrolysis pretreatment followed by soda pulping procedures. The impact of autohydrolysis pretreatment on the separation of lignocellulosic components was scrutinised to facilitate the production of chemical cellulose. Autohydrolysis was performed on VBOPT fibre for 60 min at temperatures ranging from 140°C to 160°C, maintaining a solid-to-liquid ratio of 1:8. The yield of the prehydrolysed OPT varied between 73.5% and 91.5%. The chemical composition of the prehydrolysed VBOPT fibre comprised 70.6-80.0% holocellulose, 63.7-87.1% α-cellulose, 7.4-10.9% ß-cellulose, 5.5-25.4% γ-cellulose, and 21.5-26.6% lignin. The prehydrolysed OPT was subsequently subjected to alkaline pulping under fixed conditions: a temperature of 160°C, a treatment time of 60 min, a chemical charge of 25%, and a solid-to-liquid ratio of 1:6. The resultant pulp exhibited properties such as a screening yield of 41.5-46.4%, a kappa number of 4.5-9.6, and α, β, and γ cellulose content of 89.4-98.1%, 1.5-5.3%, and 0.4-6.9%, respectively. Based on the chemical composition of the OPT biomass before and after pretreatment, as well as post-alkaline cooking, the autohydrolysis pretreatment was determined to significantly influence the resultant pulp. A more comprehensive understanding of the interdependence of autohydrolysis and pulping processes can be achieved by executing an optimisation study focusing on key parameters of autohydrolysis and pulping, including temperature, treatment duration, and chemical charge. [ABSTRACT FROM AUTHOR]

Pretreatment is an essential step for breaking the recalcitrant structure of lignocellulosic biomass and allowing conversion to high-value-added chemicals. In this study, coconut fiber was subjected to three pretreatment methods to compare their impacts on the biomass's structural characteristics and their efficiency in fractionating the biomass. This comparative approach was conducted to identify mild biomass pretreatment conditions that efficiently extract lignin and recover cellulose-rich pulp for the production of bioproducts. To this end, autohydrolysis, alkaline, and organosolv pretreatments were performed under different experimental conditions, and the physicochemical properties of the samples were evaluated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and chemical characterization of the cellulose, hemicellulose, and lignin fractions. Therefore, efficient experimental conditions were identified to pretreat coconut fibers with an extended understanding of the methods to process lignocellulose. Great delignification efficiency and pulp yield were obtained with organosolv > alkaline extraction > autohydrolysis under the selected conditions of 2 h at 185 °C in the presence of a catalyst, namely, 0.5 M NaOH, for 2 h at 55 °C and 20 min at 195 °C, respectively. FT-IR revealed a predominance of hydroxyl groups in fibers obtained from alkaline and organosolv pretreatment, showing higher lignin degradation and cellulose concentration in these samples. TGA revealed mass loss curves with similar behaviors but different patterns and intensities, and MVE analysis showed differences on the surfaces of each sample. The comparison of experimental parameters allowed the identification of suitable conditions for each extraction method, and structural analyses identified the specific characteristics of the fibers that could be obtained according to the method used. Therefore, the results are of great importance for developing sustainable and effective industrial processes. [ABSTRACT FROM AUTHOR]

Elephant grass is a promising lignocellulosic biomass for use in biorefineries due to its composition and productivity. To enhance the use of elephant grass (Pennisetum purpureum Schum.) as a raw material for the production of fermentable sugars, two different hydrothermal pretreatment methodologies were studied, using liquid hot water and saturated steam. Hydrothermal pretreatments were carried out according to a central composite design, varying the time (1–12 min) and temperature (170–220 °C) of the processes. Solid fractions were subjected to hydrolysis using the enzymatic complex produced by Pennicilium echinulatum. Both methodologies tested showed a strong positive linear correlation between the severity factor [logRo] of the pretreatments and the removal of hemicellulose, allowing a high recovery of cellulose in the solid fraction. In pretreatments with an intermediate severity factor, between 2.87 and 3.88, the liquid hot water pretreatment improved the enzymatic hydrolysis yield, in addition to presenting the best fractionation of hemicellulose and total glucose yield. However, at pretreatment severity factors equal to or greater than 4.30, saturated steam pretreatment allowed a greater increase in hydrolysis yield. The maximum enzymatic hydrolysis yield was 65.6 mol%, obtained in saturated steam pretreatment at 220 °C for 6.5 min, being 147 mol% higher than the yield of untreated elephant grass. Mathematical models describing the enzymatic hydrolysis yield as a function of time and temperature used in each pretreatment methodology are proposed. [ABSTRACT FROM AUTHOR]

This work presents a new sequential approach to the sugarcane bagasse autohydrolysis process in a way that the liquor from the previous reaction was reused in the next one, and the makeup water for the next batch was used to wash the solid fraction before being added to the liquor in the next batch. This approach was suggested first as a way of reducing the water usage in the process, and second as a way of concentrating the liquor in any interesting component, working with the possibility of losing efficiency towards the glucose production through a cellulose loss to the liquor or enzymatic efficiency loss from a higher inhibitor concentration. Two sets of five sequential batches were performed: one washing the solids with the makeup water prior to the enzymatic step (Set 2), and the other one without the washing step (Set 1), looking forward to the effects of the water reuse over the glucose production and the liquor composition. Autohydrolysis pretreatment removed most of the hemicellulose (∼94 %), with liquor recycling improving its removal until the third batch and stabilizing after that. Although the washing step showed little impact on the composition of the solids, it was determinant to the success of the enzymatic hydrolysis, since it was possible to maintain the cellulose to glucose yield around 53% throughout the batches. There was a 64 % reduction in the water used in the sequential reactions without interfering in the glucose production, which indicates that the proposed strategy could be successfully used to reduce costs and environmental impacts associated with the pretreatment of lignocellulosic biomass.

