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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]

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]

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]

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]

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 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]

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]

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]

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]

Although hardwood (Eucalyptus) kraft lignin is rich in low molecular weight (low-Mw) lignin derivates, finding green solvents or processes for fractionating low-Mw constituents with high selectivity from kraft black liquor remains challenging. This study employed ethanol/water (EW) solutions of varied proportions in combination with lignin autohydrolysis to fractionate lignin from Eucalyptus kraft liquor into EW-soluble and EW-insoluble lignin fractions of low (496 ∼ 644 g·mol−1) and high (1563 ∼ 1862 g·mol−1) molecular weight, respectively. EW-soluble and EW-insoluble fractions were comprehensively characterized by GC-MS and 2D HSQC NMR. The fractionation yield of low-Mw lignin is 41.1 % (based on total recovered lignin content) with hydrolysis temperature of 120 °C, 3 h reaction time, and a 1:1 ethanol-to-water volume ratio. S-type lignin-derived monomeric derivates are predominant in the EW-soluble fraction. In particular, 2,6-dimethoxyphenol, syringaldehyde, and acetosyringone are relatively high in the EW-solution fraction, being 30.04, 11.74, and 38.75 mg/g, respectively. In contrast, the EW-insoluble lignin fraction is dominated by stilbene structures and β−β linkages, exhibiting a more uniform dispersity than unfractionated lignin. This study has developed a direct fractionation method with high selectivity of the low-Mw components, which has great application potential for producing platform chemical compounds, fuels, and pharmaceutical precursors. [Display omitted] • A green approach for the direct and highly selective fractionation of low-Mw lignin is developed. • EW-soluble fractions show a high selectivity for lignin-derived S-type monomers. • Lignin oxidation can occur during autohydrolysis in EW-solution. [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]

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]

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]

The integration of processes offers promising avenues for valorization of the tobacco waste, enabling the production of commercially significant compounds beyond traditional tobacco leaves designation. This research delves into the feasibility of extracting xylo-oligosaccharides (XOS) from tobacco stems via hydrothermal pretreatment. Emphasis was laid on XOS release kinetics from high solid loads (20% w/v) during pretreatment. The optimal conditions, which facilitated maximum oligomer recovery with minimal degradation compounds and reducing sugar solubilization, were then scaled up. The resultant solid fraction underwent enzymatic hydrolysis at varied solid loads (5%, 10%, and 15% w/v). Subsequent to this, succinic acid production was targeted, propelling the optimal enzymatic hydrolysate towards fermentation using the bacterium Actinobacillus succinogenes. Key findings revealed that a temperature of 190 °C during 8-min emerged as the most effective pretreatment conditions, yielding XOS at 49.54% with a concentration of 11.11 g.L−1. Enzymatic hydrolysis remained relatively uninfluenced by variations in solid loads, thereby permitting the use of high solid loads (15% w/v) to obtain concentrated hydrolysates at 49.37 g.L−1 with a conversion yield of 62.90%. Markedly, this study pioneered the demonstration of tobacco waste as a viable precursor for biosuccinic acid synthesis. Succinic acid concentration stood at 16.88 g.L−1, achieving a yield of 42%. A comprehensive mass balance evaluation spotlighted the potential to derive 56 kg of XOS and 78 kg of succinic acid per 1000 kg of tobacco raw biomass by the process developed herein. [Display omitted] • Hydrothermal pretreatment was effective in the fractionation of lignocellulose. • High solid concentration and retention time below 10 min enable XOS yield of 50%. • Enzymatic hydrolysis yielded 60% glucose with high solids load and low enzyme load. • Succinic acid yield of 0.42 g/g and productivity of 1.54 g/L/h were achieved. [ABSTRACT FROM AUTHOR]

It was proposed that pre-hydrolysing tule (Typha domingensis Pers) would make it possible to produce handsheets with strength-related properties similar to those of conventional commercial paper, in addition to valorizable hemicelluloses. The hypothesis was tested with a biorefining scheme involving autohydrolysis. Conditions were optimized to maximize the extraction of hemicelluloses while preserving glucan integrity. The autohydrolysis at a liquid to solid ratio of 13 at 141 °C for 45 min (optimized conditions) provided a commercially useful liquor containing primarily tule hemicelluloses. The autohydrolysis of tule before alkaline extraction made it possible to obtain a valuable liquid phase comprising between 23.3% and 71.6% of all hemicelluloses in the raw material. The gross heating value for the hydrolyzed tule was increased (1.6% to 7.9 %) with respect the raw material. The solid phase was subjected to soda-anthraquinone pulping. The yield, ethanol extractives, kappa number, viscosity, glucan, xylan, Klason lignin, soluble lignins, as well as the tensile index were evaluated. Tule was found to be amenable to industrial processing for the production of quality cellulose derivatives. Autohydrolysis provided valorizable liquor in addition to solid that yielded soda-anthraquinone pulp having properties similar to those obtained in its absence, but using milder operating conditions. [ABSTRACT FROM AUTHOR]

