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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]

Enzymatic blends produced by fungal monocultures and consortia cultured in solid-state fermentation (SSF), using sugarcane bagasse (SB) and wheat bran as substrates (1:1, w/w), were evaluated for saccharification of sugarcane bagasse pretreated by autohydrolysis (hydrothermal pretreatment—HP) and alkaline delignification (HP-Soda). The highest glucose releases were obtained after saccharifications of SB pretreated by HP using enzyme cocktails produced by Aspergillus niger and by the consortium among A. fumigatus, Ganoderma lucidum and Trametes versicolor, with 10.8 and 9.8 g L−1, respectively. For SB pretreated by HP-Soda, the hydrolysate 10 (extract from A. niger, G. lucidum and Pleurotus ostreatus consortium) achieved maximal glucose concentration (11.92 g L−1). After alcoholic fermentation of the hydrolysates, the greatest ethanol yield in relation to the maximum theoretical yield (60.8%) was obtained in the fermentation of hydrolysate 1 (A. niger) obtained from SB pretreated by HP-Soda. These results demonstrated that on-site produced enzyme cocktails can be applied for saccharification of pretreated sugarcane bagasse and also contribute to cost reduction of bioconversion processes. [ABSTRACT FROM AUTHOR]

Three concepts for a 3000 t/a continuous autohydrolysis plant aiming at a full fractionation of agricultural residues (wheat straw as model substrate) into streams rich in xylose, glucose, and lignin, respectively, are developed. For this purpose, two kinetic models based on batch liquid-hot water experiments (30 mL, 170–230 °C, 10–60 min) were investigated. The solid hemicellulose conversion was described with a first-order rate model. The concentration and conversion profile investigation of the solid and liquid phases using the severity factor resulted in a linear equation describing the hemicellulose solubilization: XHC = (0.5839 ∗ log(R0) − 1.7027) ± 0.06. Here, specific process parameter boarders for the maximal hemicellulose concentration and furfural formation at log(R0) = 4.0 considering the liquid phase were identified. These findings were used to propose a multi-step hydrothermal processing approach, with intermediate sugar extraction, tailored to the compositional requirements of the product streams. Seven reactor types were evaluated for its feasibility; in this regard, the screw conveyor reactor (SCR) was evaluated as most promising. For the concepts, the SCR reactors were scaled, based on the generated data. It was found that the process temperature is a major parameter determining the reactor size. It is considered more important than the number of autohydrolysis treatment steps. In brief, the fractionation of agricultural residues using a multi-step continuous plant is evaluated to be very promising for the industrial application, regarding selectivity, handling, investment, and process costs. [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]

Abstract Background The acid buffering capacity of high free ash in waste wheat straw (WWS) has been revealed to be a significant hindrance on the efficiency of autohydrolysis pretreatment. Previous researches have mainly relied on washing to eliminate the influence of ash, and the underlying mechanism of the ash influencing was not extensively investigated. Presently, studies have found that cations can destroy the acid buffering capacity of ash through cation exchange. Herein, different cations were applied to presoak WWS with the aim to overcome the negative effects of ash on autohydrolysis efficiency, further improving its enzymatic digestibility. Results Results showed that cations can be adsorbed on the surface of the material by electrostatic adsorption to change the acid buffering capacity of WWS. The acid buffering capacity of 120 mM Fe2+ presoaked WWS is reduced from 226.3 mmol/pH-kg of original WWS to 79.3 mmol/pH-kg. This reduced the autohydrolysis pretreatment medium pH from 5.7 to 3.8 and promoted the removal of xylan from 61.7 to 83.7%. In addition, the enzymatic digestibility of WWS was enhanced from 49.7 to 86.3% by presoaking with 120 mM Fe2+ solution. The relationship between enzymatic accessibility and hydrophobicity with enzymatic digestibility of the autohydrolyzed WWS was analyzed. Conclusions The results showed that the acid buffering capacity of the high free ash was detrimental for the autohydrolysis efficiency of WWS. After WWS was presoaked with different cations, the acid buffering capacity of ash was weakened by cation exchange and electrostatic adsorption, which improved the autohydrolysis efficiency. The results expound that the enzymatic digestibility of WWS can be enhanced through presoaking to reduce the ash-influencing effect on autohydrolysis.

Novel personal care products are necessary to cope with the growing market demand for sustainable green products. In this context, this work deals with the formulation and fundamental physicochemical and rheological characterization of different natural personal care products using bioactive fractions from Chondrus crispus red macroalgae extracted under optimized green conditions. Body milks, body oils and shampoos were supplemented with soluble extracts with antioxidant features recovered after hydrothermal (200 °C) and microwave (170 °C)- and ultrasound (80 °C)-assisted extraction of the red macroalgae used as raw material. Formulated products were also compared with those prepared using (±)-α-tocopherol and butylhydroxytoluene standards. Body scrubs were formulated with the remaining solids (2–105 mPa s, at 1 s−1), comparable with their synthetic counterparts. To conclude, the addition of antioxidant extracts led to lower apparent viscosity values suggesting an advantage from the skin applicability point of view, jointly with the absence of both the hysteresis phenomenon and water syneresis of the proposed formulations.