Effective separation of various components in biomass is critical for biorefinery. Autohydrolysis is a commercialized unit operation to remove hemicelluloses, such as xylan, in producing high‐quality cellulose (the so‐called dissolving pulp) in the pre‐hydrolysis kraft process. In the present study, the autohydrolysis of eucalyptus woodchips was investigated for the purpose of producing dissolving pulps, with a focus on the production of cellulose acetate grade dissolving pulp. First, the effects of liquid‐to‐solid ratio, maximum temperature, and time on hemicelluloses removal were comprehensively studied, and the total xylose saccharides concentration and total xylose saccharides yield were determined as a function of the P factor and log(Ro). The three‐variable Box–Behnken design of the response surface methodology was followed to optimize the autohydrolysis conditions, aiming to achieving the maximum removal of xylan. The as‐obtained optimal conditions were: liquid‐to‐solid ratio of 5.5 mL · g−1, maximum temperature of 165°C, and time of 120 min, with its P factor of 867 h and log(Ro) of 4.03. Under these conditions, the total xylose saccharides concentration was 16.43 g · L−1. Furthermore, the autohydrolysis yield was investigated. The results showed that the purity of as‐prepared cellulose substrate as a result of autohydrolysis at a P factor of 867 h (log(Ro) of 4.03) can meet the stringent requirement of cellulose acetate grade dissolving pulp. Furthermore, the pre‐hydrolysis liquor compositions were compared between the typical autohydrolysis conditions for rayon grade dissolving pulp (a P factor of 690 h and log(Ro) of 3.91) and the optimal conditions (a P factor of 867 h and log(Ro) of 4.03). [ABSTRACT FROM AUTHOR]

Oil palm empty fruit bunch (EFB) as the main lignocellulosic residue from the oil palm industry serves as suitable feedstock for enzymatic saccharification, yielding fermentable sugars. Due to complex inter-association between hemicellulose, cellulose and lignin within EFB lignocellulosic matrix, different saturated steam conditions at 140-230 °C, 0.3-2.3 MPa was chosen as a pretreatment strategy, targeted to hydrolyze hemicellulose and reduce crystallinity of cellulose to enhance enzymatic saccharification which need no chemical requirement and potential for energy recovery. As a result, SEM analysis of EFB morphology indicated that the enhanced silica body removal from 190-230 °C of saturated steam pretreatment correspondingly led to substantial 82% removal of hemicellulose. Consequently, enzymatic saccharification yielded between 0.621-0.637 g glucose per g EFB, equivalent to 93-95% of cellulose saccharification by Acremonium cellulase on EFB treated with saturated steam at 210-230 °C. Notably, a short duration pretreatment of EFB at 210 °C for 2 min was proved sufficient for high fermentable sugar production. The potential energy estimated for employing saturated steam pretreatment of EFB in a palm oil mill was sufficient by 2.2 x 1012 kJ/year. [ABSTRACT FROM AUTHOR]

Pork represents a major fraction of the meat consumed worldwide but only 30% of the blood generated in slaughterhouses is re-used as raw material for food and feed. Innovative technologies and efficient processing strategies capable of generating added-value products from it are now attracting attention. In this study, the hydrolysis of porcine coagulated blood using sub-critical solvent extraction was investigated. Biomass was hydrolyzed using different temperatures (120–210 °C), applying only water (sub-critical water; SCW) or water with a low concentration of alkali (0.1 mol L−1 NaOH) and different reaction times (30–90 min). Resultant hydrolysates were analyzed for crude and soluble protein, peptide profile, and bioactivity by combining protein quantification, antioxidant activity, and fast protein liquid chromatography measurements. Results showed that increasing temperature increases the degree of hydrolysis and that the addition of NaOH enhances the solubilization of peptides with high molecular weights. Also, hydrolysates showed interesting antioxidant activity, being 60 min the time of reaction with best antioxidant activity. Nevertheless, using only water (SCW) as solvent, without chemical additives, allows the delivering of interesting protein-based bioactive fractions. Sub-critical solvent treatment of porcine blood resulted in added-value fractions with potential bioactivities through a simple and environmentally friendly process. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

When optimizing the process parameters of the acidic ethanolic organosolv process, the aim is usually to maximize the delignification and/or lignin purity. However, process parameters such as temperature, time, ethanol and catalyst concentration, respectively, can also be used to vary the structural properties of the obtained organosolv lignin, including the molecular weight and the ratio of aliphatic versus phenolic hydroxyl groups, among others. This review particularly focuses on these influencing factors and establishes a trend analysis between the variation of the process parameters and the effect on lignin structure. Especially when larger data sets are available, as for process temperature and time, correlations between the distribution of depolymerization and condensation reactions are found, which allow direct conclusions on the proportion of lignin's structural features, independent of the diversity of the biomass used. The newfound insights gained from this review can be used to tailor organosolv lignins isolated for a specific application. [ABSTRACT FROM AUTHOR]

Rapid cellular uptake of synthetic molecules remains a challenge, and the motif frequently employed to generate prodrugs, succinic ester, unfortunately lowers the efficacy of the desired drugs due to their slow ester hydrolysis and low cell entry. Here we show that succinic ester‐containing diglycine drastically boosts the cellular uptake of supramolecular assemblies or prodrugs. Specifically, autohydrolysis of the diglycine‐activated succinic esters turns the nanofibers of the conjugates of succinic ester and self‐assembling motif into nanoparticles for fast cellular uptake. The autohydrolysis of diglycine‐activated succinic esters and drug conjugates also restores the efficacy of the drugs. 2D nuclear magnetic resonance (NMR) suggests that a "U‐turn" of diglycine favors intramolecular hydrolysis of diglycine‐activated succinic esters to promote autohydrolysis. As an example of rapid autohydrolysis of diglycine‐activated succinic esters for instant cellular uptake, this work illustrates a nonenzymatic bond cleavage approach to develop effective therapeutics for intracellular targeting. [ABSTRACT FROM AUTHOR]

Rockrose lignocellulosic residues (RR) were selectively fractionated for hemicellulose separation using autohydrolysis, followed by an alkaline treatment to solubilize the lignin. The cellulose-enriched solids were used to study the effect of solid loading (SL: 2–10%) and enzyme dosage (ED: 6.34–23.66 FPU/g dry biomass) on saccharification using a Doehlert experimental design, followed by fermentation with the metabolic engineered Escherichia coli strain JU15 to produce D-lactic acid (DLA). Pretreatment increased glucan content and enzymatic digestibility up to 84%. A significant positive effect of SL and ED was found for glucose production, but SL negatively impacted glucose yield. DLA concentrations and productivity varied from 8.85 to 32.98 g/L and 1.11 to 2.17 g/(Lh), respectively. Overall process efficiency strongly depended on saccharification yield and varied from 33 to 71%. These results indicate that sequential autohydrolysis, delignification, and fermentation of RR may be a potential relevant strategy for D-lactic production in the biorefinery framework. [ABSTRACT FROM AUTHOR]