In this work, the powder of the coconut husk was submitted to the hydrothermal pretreatment steam explosion. The effect of this pretreatment under the rigid lignocellulosic structure of biomass was evaluated from the analysis of hydrolyzable composition, XRD, specific surface area, and pore volume. The results confirmed that there was thermal degradation of hemicellulose, with an increase of the biomass crystallinity and porosity, favoring the adsorption of the monocomponent Cu2+ and Cd2+ at room temperature. The kinetic pseudo-second-order model and the Langmuir model isotherm described the adsorption process, with a maximum adsorption capacity of Cu2+ and Cd2+ of 18.86 and 17.9 mg/g, respectively. The effect of temperature on monocomponent adsorption was also studied. Coconut husk powder can be used efficiently after steam explosion for metal ion adsorption. [ABSTRACT FROM AUTHOR]

• Revalorization of vine shoots by a low time consuming and sustainable treatment. • Synergic effect of the temperature and reaction time during the autohydrolysis. • Simulation of microwave-assisted autohydrolysis conditions by conventional heating. • Similar characteristic of the products independently of the heating method. This work deals with the revalorization of an important winery residue such as the vine shoots by the obtaining of oligosaccharides with potential prebiotic activity. The manufacture of these added-value products was performed by an autohydrolysis treatment assisted with microwaves to make the process less time consuming and more environmentally friendly. The influence of the reaction time (0–40 min) and the temperature (140–200) on the production of oligosaccharides during the microwave-assisted autohydrolysis was evaluated. The highest concentration of oligosaccharides (168.3 g/Kg oven-dried vines shoots) was achieved during the treatment carried out at 180 °C for 20 min. To assess the benefits of the assistance of the autohydrolysis treatment with the microwaves a conventionally heated treatment was performed using conditions (180 °C for 15 min) that provoked similar effects on the solubilisation of the hemicellulosic fraction. This treatment permitted the obtaining of 203.5 g oligosaccharides/Kg oven-dried vines shoots using 61.0% more of the time needed to carry out the microwaves-assisted autohydrolysis. Although the microwave-assisted treatment permitted the manufacture of a lower amount of oligosaccharides, only consumed 28.8% of the energy needed to perform the conventionally heated treatment. The oligosaccharides manufactured by the two treatments were substituted xyloglucans with different polymerization and acetylation degrees, which due to their potential prebiotic activity could be highly appreciated by pharmaceuticals and food industries. Thus, this work demonstrated the environmental sustainability of the microwave-assisted autohydrolysis for the revalorisation of the vine shoots. [ABSTRACT FROM AUTHOR]

• Autohydrolysis of post-fibre extraction pulp from banana pseudostem was studied. • A high concentration of malto-oligosaccharides was obtained in the liquors. • Solid fraction presented an improved enzymatic digestibility for further valorization. • Two-stage autohydrolysis improved oligosaccharides production and solid digestibility. Banana's pseudostem pulp (BPP) is a potential by-product obtained in the mechanical fiber extraction of banana's pseudostem. Its chemical characterization revealed to have an interesting composition, with a high polysaccharides content and low content in lignin, which makes it particularly relevant for the biorefinery's biochemical platform. Autohydrolysis pretreatment, studied under isothermal (140 °C) and non-isothermal conditions (140–220 °C), yielded oligosaccharides, mainly gluco -oligosaccharides, as the main soluble products. The highest oligosaccharides production (24 g/100 g raw material) was obtained at a severity factor of 2.3. Autohydrolysis pretreatment effectively disrupted the structure of the material, inducing an improvement of the enzymatic digestibility from 73% for the raw material up to 90% for the most severe conditions. Two stage autohydrolysis, with increasing severity, was also studied, allowing to obtain a higher amount of oligosaccharides (32 g/100 g raw material) and higher digestibility of the remaining solid (up to 97%). [ABSTRACT FROM AUTHOR]

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 cm-1. 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. [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%. [ABSTRACT FROM AUTHOR]

Integrated fractionation process based on autohydrolysis (H) and subsequent formic acid delignification (FAD) has been considered as an effective strategy to separate the main lignocellulosic components in view of the biorefinery. For the better understanding of the structural changes of the lignin during the integrated process, the fractionated aspen lignins were thoroughly characterized by Fourier transform infrared (FT IR), 13C, two-dimensional heteronuclear single quantum coherence (2D-HSQC) and 31P nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), and thermogravimetric analysis (TGA). Compared to the milled wood lignin (MWL), the fractionated lignins had higher amounts of phenolic OH groups as due to the cleavage of β-O-4 linkages and less alcoholic OH groups mainly due to the esterification of the aliphatic OH groups by formic acid. Demethylation action of the lignin was not significant during the FAD process. More syringyl-propane (S) units were extracted during the H-FAD process than guaiacyl-propane (G) units resulting in a higher S/G ratio and more OCH 3 in the fractionated lignins. Furthermore, autohydrolysis of aspen at higher temperature led to more condensation of the fractionated lignins which exhibited higher molecular weight and more β-5 and β-β linkages. The fractionated lignins exhibited high purities due to the breakage of the lignin-carbohydrate bonds. • Lignin with high phenolic OH and OCH 3 and high purity was obtained. • Aliphatic OH group was highly esterified by formic acid. • β-O-4 cleavage accompanied by formation of condensed aromatic structure • Autohydrolysis led to higher molecular weight and less formate ester in lignin [ABSTRACT FROM AUTHOR]