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.

The leaves and petioles of Paulownia elongata x fortunei are residual fractions from the tree plantations commercially destined to the production of wood and their valorization could contribute to the rational utilization of this resource. The saccharidic fraction is the most abundant in both parts of the plant and the sugar profile is very similar, but the ethanol extractives are more abundant in leaves. Non isothermal processing was selected since it provided better results than isothermal extraction with shorter times. For this reason, optimization of autohydrolysis under non isothermal operation (140–240 °C) was performed for both materials: leaves and petioles. The final autohydrolysis temperature highly influenced the saccharidic, proteic, phenolic and volatile composition of the extracts. Operating under selected conditions leaves provided extracts with more antioxidant compounds than petioles. The proposed technology provides a variety of commercially valuable components, which could contribute to the integral use of this energetic crop following a biorefinery approach. [ABSTRACT FROM AUTHOR]

Pretreatment with efficient fractionation, eco‐friendliness, and low‐cost brings high security to future biorefinery systems. Synergistic pretreatment is a compelling blueprint to tackle the compact structure of lignocellulose towards a high‐level valorization. Here, a stepwise approach was designed using hydrothermal and deep eutectic solvent (DES) pretreatments to hierarchically extract hemicelluloses and lignin from poplar, while delivering a cellulose‐rich substrate that could easily undergo enzymatic hydrolysis to obtain fermentable glucose and residual lignin. The lifetime of recyclable DES showed that the pretreatment efficiency was still largely maintained after the fourth recycling. An enhancement of enzymatic digestibility from 13.9 to 90.4 % was initiated by the deconstruction of amorphous portions and robust cell wall. 23.7 % Xylooligosaccharides (degree of polymerization 2–6), 47.5 % DES‐isolated lignin, and 19.2 % cellulose enzymatic lignin were harvested via this coupled process. This study could promote the precise design of sustainable tandem pretreatment that can boost the frontier of highly available biorefinery. [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]

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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]

Olive table industry, olive mills and olive pomace oil extraction industries annually generate huge amounts of olive stones. One of their potential applications is the production of bioethanol by fractionation of their lignocellulose constituents and subsequent fermentation of the released sugars using yeasts. In this work, we studied the influence of temperature (175–225 °C) and residence time (0–5 min) in the liquid hot-water pre-treatment of olive stones as well as the initial enzyme loading (different mixtures of cellulases, hemicellulases and β–glucosidases) in the later enzymatic hydrolysis on the release of fermentable sugars. The Chrastil’s model was applied to the D-glucose data to relate the severity of pre-treatment to enzyme diffusion through the pre-treated cellulose. Finally, the hydrolysate obtained under the most suitable conditions (225 °C and 0 min for pre-treatment; 24 CE initial enzyme concentration) was fermented into ethanol using the yeast Pachysolen tannophilus ATCC 32691. Considering the overall process, 6.4 dm3 ethanol per 100 kg olive stones were produced. [ABSTRACT FROM AUTHOR]

While bond formation has historically been the mainstay of medicinal chemistry, the phenomenon of bond cleavage has received less focus. However, the success of numerous oral medications demonstrates the importance of controlled cleavage in prodrugs to achieve desired therapeutic outcomes. Nevertheless, effective strategies to control this cleavage remain limited. This concept article introduces a novel approach: employing peptides as conjugates to drugs to modulate the hydrolysis of these conjugates and enhance drug efficacy. The article begins by briefly outlining common prodrug strategies, followed by a few representative examples of how peptides can be leveraged to control the autohydrolysis of peptide-conjugated prodrugs for bacterial and cancer cell inhibition. Finally, it provides a brief outlook on the future potential of this promising new research direction in molecular medicine., (© 2024 The Authors. ChemMedChem published by Wiley-VCH GmbH.)

• 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]

The brown seaweed Sargassum muticum was processed by non isothermal autohydrolysis under conditions selected to maximize fucoidan solubilization (170 °C). Acetone precipitation was tried for recovery of fucose-containing oligosaccharides present in hydrolyzates. The acetone:hydrolyzate volume ratio influenced both yields and composition of the precipitated fractions. The sugar components were mostly found as oligomers, their content increased with acetone:hydrolyzate volume ratio 2.0 (v/v) exhibited slight. The fractions precipitated with 0.1 and 0.9 acetone volumes showed higher phenolic and sulfate content, which was positively correlated with the antiradical activity, and exhibited slightly cytotoxic activity against human colon adenocarcinoma cells. The highest volumes of acetone used led to a slight increase in the apparent viscosity as well as the elastic and viscous moduli of formulated aqueous dispersions of alginate. Steady-state and oscillatory shear measurements of above representative dispersions indicated that the alginate extracted after acetone precipitation exhibited a slight enhancement of the viscoelastic features. [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]