Copyright of Chemistry & Industry of Forest Products is the property of Chemistry & Industry of Forest Products Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study proposes an efficient strategy for co-producing high-value-added xylooligosaccharides (XOS) and humic-like acid (HLA) from vinegar residue based on two-step hydrothermal pretreatments. During the first-step hydrothermal pretreatment (170 °C, 50 min), 29.1% of XOS (X2-X6) was obtained. The XOS yield was further improved to 36.2% with endoxylanase hydrolysis, thereby increasing the value of (X2-X4)/XOS from 0.8 to 1.0. Subsequently, the second-step hydrothermal pretreatment was investigated to produce HLA from the solid residue of the first-step hydrothermal pretreatment. The highest HLA yield was 15.3% in the presence of 0.6 mol/L of KOH at 210 °C for 13 h. In addition, 31.7% of hydrochar by-product was obtained. The mass balance results showed that 1000 g of vinegar residue produced 67.9 g of XOS, 91.6 g of HLA, and 189.5 g of hydrochar. Therefore, this study provides a promising pathway for comprehensive use of lignocellulosic biomass in producing XOS and HLA. [ABSTRACT FROM AUTHOR]

Agro-industrial and food waste generation are increasing and alternatives are necessary for better use of these biomasses, such as conversion by liquid hot water (LHW), due to environmental and economic advantages. Moreover, it could be an alternative for the treatment of lignocellulosic biomass to produce xylooligosaccharides (XOS) and other value-added products. This study evaluated the production of XOS via LHW of industrial fruit and food waste. The application of LHW treatment showed a maximum of 32.60% XOS and 5.07% of xylose with banana peel residue, 8.21% of XOS and 1.99% of xylose with guava bagasse, 67.01% XOS and 4.02% xylose with orange bagasse, and 33.42% XOS and 2.56% xylose with restaurant residue. The results showed that the ideal conditions to obtain XOS are by using a high temperature and a low reaction time (160 °C and 15 min) for banana peel residue, a high temperature and medium time (172.43 °C and 35 min) for guava bagasse, a medium temperature and time for orange bagasse (130 °C and 35 min), and for restaurant waste, a medium temperature and a low reaction time (130 °C and 6.72 min). The best residue was orange bagasse with potential XOS production of 208 kg per ton of the material. This study determined LHW conditions that maximized XOS production with a low amount of xylose and degradation products, probably with no need for purification. However, attention is needed for the extractives to be solubilized with the LHW treatment of industrial fruit and food waste. [ABSTRACT FROM AUTHOR]

Seaweed contains a variety of bioactive compounds; the most abundant of them are polysaccharides, which have significant biological and chemical importance. Although algal polysaccharides, especially the sulfated polysaccharides, have great potential in the pharmaceutical, medical and cosmeceutical sectors, the large molecular size often limits their industrial applications. The current study aims to determine the bioactivities of degraded red algal polysaccharides by several in vitro experiments. The molecular weight was determined by size-exclusion chromatography (SEC), and the structure was confirmed by FTIR and NMR. In comparison to the original furcellaran, the furcellaran with lower molecular weight had higher OH scavenging activities. The reduction in molecular weight of the sulfated polysaccharides resulted in a significant decrease in anticoagulant activities. Tyrosinase inhibition improved 2.5 times for hydrolyzed furcellaran. The alamarBlue assay was used to determine the effects of different Mw of furcellaran, κ-carrageenan and ι-carrageenan on the cell viability of RAW264.7, HDF and HaCaT cell lines. It was found that hydrolyzed κ-carrageenan and ι-carrageenan enhanced cell proliferation and improved wound healing, whereas hydrolyzed furcellaran did not affect cell proliferation in any of the cell lines. Nitric oxide (NO) production decreased sequentially as the Mw of the polysaccharides decreased, which indicates that hydrolyzed κ-Carrageenan, ι-carrageenan and furcellaran have the potential to treat inflammatory disease. These findings suggested that the bioactivities of polysaccharides were highly dependent on their Mw, and the hydrolyzed carrageenans could be used in new drug development as well as cosmeceutical applications. [ABSTRACT FROM AUTHOR]

Cellulose and hemicellulose (xylans and mannans) are biopolymers present in plant biomass that can be bio-converted to ethanol. The challenge of hemicellulose fraction utilization for this process is its heterogeneous polymeric nature and low fermentability, resulting in wastage. However, this fraction contains mannan polysaccharides which can be converted using appropriate pretreatments before fermentation. This work was designed to produce bioethanol from pretreated mannan substrates that are abundant in our local environment. Mannan substrates palm kernel cake (PKC) and copra meal (CM) were pretreated with alkali, autohydrolysis and acid, followed by enzymatic hydrolysis using the mannan-degrading enzymes (MDES) at 10% (v/w) optimum enzyme loading. The hydrolysates were fermented to ethanol using Saccharomyces cerevisiae SCPW17 and results compared with theoretical values. Autohydrolysis gave the highest reducing sugar concentrations of 0.68±0.02 g/L (PKC) and 0.64±0.02 g/L (CM). Hydrolysis of substrates with a combination of MDEs gave the highest sugar yield of 81.7±1.36% (PKC) and 88.5±0.53% (CM). Ethanol concentrations of 4.1±0.032 and 4.9±0.094 g/L were produced within 36–48 h of simultaneous saccharification and fermentation of PKC and CM, respectively. Highest ethanol yield (g/g) of 0.45±0.005 (PKC) and 0.47±0.02 (CM) at 20% (w/v) substrate concentration was significantly higher than yields at 15% and 25% (w/v) for both substrates and comparable to the estimated 0.51 g/g theoretical yield from lignocellulose substrates. PKC and CM are viable substrates for bioethanol production because their ethanol yield compared favourably to theoretical value. [ABSTRACT FROM AUTHOR]

Seaweed derived biostimulants are gaining attention as an important tool in sustainable agriculture. This offers a unique opportunity to alleviate the environmental impact of Sargassum muticum (Ochrophyta, Phaeophyceae) as an invasive species by finding new applications for its biomass. In this sense, incorporating green extraction technologies is fundamental to ensure environmental-friendly goals. This research was initiated in an attempt to contribute to an integral valorization system of S. muticum biomass, exploring the biostimulant potential of the solubles obtained from pressed solids, through an autohydrolysis treatment. In addition, we compared the effect of three different liquid phase drying techniques (spray-drying, freeze-drying and convective air-drying). Low stress drying techniques as spray-drying showed better conservation of bioactive compounds and biostimulant potential. A bioassay with Nastrium officinale showed no phytotoxic effects despite high electric conductivity in most of the extracts and concentrations. Dried extracts showed mainly an amorphous structure but occasional crystal formation when spray-dried at low temperatures (Tout = 50 ºC) and after convective air drying (T = 40 ºC). Significant increases in root development were achieved at a concentration of 5 mg L−1 of spray-dried extracts and 50 mg L−1 in case of freeze-dried extracts. Munoo-Liisa vitality index showed best results with 50 mg L−1 of freeze-dried extracts. This study provides important information about the influence of different drying techniques on the physicochemical properties and biostimulant potential of S. muticum aqueous extracts and contributes to the integral valorization of its biomass. [ABSTRACT FROM AUTHOR]