A combination of biorefinery processes (hydrothermal and membrane processing) was per- formed for the manufacture of oligosaccharides and natural phenolic compounds from poplar hemicelluloses. Both, oligosaccharides and phenolics have multiple potential appli- cations related to their bioactive properties. Firstly, non-isothermal autohydrolysis of poplar was performed to obtain oligosaccharides from the hemicellulosic fraction, while cellulose and lignin remained almost unaltered in the spent solid allowing their valorization in fur- ther processing stages. Operating at 210°C and liquid to solid ratio of 6 kg/kg, solutions containing 28.71 g oligosaccharides/L were obtained. Secondly, membrane refining of the resulting solution and further freeze-drying resulted in a product with high purity (90 kg of substituted oligosaccharides/100 kg of non-volatile compounds). The yield of substituted oligosaccharides in the target product accounted 16.6 kg/100 kg of poplar wood. Product characterization was accomplished by HPLC, HPSEC, HPAEC-PAD and MALDI TOF-MS. The data confirmed the presence ofbackbones containing up to DP13 pentose units, with a complex substitution pattern by acetyl groups and 0-methyl-uronic moieties. Additionally, the presence of natural phenolic compounds bounded to oligosaccharides conferred antioxidant properties to the target product. Substituted oligosaccharides and phenolics are postulated as valuable products with interest in food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study deals with the valorisation of tea leaves from the agricultural pruning remains using clean technologies with low environmental impact. Leaves with null commercial interest were dismissed during the pruning season, however with a sequential combination of microwave hydrodiffusion and gravity (MHG), ultrasound-assisted (US) and pressurized hot water (AH) extractions was possible to recover bioactive compounds. An initial pre-treatment was performed using MHG at selected irradiation powers to facilitate the liberation of antioxidants through the cell membrane. The solid phases were processed by three ways: i) ultrasound bath system (80 °C, 80 KHz, from 15 to 60 min); ii) AH technology (non-isothermal treatment with maximum temperature from 140 to 200 °C); and iii) a sequence of the three aforementioned technologies. Both raw material and liquors were analysed to determine fundamental physicochemical, phytochemical or biological properties. Leaves debris showed positive results in bioactive compounds with a maximum value of total phenolic around 130 mg GAE/g extract in the sequential combination. Antioxidant capacity ranged from 0.3 to 0.9 g Trolox/g extract. The combination of green extraction technologies guarantees an efficient recovery of bioactive compounds, creating the possibility of new products that improve the wellbeing. [ABSTRACT FROM AUTHOR]

Pressurized hot water pretreatment was performed on softwood (SW) and hardwood (HW) chips following the same conditions (1 h at 170 °C) in order to partly hydrolyse hemicelluloses. The complete characterization of these sugar enriched autohydrolysates (AH) being rather complex, two different purification methods were conducted. Nanofiltration (NF) 1kDa membrane and ultrafiltration (UF) 3 and 5kDa membranes were used to separate oligosaccharides (OS) from undesired compounds and for their molar mass fractionation. Granulated activated charcoal (GAC) adsorption was also used for hydrolysates detoxification. The chemical nature of OS and side charge groups vary significantly depending of the fractions obtained, e. g. xylans' chain length is positively correlated with the degree of acetylation. UF at 5kDa allows for the total separation of galactoglucomannans (GGMs) from xylans, in SW AH, however, this result was not achieved with HW. From the acid soluble lignin (ASL) removal point of view, membrane filtration from 1kDa is more efficient than activated carbon treatment concerning HW AH, on the contrary to SW AH. Regarding the lignin to OS ratio, for both species, GAC leads to a better sugar purity. [ABSTRACT FROM AUTHOR]

Spent coffee grounds (SCG) are a promising raw material for galactomannan (GalM) production based upon its enrichment in galactomannan polysaccharides. In this work, SCG was pretreated by autohydrolysis for maximumly improving GalM extractability by endo -mannanase. The GalM in the prehydolyzate (GalM-PH) and enzymatic hydrolyzate (GalM-EH) were obtained by ethanol precipitation and characterized. Under the optimized autohydrolysis conditions, 50.1% of GalM in pretreated SCG was converted into free GalM in enzymatic hydrolyzate. Compositional analysis results revealed that GalM-PH was comprised of 81.7% galactomannan, higher than that of GalM-EH (76.4%). The molecular weight of GalM-PH and GalM-EH were 44.5 kDa and 28.0 kDa, respectively. Antioxidant assays indicated that both GalM-EH and GalM-PH could scavenge 2,2-diphenyl-1-picryl-hydrazyl radicals and hydroxyl radicals. Immunological and prebiotics analysis showed all GalM preparations exhibited pronounced activities for proliferating the probiotics and proliferating the Macrophages cell for NO production, in which the GalM-EH outperformed the GalM-PH. These results imply that the GalM extracted from SCG are the bioactive substances that can be used as antioxidant, prebiotics, and immunostimulants. Unlabelled Image • Autohydrolysis improved the enzymatic hydrolysis of spent coffee ground. • GalM with low molecular weight can be obtained by endo -mannanase. • GalM showed biologically active of prebiotic and antioxidant. [ABSTRACT FROM AUTHOR]