This study deals with the development and mechanical characterization of innovative starch- and gelatin-based hydrogels enriched with hydrothermal aqueous extracts from Paulownia (i.e., bark, leaves, petioles). The color, rheology, and texture properties of formulated biopolymer-based hydrogels depending on the processing conditions of the extracts was evaluated for the different Paulownia fractions. Results indicated that a clear impact on color features of the tested hydrogels was observed with the incorporation of Paulownia extracts. Rheological testing showed that weak and intermediate strength hydrogels were identified for starch- and gelatin-based hydrogels independently of used extract. A relevant softening of all gelled matrices was observed in the presence of recovered liquor extracts involving the following trend (leaves > barks > petioles). For all fractions, the highest viscoelastic features were achieved for hydrogels made with extracts recovered at 140 °C. Texture outcomes confirmed the rheological achievements. No syneresis was observed in developed hydrogels after two weeks of cold storage. [ABSTRACT FROM AUTHOR]

Xylooligosaccharides (XOS) production from sweet sorghum bagasse (SSB) has been barely studied using other edible biomasses. Therefore, we evaluated the XOS content as well as its purity by comparing the content of total sugars from SSB. An environmentally friendly approach involving autohydrolysis was employed, and the reaction temperature and time had variations in order to search for the conditions that would yield high-purity XOS. After autohydrolysis, the remaining solid residues, the glucan-rich fraction, were used as substrates to be enzymatically hydrolyzed for glucose conversion. The highest XOS was observed for total sugars (68.7%) at 190 °C for 5 min among the autohydrolysis conditions. However, we also suggested two alternative conditions, 180 °C for 20 min and 190 °C for 15 min, because the former condition might have the XOS at a low degree of polymerization with a high XOS ratio (67.6%), while the latter condition presented a high glucose to total sugar ratio (91.4%) with a moderate level XOS ratio (64.4%). Although it was challenging to conclude on the autohydrolysis conditions required to obtain the best result of XOS content and purity and glucose yield, this study presented approaches that could maximize the desired product from SSB, and additional processes to reduce these differences in conditions may warrant further research. [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]

The aim of this study was to clarify the role of the relative amounts of hemicelluloses and lignin on the enzymatic hydrolysis of pretreated sugarcane bagasse, by using the glucans/lignin ratio and the glucans/xylans ratio as a quick estimation of the enzymes accessibility to cellulose. The samples were selected to contain about 3–20% lignin, 52–90% glucans, and 6–26% xylans (by extraction of hemicelluloses and delignification). The enzyme loads used for saccharification were 10 FPU of cellulases and 20 IU of β-glucosidases per gram of samples. Conversions of glucans to glucose were highly influenced by the chemical composition, varying between 18.1% and 83.4%. The concentration of lignin and xylans in the pretreated bagasse affects the conversion to glucose. High conversions are achieved when the substrates are highly delignified. Less delignified samples can also lead to high conversion when the percentage of xylans are also decreased. Thus, the removal of both lignin and xylans contributes to an increase in the accessibility of cellulases to cellulose. [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]

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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]

Subcritical water extraction of Himanthalia elongata and the subsequent acetone fractionation to precipitate crude fucoidans generated a liquid phase which was used to recover alginates with a wide range of viscoelastic features and other soluble extracts with potential biological activities. The precipitated alginate was converted to sodium alginate using an environmentally friendly treatment before being characterized by Fourier transform infrared attenuated total reflectance, nuclear magnetic resonance, high performance size exclusion chromatography and rheological measurements. The cell viability of three human cell lines (A549, HCT-116, T98G) in the presence of the extracts obtained before and after acetone fractionation was assessed. Fractionation with different acetone volumes showed a slight effect in the behavior of the different tested cell lines. Results also indicated a notable effect of the processing conditions on the block structure and molar mass of the extracted biopolymer, with the subsequent impact on the rheological properties of the corresponding gelled matrices.

The integral valorization of artichoke bracts generated during industrial canning of artichoke was assessed. The extraction of bioactive compounds was addressed with pressurized hot water under subcritical conditions. The performance of this stage on the extraction of phenolics with antioxidant properties and the saccharidic fraction using conventional and microwave heating was compared. The microwave assisted process was more efficient than the conventional one regarding extraction yields of total solubles, and glucose and fructose oligomers and phenolics, because lower operational temperatures and shorter times were needed. Degradation of fructose oligomers was observed at temperatures higher than 160 °C, whereas the maximal phenolic content occurred at 220 °C. Both the extracts and the residual solids, obtained at conditions leading to maximum phenolics yields, were evaluated for the production of starch-based hydrogels, supplemented with Paulownia leaves’ aqueous extracts.

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]