Corn cob is an abundant agricultural residue worldwide, with high potential and interesting composition, and its valorization still needs to be studied. Selectively fractionating its structural components (hemicellulose, cellulose, and lignin), value-added products can be produced, eliminating waste. In this work, integrated fractionation approaches were developed and evaluated. First, an organosolv process was optimized (ethanol:water, 50:50, w/w). Then, as a comparative method, alkaline delignification (using NaOH, 1–2%) was also studied. The organosolv process allowed a significant delignification of the material (79% delignification yield) and, at the same time, a liquid phase containing a relevant concentration (14.6 g/L) of xylooligosaccharides (XOS). The resulting solid fraction, rich in cellulose, showed an enzymatic digestibility of 90%. The alkaline process increased the delignification yield to 94%, producing a solid fraction with a cellulose enzymatic digestibility of 83%. The two later techniques were also used in a combined strategy of hydrothermal processing (autohydrolysis) followed by delignification. The first allowed the selective hydrolysis of hemicellulose to produce XOS-rich hydrolysates (26.8 g/L, 67.3 g/100 g initial xylan). The further delignification processes, alkaline or organosolv, led to global delignification yields of 76% and 93%, respectively. The solid residue, enriched in glucan (above 75% for both combined processes), also presented high enzymatic saccharification yields, 89% and 90%, respectively. The fractionation strategies proposed, and the results obtained are very promising, enabling the integrated upgrading of this material into a biorefinery framework. [ABSTRACT FROM AUTHOR]

The crystalline structure is a biomass recalcitrance factor that hinders chemical or biological access to degrade the plant cell-wall structure. However, controversy persists over whether a ratio of the crystalline region, the crystallinity index, is a critical biomass recalcitrance factor. In this study, an alkaline treatment modified from mercerization was adopted to alleviate the crystalline structure in the xylem of eucalyptus, along with hemicellulose and lignin removal via autohydrolysis and acid–chlorite treatment, respectively. Then, the glucose yield of the treated solid residues was used as a parameter of biomass recalcitrance. The alkaline treatment successfully reduced the crystallinity index, and the maximal reduction ratio was 84.9% when using an 8% sodium hydroxide solution. However, the reduction ratio of the crystallinity index was dependent on the remaining lignin content in the treated solid residues. Additionally, the lignin removal ratio showed critical influence to improve the glucose yield that was even observed in the treated solid residue having a low reduction ratio of the crystallinity index. Consequently, the cellulose crystalline structure is minimally involved with biomass recalcitrance, especially cellulase activity, at least in eucalyptus. [ABSTRACT FROM AUTHOR]

Among the oil palm biomass, oil palm frond leaves (OPFLs) are under-valued since they can be classified as a high recalcitrance feedstock due to the high lignin and hemicellulose content. This work proposes a new way of using OPFLs as alternative cellulose sources for glucose conversion by an application of various pre-treatments at varying parameters. From green pre-treatment, steam explosion (SE) is much more effective in disrupting the OPFLs structure in contrast to hydrothermal (HT) pre-treatment, by a vast dissolution of hemicellulose and depolymerization of lignin. The pre-impregnation with H 2 SO 4 prior to steam explosion was beneficial to enhance the hemicellulose removal up to 89.94 %. The 2D-HSQC NMR analysis divulged the reduction of ß-O-4 linkage and S/G value after the SE and HT pre-treatment, verifying the degradation of lignin-carbohydrate linkage in OPFLs. Meanwhile, the dilute NaOH pre-treatment enhanced the delignification by 87.14 %. SEM analysis revealed a well-disrupted structure of pre-treated OPFLs exposing a higher cellulosic fraction, whereas SEC analysis divulged a decreasing pattern of degree of polymerization of cellulose. The enzymatic analysis revealed that pre-treated OPFLs yielded higher glucose ranging from 29.81 % to 49.98 % w/w, which was ∼3-fold higher than raw OPFLs (14.31 % w/w). A maximum cellulose digestibility (100 %) was achieved by steam-exploded OPFLs after 72 h of enzymatic hydrolysis. This suggests the potency of various pre-treatments to enhance enzymatic saccharification of OPFLs producing a higher glucose yield. [Display omitted] • The oil palm fronds leaves (OPFLs) was pre-treated via various pre-treatments. • The cellulose content of dilute NaOH pre-treated OPFLs was increased up to 49 % w/w. • The steam exploded OPFLs pulp exhibited a well-disrupted cell wall structure. • The amount of ß-O-4 linkages in extracted lignin of pre-treated OPFLs was reduced. • The pre-treated OPFLs yielded 49 % w/w of glucose and 100 % cellulose digestibility. [ABSTRACT FROM AUTHOR]

[Display omitted] • Recent developments in the sustainable production of XOS from agro-industrial waste. • Strategies for XOS characterization and purification prioritizing high prebiotic activity. • Potential industrial applications of XOS with prebiotic characteristics. • Correlation between structural characteristics of XOS and beneficial properties. • Production, structural characteristics and benefits of XOS as prebiotics. Xylooligosaccharides (XOS) are functional oligosaccharides with prebiotic activity, offering exceptional nutritional and health benefits and a wide range of applications. The increasing market demand for healthy products has driven interest in XOS, as they are low-dose prebiotics with high added value, fostering developments in their production. In a sustainable production context, XOS can be obtained from low-cost lignocellulosic raw materials, which require adapted pretreatment techniques to produce high-quality XOS with high process efficiency. One- and two-step methodologies are discussed in terms of increasing XOS production while aiming to limit the co-production of toxic compounds. Autohydrolysis and enzymatic hydrolysis with xylanases stand out as a promising technology for XOS production with high yields. Purification and characterization methodologies are also two important steps to achieve mixtures of XOS with high purity, specific degree of polymerization and substitution to improve their beneficial properties and, consequently, their applications. This review presents the potential of XOS as prebiotics, describing the recent technological production routes, along with advancements in the development of new production processes using alternative substrates, as well as the beneficial effects of their consumption, addressing their latest applications that justify the pursuit of their consolidation in the industrial prebiotic market. [ABSTRACT FROM AUTHOR]

Three different types of biomass sourced from forestry waste (eucalyptus residues), agricultural waste (wheat straw), and energy crop (miscanthus) were used as starting materials to produce hemicellulosic sugars, furans (furfural and hydroxymethylfurfural), and oligosaccharides. A two-step hybrid process was implemented; biomass was first autohydrolysed without any additive to extract hemicelluloses and dissolve it in water. Then, the hydrolysate was treated with a solid acid catalyst, TiO2-WOx, in order to achieve hydrolysis and produce monomeric sugars and furans. This article investigates the role of the biomass type, autohydrolysis experimental conditions, polymerisation degree and composition of hemicelluloses on the performance of the process coupling autohydrolysis and catalytic hydrolysis. The highest global yields of both oligosaccharides and monomeric sugars were obtained from Eucalyptus (37% and 18%, respectively).

