Comparative study of lignins isolated by alkali and ultrasound-assisted alkali extractions from wheat straw

Process Optimisation of Ultrasound-Assisted Extraction of Oligosaccharides from Coconut Husk

A fractional factorial design was used to investigate the ultrasound-assisted extraction (UAE) of oligosaccharides from coconut husk, an agroindustry by-product. The effects of five key influencing parameters (X ₁, incubation temperature; X ₂, extraction duration; X ₃, ultrasonicator power; X ₄, NaOH concentration; X ₅, solid-to-liquid ratio) were studied. Total carbohydrate content (TC), total reducing sugar (TRS), and degree of polymerisation (DP) were the dependent variables. The optimal extraction condition was attained when oligosaccharides with a desired DP of 3.72 were extracted when the coconut husk in a liquid-to-solid ratio of 127 mL/g was treated with 1.05 percent (w/v) of NaOH solution at an incubation temperature of 30.4°C for 5 min using an ultrasonicator power of 248 W. The optimised parameters for oligosaccharide extraction from coconut husk reported in this study could be useful for the effective isolation of these compounds for prebiotic research.

A Comparative Study of Pectin Green Extraction Methods from Apple Waste: Characterization and Functional Properties

Traditional methods of pectin extraction led to drop quality, yield, functional properties, and excessive time. The objective of our research is to produce high-quality pectin from apple pomace as food processing by-product. Four nonconventional methods of extraction (microwave, ultrasound, citric acid, and organic acid mixture (citric acid, ascorbic acid, and acetic acid)) were compared to conventional extraction of pectin in terms of yields, thermal behavior, functional groups, antioxidant activity, and functional properties. Citric acid extraction method gave the highest yield (22%) compared to other methods. The extraction of pectin by organic acid mixture maximized the galacturonic acid index to 87.58%;. Also, it was changed from structural into: compacted, multilaminated, and flaky surface compared to the other samples (more porous and hollow opening structural) as well as increased stability of pectin particles in colloids as a result of increasing the charge on particles to -59.42, beside its higher thermal stability of pectin behaviors, which reflected on improving all functional properties compared to the other methods. On the other side, microwave-extracted pectin had the highest antioxidant activity (3-4 times) compared to other extraction methods. In conclusion, extraction using organic acids, microwave, and ultrasonic led to improve the pectin quality and could be used in high-temperature food products, like bakery products.

Structural Properties and Hydrolysability of Paulownia elongate: The Effects of Pretreatment Methods Based on Acetic Acid and Its Combination with Sodium Sulfite or Sodium Sulfite

The effects of CH₃COOH and Na₂SO₃ pretreatment on the structural properties and hydrolyzability of fast-growing Paulownia elongate were investigated. Acetic acid increased cellulose’s crystallinity and hydrolyzability when combined with alkaline sodium sulfite and sodium hydroxide. The cellulose content increased by 21%, the lignin content decreased by 6%, and the product showed better enzymatic digestibility. With a cellulase dose of 30 FPU/g DM, after 72 h hydrolysis, the hydrolysis yields of glucose and xylose were 78% and 83%, respectively, which were 51% and 69% higher than those of untreated materials. When the enzyme dosage was 20 FPU/g DM, after 72 h hydrolysis, the hydrolysis yields of glucose and xylose were 74% and 79%, respectively. The high hydrolyzability, low enzyme loading, and high hydrolysis yield demonstrate the potential of the proposed system for producing platform sugars from fast-growing Paulownia elongate.

The Fractionation of Corn Stalk Components by Hydrothermal Treatment Followed by Ultrasonic Ethanol Extraction

The fractionation of components of lignocellulosic biomass is important to be able to take advantage of biomass resources. The hydrothermal–ethanol method has significant advantages for fraction separation. The first step of hydrothermal treatment can separate hemicellulose efficiently, but hydrothermal treatment affects the efficiency of ethanol treatment to delignify lignin. In this study, the efficiency of lignin removal was improved by an ultrasonic-assisted second-step ethanol treatment. The effects of ultrasonic time, ultrasonic temperature, and ultrasonic power on the ultrasonic ethanol treatment of hydrothermal straw were investigated. The separated lignin was characterized by solid product composition analysis, FT-IR, and XRD. The hydrolysate was characterized by GC-MS to investigate the advantage on the products obtained by ethanol treatment. The results showed that an appropriate sonication time (15 min) could improve the delignification efficiency. A proper sonication temperature (180 °C) can improve the lignin removal efficiency with a better retention of cellulose. However, a high sonication power 70% (840 W) favored the retention of cellulose and lignin removal.