Eucalyptus sawdust is a residue from the pulp industry, currently used for energy production. Organosolv and autohydrolysis pretreatments for integrated valorization of this residue within a biorefinery approach was investigated. Organosolv pretreatment was used for selectively extract lignin, and autohydrolysis pretreatment was effective for hemicellulose solubilization. Glucose production of 33.7 g/100 g eucalyptus was achieved after organosolv pretreatment, while dissolving 6.4 g/100 g eucalyptus of xylan-derived sugars and recovering 10.3 g/100 g eucalyptus of lignin after precipitation. After autohydrolysis pretreatment, glucose production of 32.3 g/100 g eucalyptus was reached, while 7.5 g/100 g eucalyptus of xylan-derived sugars and 2.7 g/100 g eucalyptus of acetyl groups were effectively dissolved in a separate liquid stream. Non-ionic surfactant (PEG 6000) was used to enhance cellulose hydrolysis. Integration of a suitable pretreatment and enzymatic hydrolysis steps was shown to be a feasible strategy for the co-production of different value-added products (lignin, xylose, xylo-oligomers, acetic acid), towards a cost-effective eucalyptus biorefinery. • Pretreatments were conducted under mild conditions for total utilization of biomass. • Organosolv pretreatment recovered almost 40% of lignin in eucalyptus sawdust. • Enzymatic hydrolysis of pretreated substrates yielded up to 82% of glucan to glucose. • PEG 6000 weakened the negative effect of lignin on cellulose enzymatic hydrolysis. • The proposed biorefinery scheme achieved an integral use of eucalyptus sawdust. [ABSTRACT FROM AUTHOR]

Dehydrated Laminaria ochroleuca was processed by autohydrolysis with compressed hot water to extract bioactive compounds. Both the whole algae and individual fractions obtained (solid residue and liquor) were characterised to assess its functional properties for future innovative food applications. Purée-like systems were developed by combining ultrasonic and thermal technologies to maximise the antioxidant capacity and were evaluated by determining colour, texture, rheology, syneresis and the presence of bioactive compounds. Overall, the obtained results indicated that L. ochroleuca is a valuable resource that can be used as a whole or taking advantage of its bioactive fractions, in a concept of circular economy and sustainability. [ABSTRACT FROM AUTHOR]

In this study, the solubilization and structural changes of lignin in naked oat stems were investigated under subcritical water autohydrolysis systems (170–210 °C, 0.68–1.85 MPa). In this system, Hemicellulose was preferentially hydrolyzed in the liquid water at elevated temperatures, leading to the production of acetic acid and glucuronic acid, which acidified the reaction system. Under acidic and high-temperature conditions, lignin primarily underwent degradation and condensation reactions. At autohydrolysis temperatures below 190 °C and autohydrolysis pressures below 1.22 MPa, lignin degradation was predominant, realizing a maximum lignin removal of 47.8 % and breakage of numerous β-O-4 bonds from lignin. At autohydrolysis temperatures above 190 °C and autohydrolysis pressures above 1.22 MPa, lignin condensation dominated, with an increase in the amount of organic acids generated upon hemicellulose degradation, leading to condensation reactions with the degraded low-molecular-weight lignin. The degree of lignin condensation was positively correlated with the temperature of the reaction system. This study provides essential insights into the dynamic changes in the structure of lignin in both the hydrolysis residue and hydrolysis solution during subcritical water autohydrolysis. [ABSTRACT FROM AUTHOR]