Scenedesmus obliquus, a biotechnologically relevant microalgae, was grown in 70 L vertical photobioreactors using non-supplemented secondary brewery wastewater as a culture medium. Upon collection, by mechanical means, the cells were subjected to hydrothermal (autohydrolysis) and dilute acid hydrolysis (0.5 % sulfuric acid) pre-treatments carried out using pressure micro-reactors under isothermal conditions up to 300 min.Both processes enabled a high recovery of soluble sugars (∼50 %) that were, in a great majority, present in the added-value oligomeric form (92 % and 90.5 % for autohydrolysis and dilute acid hydrolysis, respectively). Protein solubilization also presented relevant yields (35 % removal), with dilute acid hydrolysis allowing both higher oligosaccharides and protein productivities at a milder temperature.As compared to the current whole microalgae biomass-based upgrade strategies, the use of these mild processes is extremely promising, as they will enable the future co-production of added-value oligosaccharides, and protein, which can be relevant co-products of a biofuels-based biorefinery.

Miscanthus × giganteus samples were characterized for composition and treated with hot compressed water (hydrothermal or autohydrolysis treatments) at temperatures in the range of 190–240 °C. The liquid phases from treatments were analyzed to assess the breakdown of susceptible polysaccharides into a scope of soluble intermediates and reaction products. The experimental concentration profiles determined for the target compounds (monosaccharides, higher saccharides, acetic acid and sugar-decomposition products) were interpreted using a pseudohomogeneous kinetic mechanism involving 27 reactions, which were governed by kinetic coefficients showing an Arrhenius-type temperature dependence. The corresponding activation energies were calculated and compared with data from the literature. The kinetic equations allowed a quantitative assessment of the experimental results, providing key information for process simulation and evaluation. [ABSTRACT FROM AUTHOR]

Ensuring environmental and social-economic sustainability in the use of materials from lignocellulosic biomass requires their fractionation and valorization of their main components. In this work, we used Eucalyptus urograndis wood to obtain chemicals and energy. The raw material was characterized in chemical terms and then subjected to autohydrolysis under variable operating conditions to optimize the extraction of hemicellulose derivatives relative to cellulose. The kinetics of the pyrolysis process was modeled in terms of activation energy and hydrogen production. Using temperatures in the range of 180–190 °C and treatment times in the range of 15–30 min allowed more than 74.5% of all hemicellulosic components in the raw material to be selectively extracted into the liquid post-hydrolysis phase, more than 90% of all glucan to remain in the solid phase and up to 27.8% of lignin to be removed. The thermal behavior of solid fraction was examined by thermogravimetric analysis, using variable heating rates under a nitrogen atmosphere, and the activation energy can be estimated by using the Flynn-Wall-Ozawa method. Based on the results, the pyrolysis of E. urograndis can be modeled as a first-order reaction. The activation energy (Ea) at a fractional conversion α between 0.3 and 0.7 was 183 to 199 KJ mol−1 for the raw material, whereas that for the solid residue from autohydrolysis ranged from 179 to 186 kJ mol−1 at same fractional conversion when operational temperature in autohydrolysis was upper 185 °C. Based on the results, using temperatures above 180 °C and times of 15 min or longer [i.e., operating at the (0,0) experimental point for the autohydrolysis process] in combination with degrees of conversion from 0.3 to 0.8 reduced the activation energy of the pyrolysis process in relation to the raw material by up to 12% and removed hemicellulose by more 74.5% from it. In parallel, the comparative analysis of the Ea values and the composition of the pyrolysis gas obtained showed a negative relationship between Ea and the amount of hydrogen produced. [ABSTRACT FROM AUTHOR]

Grape pomace (grape skin and seeds) and stems are major by-products of winemaking, of lignocellulosic nature. The aim of this study was to value grape pomace and stems to produce prebiotic oligosaccharides (OS). Grapes from Touriga Nacional and Marselan cultivars (Vitis vinifera L.) were used for conventional red winemaking. The total of extractives, obtained by sequential extraction with dichloromethane, ethanol, and water, was approx. 64.0% (d.w.) for both pomaces, and 46.2% and 59.5% for Marselan and Touriga Nacional stems, respectively. Lignin contents in Marselan stems (26.4%) and pomace (20.4%) were higher than in Touriga Nacional pomace (19.3%) or stems (17.3%). Polysaccharides (hemicelluloses and cellulose) represented 9 and 8.2% of Marselan and Touriga pomaces, and 22.3 and 18.7% of respective stems. After extractives removal, the pomaces and stems were submitted to a hydrothermal treatment (autohydrolysis) to release oligosaccharides from the hemicellulose fraction. Autohydrolysis was carried out following a central composite rotatable design (CCRD) as a function of temperature (142–198 °C) and time (48–132 min). For all materials of both varieties, the production of sugars by autohydrolysis could be described by second-order models. Highest sugar productions were: 81.2 g/kg (d.w.) extracted Marselan pomace; 76.3 g/kg (d.w.) extracted Touriga Nacional pomace; 116.3 g/kg (d.w.) extracted Marselan stems; and 168.4 g/kg (d.w.) extracted Touriga Nacional stems. Yields of 99% OS were obtained by autohydrolysis at 170 °C/90 min. [ABSTRACT FROM AUTHOR]

The production of xylooligosaccharides (XOS) from Jiuzao was studied using a two-stage process based on autohydrolysis pretreatment followed by enzymatic hydrolysis. Jiuzao was autohydrolyzed under conditions where temperature, time, particle size, and solid-liquid ratio were varied experimentally. Optimal XOS production was obtained from Jiuzao with a >20 mesh particle size treated at 181.5 °C for 20 min with a 1:13.6 solid-liquid ratio. Subsequently, optimal enzymatic hydrolysis conditions for xylanase XynAR were identified as 60 °C, pH 5, and xylanase XynAR loading of 15 U/mL. Using these conditions, a yield of 34.2% XOS was obtained from Jiuzao within 2 h. The process developed in the present study could enable effective and ecofriendly industrial production of XOS from Jiuzao. [ABSTRACT FROM AUTHOR]