Local Variations in Carbohydrates and Matrix Lignin in Mechanically Graded Bamboo Culms

The mechanical performance of bamboo is highly dependent on its structural arrangement and the properties of biomacromolecules within the cell wall. The relationship between carbohydrates topochemistry and gradient micromechanics of multilayered fiber along the diametric direction was visualized by combined microscopic techniques. Along the radius of bamboo culms, the concentration of xylan within the fiber sheath increased, while that of cellulose and lignin decreased gradually. At cellular level, although the consecutive broad layer (Bl) of fiber revealed a relatively uniform cellulose orientation and concentration, the outer Bl with higher lignification level has higher elastic modulus (19.59-20.31 GPa) than that of the inner Bl close to the lumen area (17.07-19.99 GPa). Comparatively, the cell corner displayed the highest lignification level, while its hardness and modulus were lower than that of fiber Bl, indicating the cellulose skeleton is the prerequisite of cell wall mechanics. The obtained cytological information is helpful to understand the origin of the anisotropic mechanical properties of bamboo.

ULTRASONIC DISINTEGRATION OF LIGNOCELLULOSE RAW MATERIALS AS A PRE-TREATMENT OF A SUBSTRATE FOR MICROBIOLOGICAL PRODUCTION OF BIOBUTANOL

Aim. The purpose of the study was to investigate the effect of ultrasonic disintegration on the lignocellulosic raw materials (biomass of the non-cereal part of rape) with its subsequent use as a substrate for the production of biobutanol. Methods. Butanol-producing strains and the biomass of the non-cereal part of rape Brassica napus were used in the present study. Ultrasonic disintegration of lignocellulosic raw materials was performed on the specially designed equipment. Results. The effect of ultrasonic disintegration on lignocellulosic raw materials was investigated for further application in biofuel production based on microbiological conversion. The possibility of using the obtained components after the pre-treatment of lignocellulose by ultrasonic disintegration as a substrate for the microbiological synthesis of butanol was shown. The highest accumulation of butanol (2.4 g/l) was obtained with the use of 5% dry matter content in the medium, 5 min treatment and the specific power of ultrasonic disintegration of 0.72 W/ml. Conclusions. The possibility of producer strains of the genus Clostridium to use cellulose in the fermentation process has been shown. When using ultrasonic disintegration for pretreatment of the non-cereal part of the biomass of rape, the accumulation of butanol increased by 3 folds.

Lignin Nanoparticles and Their Nanocomposites

Lignin nanomaterials have emerged as a promising alternative to fossil-based chemicals and products for some potential added-value applications, which benefits from their structural diversity and biodegradability. This review elucidates a perspective in recent research on nanolignins and their nanocomposites. It summarizes the different nanolignin preparation methods, emphasizing anti-solvent precipitation, self-assembly and interfacial crosslinking. Also described are the preparation of various nanocomposites by the chemical modification of nanolignin and compounds with inorganic materials or polymers. Additionally, advances in numerous potential high-value applications, such as use in food packaging, biomedical, chemical engineering and biorefineries, are described.

Solubilisation of fruits and vegetable dregs through surfactant mediated sonic disintegration: impact on biomethane potential and energy ratio

This study investigates the symbiotic effect of cetyltrimethylammonium bromide (CTAB) coupled with sonication of fruits and vegetable dregs (FVD) on disintegration and subsequent energy efficient methane production. The liquefaction of FVD experiments was conducted by varying dosage of surfactant from 0.001to 0.01 g/g SS for 60 min in mechanical shaker. The optimised dosage of surfactant was combined with sonication. Finally, the combined pretreatment and sole pretreatment were assessed using methane potential assay. The results revealed that at optimised conditions (sonication specific energy of 5400 kJ/kg TS, CTAB dosage of 0.006 g/g SS), the maximum liquefiable organics release rate and solids reduction of CTAB mediated sonic disintegration (CSD) were found respectively to be 27% and 17% more than the ultrasonic disintegration (16% and 10%). CSD was noticed to be superior than ultrasonic disintegration (UD) based on highest volatile fatty acid yield (2000 mg/L vs. 1250 mg/L) and biochemical methane potential (203 mL/g COD vs. 144 mL/g COD). CSD achieved energy ratio of 0.9 which is greater than ultrasonic disintegration energy ratio 0.4.

Ultrasonic Delignification and Microstructural Characterization of Switchgrass

This present study was undertaken to investigate the ultrasonic delignification of switchgrass (Panicum virgatum L.) and the effects of ultrasonic irradiation on the molecular and microstructure of switchgrass. We investigated this question using response surface methodology (RSM) featuring a four-factor, three-level Box–Behnken experimental design with acoustic power (120, 180, and 240 W), solid–solvent ratio (1/25, 1/20, and 1/15 g/mL), hammer mill screen size (1.6, 3.2, and 6.4 mm), and sonication time (10, 30, and 50 min) as factors, while delignification (%) was the response variable. The native and treated switchgrass samples were further characterized through crystallinity measurements and electron microscopy. The results of lignin analysis show that the percent delignification ranged between 1.86% and 20.11%. The multivariate quadratic regression model developed was statistically significant at p < 0.05. SEM and TEM micrographs of the treated switchgrass grinds resulted in cell wall disruption at the micro- and nano-scales. XRD analysis revealed a reduction in the mean crystallite size and crystallinity index from 15.39 to 13.13 Å and 48.86% to 47.49%, respectively, while no significant change occurred in the d-spacings. The results of this investigation show that ultrasonic irradiation induces chemical and structural changes in switchgrass, which could enhance its use for biofuel and bioproducts applications.