Herein, cellulose nanocrystals were synthesized from oil palm fronds (CNC-OPF) involving two pretreatment approaches, viz. autohydrolysis and soda pulping. The pretreatments were applied individually to OPF fibers to assess their influence on CNCs' physicochemical and thermal properties. CNC-OPF samples were assessed using complementary characterization techniques, which confirmed their purity and characteristics. CP/MAS 13C NMR and TEM studies revealed that autohydrolysis pretreatment yielded CNCs with effective hemicellulose and extractives removal compared to that of soda pulping. XRD analysis demonstrated that autohydrolysis-treated CNC-OPF contained a much higher crystallinity index compared to soda pulping treatment. BET measurement disclosed a relatively higher surface area and wider pore diameter of autohydrolysis-treated CNC-OPF. Autohydrolysis-treated CNCs were applied as a reinforcement filler in alginate-based hydrogel beads for the removal of 4-chlorophenol from water, which attained a q max of 19.168 mg g−1. BET analysis revealed the less porous nature of CNC-ALG hydrogel beads which could have contributed to hydrogel beads' relatively lower adsorption capacity. The point of zero charge of CNC-ALG hydrogel beads was 4.82, suggesting their applicability only within a short solution pH range. This study directs future studies to unveil the possibilities of functionalizing CNCs in order to enhance the adsorption performance of CNC-immobilized hydrogel beads towards 4-chlorophenol and other organic contaminants. [Display omitted] • Autohydrolysis and soda pulping pretreatments were assessed to characterize CNC-OPF. • Autohydrolysis yielded CNC-OPF with enhanced physicochemical and thermal properties. • Autohydrolysis-treated CNC-OPF were reinforced to prepare alginate-based beads. • OPF-derived CNC-alginate hydrogel beads revealed potential 4-CP adsorption capability. [ABSTRACT FROM AUTHOR]

Several lignocellulosic wastes are generated in the pulp and paper industry (PPI), such as small wood chips (pinchips) and paper sludge, presenting a high cellulose content suitable to be converted into biofuels or bio-products in a forest biorefinery scheme. In this work, two schemes of biorefinery were proposed for their valorization, processing small eucalyptus wood pinchips in two different strategies: (i) autohydrolysis at 230ºC, and (ii) autohydrolysis at 195ºC followed by organosolv process (47.7% ethanol-water, 198ºC for 60 min). More than 95% of cellulose was recovered in both schemes. In the combined process, 76% of delignification was achieved and 78% of xylan was solubilized as xylooligosaccharides. To reduce operational cost of lignocellulosic biomass-to-ethanol fermentation, the mixture of the treated eucalyptus pinchips from two processes with sludge was also proposed to increase the initial glucan content and to supply a rich source of nitrogen (present in the sludge). For that, two experimental designs were carried out for ethanol production by simultaneous saccharification and fermentation (SSF) process. Ethanol from SSF assays using sludge as co-substrate at 0.6 g of sludge/g of treated wood pinchips and 16 FPU/g of pretreated solids allowed to obtain 59 g/L (90% of conversion) and 46 g/L (96% of conversion) when blended with the wood from autohydrolysis and with the wood from autohydrolysis followed by organosolv, respectively. Overall, this study shows an alternative process valorization of biomasses derived from PPI for production of advanced biofuels and bio-products (such as xylooligosaccharides and lignin) contributing to achieving a circular economy. • Multi-waste valorization approach was proposed to produce biofuel and bioproducts. • Autohydrolysis and organosolv processes allowed > 90% glucan recoveries. • Higher than 40 g/L of ethanol and 90% of yield were obtained in both schemes developed. • Blending with sludge improve ethanol production from pretreated eucalyptus wood. [ABSTRACT FROM AUTHOR]

Two previous treatments have been applied to the ethanol-soda paste process on Eucalyptus globulus wood to evaluate its influence on the properties of the obtained cellulose pulps. The treatments consisted of a first optimized stage of autohydrolysis (temperature: 180 °C, time: 30 min) to obtain the maximum extraction rate of hemicellulosic derivatives preserving the glucan, followed by enzymatic oxidative delignification by a laccase/mediator system (syringaldehyde). Experimental designs have been applied for the optimization of processes. The optimum operating conditions in the enzymatic delignification stage were: Lacasse concentration 18,5 U/g, concentration of syringaldehyde 1,5 %, temperature 45 °C and operating time 60 min., with which an elimination of the 16,8% of the existing lignin in the raw material and slightly affects the glucan (it is conserved between 82,2 % and 89,7 % of the initial glucan). Two liquid, recoverable phases are obtained, rich in hemicellulose and polyphenolic derivatives. In this process scheme to obtain ethanol-soda cellulosic pulp from eucalyptus wood requires a lower concentration of chemical reagents, shorter operating times and lower temperatures, which is an economic and environmental improvement over the conventional pulping process. [ABSTRACT FROM AUTHOR]

An innovative approach for preparing hemp fibers from hemp hurds for use in tissue and towel grades of paper is described. Hemp hurds are a low value by-product of industrial hemp processing that are generally used for animal bed litter. Tissue paper was fabricated from hemp hurd fibers by following three pulping processes: autohydrolysis (hydrothermal), sodium carbonate-based defibration, and high yield kraft pulping, and benchmarked against hardwood pulp. To meet industrial standards, hardwood and hemp pulp fibers were mixed at a dry mass ratio of 75:25, from which tissue paper sheets were prepared. Desirable tissue paper properties, such as water absorption, burst resistance, softness, and tensile strength (dry and wet), were measured and compared. Characterization of morphological and chemical properties of tissue handsheets was conducted with SEM and time-of-flight-secondary ion mass spectrometry (ToF-SIMS). The combined kraft pulped hardwood and autohydrolyzed hemp pulp fibers displayed improvements in tensile index, burst resistance, and softness of tissue handsheets compared to only kraft hardwood pulp handsheets without adversely impacting water absorption. Hardwood fibers showed a sparse distribution of surface lignin compared to hemp fibers using the same defibration. This technology can lead to a variety of eco-friendly tissue paper products that are not only highly energy efficient, but avoid harsh chemical processing. [ABSTRACT FROM AUTHOR]