Hemicelluloses are amorphous polymers of sugar molecules that make up a major fraction of lignocellulosic biomasses. They have applications in the bioenergy, textile, mining, cosmetic, and pharmaceutical industries. Industrial use of hemicellulose often requires that the polymer be hydrolyzed into constituent oligomers and monomers. Traditional models of hemicellulose degradation are kinetic, and usually only appropriate for limited operating regimes and specific species. The study of hemicellulose hydrolysis has yielded substantial data in the literature, enabling a diverse data set to be collected for general and widely applicable machine learning models. In this paper, a dataset containing 1955 experimental data points on batch hemicellulose hydrolysis of hardwood was collected from 71 published papers dated from 1985 to 2019. Three machine learning models (ridge regression, support vector regression and artificial neural networks) are assessed on their ability to predict xylose yield and compared to a kinetic model. Although the performance of ridge regression was unsatisfactory, both support vector regression and artificial neural networks outperformed the simple kinetic model. The artificial neural network outperformed support vector regression, reducing the mean absolute error in predicting soluble xylose yield of test data to 6.18%. The results suggest that machine learning models trained on historical data may be used to supplement experimental data, reducing the number of experiments needed.

This study proposes an efficient strategy for co-producing high-value-added xylooligosaccharides (XOS) and humic-like acid (HLA) from vinegar residue based on two-step hydrothermal pretreatments. During the first-step hydrothermal pretreatment (170 °C, 50 min), 29.1% of XOS (X2-X6) was obtained. The XOS yield was further improved to 36.2% with endoxylanase hydrolysis, thereby increasing the value of (X2-X4)/XOS from 0.8 to 1.0. Subsequently, the second-step hydrothermal pretreatment was investigated to produce HLA from the solid residue of the first-step hydrothermal pretreatment. The highest HLA yield was 15.3% in the presence of 0.6 mol/L of KOH at 210 °C for 13 h. In addition, 31.7% of hydrochar by-product was obtained. The mass balance results showed that 1000 g of vinegar residue produced 67.9 g of XOS, 91.6 g of HLA, and 189.5 g of hydrochar. Therefore, this study provides a promising pathway for comprehensive use of lignocellulosic biomass in producing XOS and HLA.

We propose a closed-loop pretreatment process, wherein volatiles produced during steam explosion pretreatment were recovered and reintroduced as acid catalysts into the pretreatment system. The volatiles were separated through a drastic decompression process followed by a steam explosion process and recovered as a liquified catalyst (LFC) through a heat exchanger. The LFC effectively served as an acid catalyst for hemicellulose hydrolysis, significantly decreasing residence time from 90 min to 30 min to achieve 80 % conversion yield at 170 °C. Hydrolysates with high content of lower molecular weight oligomeric sugars were obtained using LFC, and were considered advantageous for application as prebiotics. These results are attributed to the complementary features of acetic acid and furfural contained within the LFC. Computational simulation using Aspen Plus was used to investigate the effects of recycling on LFC, and it demonstrated the feasibility of the catalyst-recirculating system. A validation study was conducted based on simulation results to predict the actual performance of the proposed pretreatment system. Based on these results, the recirculating system was predicted to improve the conversion yield and low-molecular weight oligomers yield by 1.5-fold and 1.6-fold, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

The valorisation of agro-industrial residues presents a challenge in obtaining economically sustainable and environmentally friendly industrial processes. Olive pomace is a by-product generated in large quantities, from olive oil extraction. This residue mostly consists of lignocellulosic materials. The aim of this study was to evaluate the potential use of extracted olive pomaces (EOP) obtained from olives with different ripening indexes (RI) and from different cultivars (Cobrançosa; RI = 2.5; 3.3 and 4.7; and Galega Vulgar; RI = 1.8; 2.9 and 4.8), to produce bioactive oligosaccharides from hemicelluloses by autohydrolysis. The hydrothermal treatment conditions were optimized by Response Surface Methodology, following a central composite rotatable design (CCRD), as a function of temperature (T: 142–198 °C) and time (t: 48–132 min), corresponding to severity factor (SF) values from 3.2 to 4.9. For all pomace samples, soluble sugar production was described by concave surfaces as a function of temperature and time. Autohydrolysis with SF equal or higher than 4.0 produced higher sugar yields, with maximum values around 180 g glucose equivalent/kg EOP for SF of 4.7 (190 °C/120 min) or 4.9 (198 °C/90 min). These values were similar for both cultivars and were not dependent on the ripening stage of the olives. Maximum oligosaccharide (OS) yields of 98% were obtained by autohydrolysis with SF of 4.0. The increase in SF to 4.9 resulted in a decrease in OS yield to 86–92%, due to the release of monomeric sugars. The monosaccharides were mostly xylose (55.8–67.7% in Galega; 50.4–69.0% in Cobrançosa liquid phases), and glucose, galactose, arabinose and rhamnose, in smaller quantities. Therefore, the production of bioactive xylo-oligosaccharides (XOS) from olive pomaces mainly depends on the hydrothermal conditions used. [ABSTRACT FROM AUTHOR]

In this study, the combined strategy of using high solid load, on-site enzyme cocktails and surfactant was evaluated in saccharifications of hydrothermally pretreated sugarcane bagasse (HP-SB) and ethanol production. The hydrolyses were carried in fed-batch mode with a solid load of 10–40% (w/v) at time intervals of 12 h, using two homemade enzyme extracts (ES1 from Aspergillus niger monoculture and ES2 from A. niger, Trametes versicolor and Pleurotus ostreatus consortium), 10 FPU/gds of cellulase loading at 50 °C for 72 h. After optimization of solid loading, new saccharifications were performed with the addition of 5% (w/v) surfactant (Triton X-100). The HP of SB led to a significant reduction of 69.26% in hemicelluloses content, but also preserved the cellulose fraction in HP-SB. The increase of HP-SB load in hydrolysis from 10 to 35% significantly improved the release of total reducing sugars (TRS), with an increase of 188.54% in ES1 and 177.46% in ES2. The use of Triton X-100 in saccharifications of HP-SB (30% w/v) also positively contributed to TRS production, with an increase in TRS of 6.22% in ES1S and 24% in ES2S. The fermentation of the hydrolysate after surfactant-assisted hydrolysis of HP-SB (30% w/v) led to an ethanol yield of 81.70% for F1S and 88.03% for F2S. Results demonstrated that the integrated use of high solid load, low-cost on-site enzyme cocktail and surfactant (Triton X-100) can be a promising approach to improve the efficiency of bioconversion of lignocellulosic biomass to fermentable sugars. [ABSTRACT FROM AUTHOR]

This work examines the recovery of phenolic compounds through the autohydrolysis of eucalyptus wood residues. The hydrolysis of pin chips was carried out using hot water under different conditions. This treatment was capable of extracting xylosaccharides, phenols, furfural (FUR), hydroxymethylfurfural (HMF) and acetic acid (AAc). The highest phenolic contents were attained at 160 °C and 110 minutes, where total phenolic compounds (TPC) reached 1.33% gallic acid equivalent (GAE) and syringaldehyde (SA) and vanillin (VAN) were at 0.01% each, in pin chips dry basis (d.b.). The capacity to extract phenolic compounds from pin chip hydrolysate through aqueous two-phase systems (ATPS) based on PEG 2000 and sodium citrate was demonstrated. High extraction efficiency was obtained (99.8% for the TPC, 82.3% for the SA, 94.9% for the VAN, 89.3% for the FUR and 70.9% for the AAc). The recovery of sugars in the bottom phase was 58.4%.

The result showed total phenolic content, total flavonoid content and radical scavenging activity in ethanol extracts higher than oil extracts and massage products of Boesenbergia rotunda, Alpinia conchigera, Alpinia galangal, and Alpinia siamensis. Fourier-transform infrared spectroscopy of the ethanol extracts provided specific peaks in a range of 4,000 to 550 cm1 . Chemical differentiation between Alpinia sp. and Boesenbergia sp. was indicated by main peaks that corresponded to aromatic and N-H in amino acids, O-H in phenyl group, and C-O in carbohydrates and glycoprotein. Chemical differentiation among three Alpinia species were wavenumber ranges of C-O in acid or ester, C-O in carbohydrates and glycoprotein, and C-H in isoprenoids. The cluster and PCA analysis showed good separation of chemical compositions and antioxidant activity among the ethanol extract, massage solution and oil extract. Additionally, Ni, and Cd were found in all massage products, especially Ni above its maximum permission level.

Over the course of the COVID‐19 pandemic, mRNA‐based vaccines have gained tremendous importance. The development and analysis of modified RNA molecules benefit from advanced mass spectrometry and require sufficient understanding of fragmentation processes. Analogous to the degradation of RNA in solution by autohydrolysis, backbone cleavage of RNA strands was equally observed in the gas phase; however, the fragmentation mechanism remained elusive. In this work, autohydrolysis‐like intermediates were generated from isolated RNA dinucleotides in the gas phase and investigated using cryogenic infrared spectroscopy in helium nanodroplets. Data from both experiment and density functional theory provide evidence for the formation of a five‐membered cyclic phosphate intermediate and rule out linear or six‐membered structures. Furthermore, the experiments show that another prominent condensed‐phase reaction of RNA nucleotides can be induced in the gas phase: the tautomerization of cytosine. Both observed reactions are therefore highly universal and intrinsic properties of the investigated molecules. [ABSTRACT FROM AUTHOR]

Summary: This study deals with the antioxidant and functional potential of subcritical water extracts from edible mushrooms, in comparison to commercial products. Pleurotus citrinopileatus extracts showed the highest phenolic content and antioxidant properties. Similar results were determined in commercial extracts of Coriolus versicolor. The highest growth inhibition in selected human carcinogenic cells was identified for the P. citrinopileatus extract obtained during heating up to 160 °C. Rheological studies confirmed that glucan‐based hydrogels prepared with mushroom extracts exhibited enhanced viscoelastic properties compared to those formulated with commercial products. The extracts providing the strongest gels were obtained from Pleurotus eryngii, followed by Hericium erinaceus and Pleurotus citrinopileatus. No water syneresis for the proposed hydrogels was observed. The formulated hydrogels could be interesting for their application in the food sector. [ABSTRACT FROM AUTHOR]

Purpose: In this study, to obtain xylose-based fermentation media from autohydrolysis liquors of sunflower stalk by using commercial xylanase formulation was aimed. Xylose is generally produced from xylan by diluted acid hydrolysis that causes the formation of some unwanted compounds during the process. As an alternative to dilute acid hydrolysis method, enzymatic hydrolysis of xylan can provide more specific hydrolysis under moderate conditions and does not cause the formation of undesirable compounds. Methods: Xylose production was carried out with Trichoderma longibrachiatum xylanase on solubilized xylan form of sunflower stalk, which was hydrothermally pretreated for 1 h at 160 °C. The effects of substrate concentration and enzyme activity were investigated for the production of xylose. To obtain a high xylose yield and selectivity, the optimization study was conducted by the response surface methodology. Results: The optimum substrate concentration and enzyme activity were found as 60 mg ds/mL CAL and 234 U/mL, respectively. Under the optimum condition, xylose yield and selectivity were found to be 69.5% and 8.2 g/g, respectively. Conlusion: This study showed that xylose could be produce with a high yield without requiring a neutralization process and corrosive chemical reagent apart from water. [ABSTRACT FROM AUTHOR]

Three different types of biomass sourced from forestry waste (eucalyptus residues), agricultural waste (wheat straw), and energy crop (miscanthus) were used as starting materials to produce hemicellulosic sugars, furans (furfural and hydroxymethylfurfural), and oligosaccharides. A two-step hybrid process was implemented; biomass was first autohydrolysed without any additive to extract hemicelluloses and dissolve it in water. Then, the hydrolysate was treated with a solid acid catalyst, TiO2-WOx, in order to achieve hydrolysis and produce monomeric sugars and furans. This article investigates the role of the biomass type, autohydrolysis experimental conditions, polymerisation degree and composition of hemicelluloses on the performance of the process coupling autohydrolysis and catalytic hydrolysis. The highest global yields of both oligosaccharides and monomeric sugars were obtained from Eucalyptus (37% and 18%, respectively). [ABSTRACT FROM AUTHOR]

Abstract Background Soil-derived exogenous ash (EA) poses a challenge toward lignocellulosic autohydrolysis due to its buffering capacity. Previous works focusing on this phenomenon have failed to also investigate the role that soluble salts, and organic matter plays in this system. Herein, sodium phosphate and sodium humate were employed as model buffering compounds representing soluble salts and organic matter and dosed into a de-ashed wheat straw (DWS) autohydrolysis process to show the potential impacts of WS attached soil conditioners on the WS autohydrolysis efficiency which would further affect the enzymatic digestibility of autohydrolyzed WS. Results Results showed that with the increasing loadings of sodium phosphate and sodium humate resulted in elevated pH values (from 4.0 to 5.1 and from 4.1 to 4.7, respectively). Meanwhile, the reductions of xylan removal yields from ~ 84.3–61.4% to 72.3–53.0% by loading (1–30 g/L) sodium phosphate and sodium humate during WS autohydrolysis lead to a significant decrease of cellulose accessibilities which finally lead to a reduction of the enzymatic digestibility of autohydrolyzed WS from ~ 75.4–77.2% to 47.3–57.7%. Conclusion The existence of different types soil conditioner model compounds results in various component fractions from autohydrolyzed WS in the process of autohydrolysis. A lack of sufficient xylan removal was found to drive the significant decrease in enzymatic accessibility. The results demonstrated the various effects of two typical tested soil conditioners on WS autohydrolysis and enzymatic hydrolysis.