• Six brewer's spent grains (BSG) were characterized and compared for ethanol production. • Autohydrolysis at high solid loadings was carried out for BSG fractionation. • Autohydrolysis facilitated enzymatic hydrolysis of BSG using 25% of solid loading. • High concentration of glucooligosaccharides (51.6 g L−1) was obtained from BSG autohydrolysis. • High-gravity ethanol was produced from BSG whole slurry at high solid loadings. This work targets the valorization of brewer's spent grain (BSG) waste by ethanol production, providing strategies for increasing titers in the multiple process steps involved. High solid loadings and use of whole slurry from the pretreatment were evaluated, aiming to achieve high ethanol concentration and yield. As variability in BSG chemical composition presents a challenge for their valorization, six different BSGs were chemically characterized, which allowed the selection of two with high polysaccharide content. High solid loadings (up to 25%) were employed for the pretreatment of selected BSGs by autohydrolysis, an environmentally friendly process, to improve enzymatic saccharification and extract fermentable sugars as oligosaccharides and monosaccharides. As a result, high glucose concentrations (43.7 and 57.7 g L−1) and glucose yield (85.9 and 70.6%) were obtained from the saccharification of the pretreated BSG whole slurry at 20 and 25% solid loading, respectively. Whole slurries from autohydrolysis were used as substrate for ethanol production by hybrid saccharification and fermentation. Two different Saccharomyces cerevisiae strains were evaluated and high ethanol concentration (42.27 g L−1) at a high yield (94.0%) was achieved. The results attained by the combined intensification approaches qualify BSG waste as a valuable renewable resource for cost-effective ethanol production. [ABSTRACT FROM AUTHOR]

Sargassum muticum , an invasive macroalgae in Europe, was employed as material for third generation bioethanol production. As a first step, autohydrolysis was chosen as an eco-friendly pretreatment, seeking for a high enzymatic susceptibility of the solid phase and high content of hexoses as glucose, galactose and mannose, in both liquid and solid phases, which can be subsequently transformed in ethanol via fermentation. Besides, the search of a minimum consumption of energy in the pretreatment is also a key challenge in bioethanol production. At optimum conditions of autohydrolysis pretreatment, more than 90% of the glucan was recovered in the solid phase (while the other 10% appeared as glucooligosaccharides and glucose in the liquid phase). In the enzymatic hydrolysis carried out with the solid phases, glucan to glucose conversions of 94 and 89% were obtained, with the solid mixed with water and the whole slurry, respectively. Moreover, the whole slurry experiments, where all hexoses present in the raw material (glucose, galactose and mannose) from the solid and the liquid phases are fermented, allows to reach maximum ethanol yields of 80% (14.10 g of ethanol/L) referred to the theoretical yield, in a short time. • Autohydrolysis is a suitable pretreatment for bioethanol production from Sargassum. • Almost 100% of hexoses are recovered in the optimum conditions. • Glucan to glucose conversion above 90% was achieved in enzymatic hydrolysis assays. • SSF without nutrients reached 80–95% theoretical ethanol yield in less than 10 h. [ABSTRACT FROM AUTHOR]

Biorefining uses alternative resources (such as biomass) instead of petrochemical sources to produce bioenergy and platform chemicals. Walnut shell is a promising lignocellulosic biomass for the production of fermentable carbohydrates. In this study, the platform chemical L-(+) lactic acid was produced after walnut shell had been treated with physicochemical and biological processes. So biomass waste can be regenerated to the benefit of the circular bio-economy. Autohydrolysis assisted by microwave processes was used to depolymerize hemicellulose and amorphous cellulose in walnut shell to yield 63.5% w/w of xylose in a liquid fraction (hydrolysate) with a minimum yield of glucose. The optimum reaction conditions to obtain a high xylose yield with a low byproduct titer were 190 °C for 25 min. L-(+) lactic acid was produced by thermophilic Bacillus coagulans DSM 2314 with a carbon source of xylose and glucose which were solubilized in hydrolysate from autohydrolyzed walnut shell. A non-sterile and straightforward fermentation medium coupled with a pH adjustment of the crude hydrolysate in an anaerobic environment led to a L- (+) lactic acid yield of 81% w/w with a productivity of 0.2 g/L/h. Image 1 • Autohydrolysis assisted by microwave processes depolymerized hemicellulose. • Both physical and chemical impacts were revealed after autohydrolysis. • By-products in hydrolysate did not affect fermentation process. • 63.5 wt% of xylose yield was obtained from walnut shell's hemicellulose component. • Bacillus coagulans converted xylose and glucose into L- (+) lactic acid. [ABSTRACT FROM AUTHOR]