This work deals with the study of tea stalks from pruning debris using environmental friendly extraction technology to offer new healthy properties. In the manufacturing tea industry, tea trees require to be pruned every year and most of their remains are discarded as a waste with no economic value. Microwave aqueous extraction and pressurized hot water extraction process (autohydrolysis) were used to recover bioactive compounds from the tea branches. Operating at a fixed solid: liquid ratio (1:15), the effect of the maximum heating temperatures from 140 to 220 °C was studied. Liquid extracts were analysed for total phenolic, oligosaccharides, protein, mineral and heavy metals content, as well as for antioxidant capacity. The antitumoral possibilities were also determined for selected samples. The obtained results indicated that both processes could be used as an alternative to recover bioactive compounds from tea wastes, although microwave-assisted extraction allowed saving time when compared with autohydrolysis processing. The temperature exhibited a relevant effect on the total phenolic content and antioxidant capacity, decreasing with the microwave treatment and increasing with the autohydrolysis temperature. The obtained extracts could be adequate for incorporation in food and non-food fields.

Corn cob is an abundant agricultural residue worldwide, with high potential and interesting composition, and its valorization still needs to be studied. Selectively fractionating its structural components (hemicellulose, cellulose, and lignin), value-added products can be produced, eliminating waste. In this work, integrated fractionation approaches were developed and evaluated. First, an organosolv process was optimized (ethanol:water, 50:50, w/w). Then, as a comparative method, alkaline delignification (using NaOH, 1–2%) was also studied. The organosolv process allowed a significant delignification of the material (79% delignification yield) and, at the same time, a liquid phase containing a relevant concentration (14.6 g/L) of xylooligosaccharides (XOS). The resulting solid fraction, rich in cellulose, showed an enzymatic digestibility of 90%. The alkaline process increased the delignification yield to 94%, producing a solid fraction with a cellulose enzymatic digestibility of 83%. The two later techniques were also used in a combined strategy of hydrothermal processing (autohydrolysis) followed by delignification. The first allowed the selective hydrolysis of hemicellulose to produce XOS-rich hydrolysates (26.8 g/L, 67.3 g/100 g initial xylan). The further delignification processes, alkaline or organosolv, led to global delignification yields of 76% and 93%, respectively. The solid residue, enriched in glucan (above 75% for both combined processes), also presented high enzymatic saccharification yields, 89% and 90%, respectively. The fractionation strategies proposed, and the results obtained are very promising, enabling the integrated upgrading of this material into a biorefinery framework.

Seaweed contains a variety of bioactive compounds; the most abundant of them are polysaccharides, which have significant biological and chemical importance. Although algal polysaccharides, especially the sulfated polysaccharides, have great potential in the pharmaceutical, medical and cosmeceutical sectors, the large molecular size often limits their industrial applications. The current study aims to determine the bioactivities of degraded red algal polysaccharides by several in vitro experiments. The molecular weight was determined by size-exclusion chromatography (SEC), and the structure was confirmed by FTIR and NMR. In comparison to the original furcellaran, the furcellaran with lower molecular weight had higher OH scavenging activities. The reduction in molecular weight of the sulfated polysaccharides resulted in a significant decrease in anticoagulant activities. Tyrosinase inhibition improved 2.5 times for hydrolyzed furcellaran. The alamarBlue assay was used to determine the effects of different Mw of furcellaran, κ-carrageenan and ι-carrageenan on the cell viability of RAW264.7, HDF and HaCaT cell lines. It was found that hydrolyzed κ-carrageenan and ι-carrageenan enhanced cell proliferation and improved wound healing, whereas hydrolyzed furcellaran did not affect cell proliferation in any of the cell lines. Nitric oxide (NO) production decreased sequentially as the Mw of the polysaccharides decreased, which indicates that hydrolyzed κ-Carrageenan, ι-carrageenan and furcellaran have the potential to treat inflammatory disease. These findings suggested that the bioactivities of polysaccharides were highly dependent on their Mw, and the hydrolyzed carrageenans could be used in new drug development as well as cosmeceutical applications.

Background: Autohydrolysis is an extensively investigated pretreatment method due to its environmental friendliness. During autohydrolysis, most xylan from hemicellulose can be converted into xylooligosaccharides (XOS), and cellulose in the autohydrolyzed residues can be transformed into glucose after enzymatic hydrolysis. Both of these are value-added biochemicals in the biorefining process. In this work, paper mulberry (PM), which contains abundant protein, was utilized as a raw material to coproduce XOS and single-cell protein (SCP) through autohydrolysis and fermentation technologies. Results: The results showed that 8.3 g of XOS and 1.8 g of amino acids could be recovered in the autohydrolysate (based on 100 g raw material) after autohydrolysis (170 °C, 1 h). Moreover, 5.7 g of low-DP XOS along with 1.8 g of amino acids could be further obtained from the autohydrolysate after hydrolysis with endo-β-1-4-xylanase. In addition, 20.1 g of fermentable monosaccharides was recovered after hydrolyzing the autohydrolyzed PM with cellulase, which can be used to produce 4.8 g of SCP after fermentation with Candida utilis. Conclusion: As a valuable application of PM, a novel process is proposed to coproduce amino acid-rich XOS and SCP through autohydrolysis. The carbohydrate of PM is effectively converted to high value-added products. [ABSTRACT FROM AUTHOR]

Eucalyptus regnans wood samples were treated with water under diverse conditions, in order to obtain soluble hemicellulose-derived products. The composition of the liquid phase from the treatment leading to the best results was characterized in depth using a combination of spectrophotometric, spectrometric and chromatographic methods; and the susceptibility of the treated solids to further fractionation by organosolv delignification was assessed in additional experiments. The chemical and physicochemical properties of the resulting lignin were determined, and the suitability of the delignified solids as substrates for the one-pot manufacture of ethyl levulinate was evaluated on a quantitative basis. [ABSTRACT FROM AUTHOR]