Lignin is a biopolymer usable in many ways once it has been separated and delignified from biomass. In this training report, delignification of coconut husk fibres is performed, with the aim of recovering isolated lignin. In order to do so, different processes are carried out (autohydrolysis, dilute acid, organosolv and soda pulping treatments). The obtained lignin is characterised afterwards through Fourier transform infrared (FTIR), 1H and 13C nuclear magnetic resonance (NMR) in order to check lignin presence and quality. Analyses show that lignin is indeed obtained in both experiments, though the yield is greater for the treatment with autohydrolysis. However, the global yield is quite low, adjustments of experimental parameters (time, temperature, ratio) shall be carried out. [ABSTRACT FROM AUTHOR]

Eucalyptus globulus wood samples were subjected to hydrothermal processing according to a three-stage, crossflow scheme with intercalated washing stages. The operational conditions for each hydrothermal stage were selected based on previous experiments, as the kinetics and yields depended on the composition of the reaction media. The solid recovery yields as well as the compositions of the various solids and liquids involved in each stage were measured, in order to allow the formulation of material balances. Under the conditions selected, the various stages enabled solid recovery yields in the range 70.8–74.4 g/100 g oven-dry wood, with extensive hemicellulose removal and almost quantitative recovery of both cellulose and lignin in solid phase. The production of valuable polysaccharide-derived products (including saccharides and furans) along the process decreased owing to the different initial composition of the various reaction media. In turn, the generation of monosaccharides from soluble saccharides of oligomeric or polymeric nature was promoted in the second and third stages. The experimental data provided in this study allow a quantitative assessment on the considered process, a basic information for simulation and economic evaluation. [ABSTRACT FROM AUTHOR]

Enzymatic hydrolysis accounts for 20% of the total cost in the conversion process of lignocellulosic biomass into bioethanol. Therefore, production of biomass-degrading enzymes by using lignocellulosic residue as a fermentation substrate may be an alternative to decrease the production costs. In this study, corncob (CC) has been pretreated by liquid hot water (LHW) at 200 °C for 30 min and used as inducer source for production of biomass-degrading enzymes by Trichoderma reesei MUM 97.53. The pretreatment was used to increase the cellulose content and the accessibility to lignocellulosic material. Although the filamentous fungus secreted a broad range of cellulolytic and hemicellulolytic enzymes when grown on untreated CC, higher enzyme productions were obtained when cultured on LHW-pretreated CC in a 2-L stirred tank bioreactor (STB). Besides, the effects of aeration (2 and 4 vvm) and agitation (150 and 250 rpm) rates on enzyme production were studied by submerged fermentation in a batch STB and correlated with the volumetric oxygen transfer coefficient (kLa). Maximal cellulase, xylanase, and β-xylosidase productions were found at 150 rpm and 4 vvm, while the highest β-glucosidase levels were obtained at 150 rpm and 2 vvm, that corresponded to kLa values of 32.50 h−1 and 16.41 h−1, respectively. At higher agitation, a lower enzymatic production was observed probably due to the high shear stress in the fungal hyphae. [ABSTRACT FROM AUTHOR]

Abstract The nut industries generate a high amount of by-products that can be valorized as feedstocks for new processes using green technologies. Hazelnut shells have potential as source of antioxidant compounds with commercial interest in cosmetic, pharmaceutical and food industries. Antioxidants from hazelnut shells can be solubilized in autohydrolysis processes and recovered using resins. The autohydrolysis study led to achieve the highest solid solubilization of 26.7 g of non-volatile compounds (NVC)/100 g of hazelnut shells at 220 °C. Higher temperatures improved the release of phenolic compounds in the aqueous phase up to 3.37 g of gallic acid equivalents (GAE)/100 g of hazelnut shells. The DPPH free radical scavenging capacity allowed to determine the potential activity of the extracted phenolic compounds, and increasing temperatures improved the antioxidant capacity of extracts up to 1.64 g GAE/100 g of NVC in the range 210–230 °C. The phenolic compounds in aqueous phase after autohydrolysis were recovered by adsorption, and the sorption kinetics and the equilibrium isotherms were evaluated. The maximum sorption capacities of assayed resins were 8.9 and 7.7 mg GAE/g resin for Amberlite XAD4 and XAD16HP, respectively. The knowledge provided for this study should be helpful to further exploit and apply phenolic compounds from hazelnut shells as source of natural antioxidant compounds. Highlights • Green processes for antioxidants recovery: Autohydrolysis followed by adsorption. • EC 50 close to 0.16 GAE/L was reached at 210 °C autohydrolysis treatment. • Phenolic yields were significantly improved by increasing temperatures. • The highest adsorption efficiency was provided by SP700 and XAD16HP resins. • Experimental kinetic data fitted with a pseudo-second order model. [ABSTRACT FROM AUTHOR]

• Multi-step pretreatment of pine using autohydrolysis and ionic liquid is proposed. • The autohydrolysis step hamper the subsequent ionic liquid pretreatment of pine. • Fractal dimension and laccunarity are related to enzymatic saccharification. • Surface composition is different to lobal composition of pretreated biomass. • The highest glucose yields is obtained with the sample AH150IL120. Sequential pretreatments provide advantages of every single process towards a complete biomass fractionation. In this work, autohydrolysis and IL microwave pretreatments are sequentialy studied, and their effect to enhance enzymatic hydrolysis is analyzed. Mild, intermediate and severe autohydrolysis are combined with four IL temperatures (50, 80, 120 and 150 °C). Pretreated solids are enzymatically hydrolyzed and compared in terms of chemical composition and morphology. Digital image analysis is employed to numerically determine the heterogeneity of the solids using surface fractal dimension and lacunarity parameters. In this study, the negative effect of intermediate and severe autohydrolysis, over the subsequent IL pretreatment is demonstrated. Mild autohydrolysis and high IL conditions (AH150IL120) results in digestibilities of 78.8 g of glucan/100 g of glucan introduced. High surface fractal values (in the range of 2.5461–2.7124) and low lacunarities (0.0818–0.2563) enhance the enzymatic accessibility of pine wood. Furthermore, the negative effect of softwood lignin accumulation in the surface is observed using confocal fluorescence microscopy. [ABSTRACT FROM AUTHOR]

• Xylan depolymerisation in a pretreatment continuous tubular reactor was analysed. • Autohydrolysis reactions described the xylan depolymerisation dynamics in the reactor. • Wheat straw, corn stover and sugar cane bagasse were used for experimental validation. • Wheat straw showed the highest production of oligosaccharides without degradation. This work proposes a mathematical model for describing the dynamics of xylan depolymerisation of lignocellulosic biomass in a pilot-scale pretreatment continuous tubular reactor. Xylan depolymerisation, modelled as pseudo-homogeneous first order reactions and mass flow dynamics, are described as a set of ordinary differential equations. The model accurately describes the dynamics of xylooligosaccharides and other depolymerisation products at the reactor output. Experimental validations of residence time distribution, mass flow rates and kinetics were carried out at 18 and 37 min of mean residence time for wheat straw, corn stover and sugar cane bagasse. Wheat straw exhibited the highest production of xylooligosaccharides (approximately 70%) without degradation at 37 min of residence time. [ABSTRACT FROM AUTHOR]

Autohydrolysis and kraft pulping were sequentially applied to Eucalyptus urograndis wood to obtain added-value products from hydrolysis liquor. A biorefinery approach was used to bleach the resulting solid phase containing the cellulose pulp with an optimized O-D-(EP)-D bleaching sequence, where O denotes delignification with the sequence D bleaching with chlorine dioxide and EP alkaline extraction with soda and hydrogen peroxide. The pulp was then beaten to obtain paper sheets. The two-stage process yielded pulp with a small Kappa number relative to conventional delignification (4.9 to 13.7 vs 17.1). Using autohydrolysis temperatures of 160 °C to 170 °C during 0 min to 15 min made the process selective towards the extraction of hemicelluloses (xylan up to 43.9%). Additionally, the Kappa number and brightness obtained after bleaching with an O-DEP-D sequence were suitable for preparing dissolving grade pulp. The brightness of the pulp obtained was identical with that of the reference pulp (91.0%) and the Kappa number was smaller (0.2 to 0.6). Beating the pulp for 4500 PFI revolutions produced paper sheets with slightly better tensile strength and tear index than those for sheets from the reference pulp (viz., 90.3 N·m·g-1 and 9.9 mN·m²·g-1, respectively, versus 89.8 N·m·g-1 and 9.7 mN·m²·g-1, respectively). [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Poplar sapwood chips were autohydrolyzed followed by an alkali impregnation. • Other chemical components had less impact on alkali impregnation than surface lignin. • Surface lignin had no effect on alkali impregnation compared to the volume porosity. • Autohydrolysis can facilitate chemi-mechanical pulping. Abstract Chemi-mechanical pulping, a typical high-yield pulping method, combined with autohydrolysis pretreatment prior to pulping is an efficient and value-added utilization method for biomass in pulp and paper industry. This study investigated the surface lignin changes of poplar sapwood chips in autohydrolysis pretreatment and their effect on the subsequent alkali impregnation for chemi-mechanical pulping. The results showed that the surface lignin content went up with the increase of autohydrolysis intensity, and that the existence of the surface lignin had nearly no impact on the subsequent alkali impregnation in making chemi-mechanical pulps (CMPs) compared to the volume porosity, which was validated by using the stepwise regression analysis. It can be further concluded that autohydrolysis can facilitate the subsequent alkali impregnation of the autohydrolyzed sapwood chips in making CMP, which would be of significance for the combination of biomass refinery and pulp and paper industry. [ABSTRACT FROM AUTHOR]