Effect of alkaline and sonication pretreatments on the rumen degradability of date palm seeds

The main objective of this research was to evaluate the effects of chemical treatment and sonication (ultrasound) processing on the fiber composition and rumen degradability of date palm seeds (DPS). In the first trial, the effects of incubation or sonication in 4% sodium hydroxide (NaOH) on DPS fiber content and ruminal degradability were evaluated. Relative to untreated seeds, the ruminal degradability of DPS neutral detergent fiber (NDF) and organic matter (OM) increased (P < 0.05) for the treated seeds and were highest (P < 0.05) for the sonicated seeds. Relative to untreated seeds, the hemicellulose and lignin content were lower (P < 0.05) for the sonicated seeds, while the cellulose content was higher (P < 0.05) for the incubated seeds. In the second trial, the effects of subjecting DPS to different sonication times (5, 10, 20, and 30 min) were evaluated. The degradability of seeds' NDF and OM were greater (P < 0.05) for the sonicated than unsonicated seeds. The highest NDF degradability was seen after 30 min sonication, whereas the OM degradability was not affected by sonication time (P > 0.05). In the third trial, the effects of subjecting DPS to sonication in different NaOH solutions (1%, 2%, 4% NaOH) were evaluated. Relative to untreated seeds, the rumen degradability of seeds' NDF and OM increased with all NaOH concentrations but was highest (P < 0.05) with the 4% NaOH. In conclusion, our results showed that treating DPS with 4% NaOH increased the seeds' ruminal degradability, and subjecting DPS to sonication further improved their degradability in the rumen.

Self-Templating Synthesis of 3D Hollow Tubular Porous Carbon Derived from Straw Cellulose Waste with Excellent Performance for Supercapacitors

A three-dimensional hollow tubular porous carbon (SCPC) was prepared from straw cellulose waste through a self-templating method combined with NaOH activation. Straw cellulose acts both as carbon source and structural template. The obtained SCPC exhibits a 3D hierarchical porous network structure. SCPC has a high specific surface area, a high mesoporosity ratio, and a low resistivity, which make it display excellent electrochemical performance for supercapacitors. SCPC showed a high specific capacitance of 312.57 F g^-1 in 6 m KOH at 0.5 A g^-1 , an excellent rate performance of 281.32 F g^-1 even at 15 A g^-1 , and an outstanding cyclic stability of 92.93 % capacitance retention after 20 000 cycles at 1 A g^-1 . SCPC-based supercapacitors can deliver an energy density of 8.67 Wh kg^-1 at a power density of 3.50 kW kg^-1 in 6 m KOH and an energy density of 28.56 Wh kg^-1 at a power density of 14.09 kW kg^-1 in 1 m Et₄ NBF₄ /PC, which demonstrates the possibility of applying SCPC in supercapacitors. This research not only offers a facile and sustainable method for the preparation of hierarchical porous carbon for electrochemical energy storage devices but also provides a highly efficient method for the utilization of biomass waste.

Multiple response optimization of alkaline pretreatment of sisal fiber (Agave sisalana) assisted by ultrasound

A procedure for the alkaline pretreatment of sisal fiber assisted by ultrasound was optimized to obtain a higher solubilization of hemicellulose and the removal of lignin with cellulose fraction maintenance. A full factorial design 2³ was used for the evaluation of the effects of the variables (sonication time, NaOH concentration, and sonication amplitude) on the pretreatment. The optimal values for the variables using the Doehlert matrix for the sonication time, NaOH concentration, and sonication amplitude were 27 min, 4.1% (m/v), and 50%, respectively. The X-ray diffractometry and scanning electron microscopy analyses, after pretreatment, showed changes in chemical structure and morphology due to the removal of 82% of hemicellulose and 86% of lignin from sisal fiber. The soft reaction conditions and relatively short times demonstrated the effectiveness of the combined action of ultrasound with alkaline pretreatment to improve the accessibility to cellulose in this important step of the ethanol production process from biomass.

Optimization of ultrasonic-assisted extraction of pigment from Dioscorea cirrhosa by response surface methodology and evaluation of its stability

Response surface methodology (RSM) was utilized to optimize the ultrasonic-assisted extraction (UAE) of Dioscorea cirrhosa pigment (DCP). The results demonstrated that the yield of DCP is the highest (32.27%) when acetone volume fraction is 74%, extraction time is 31 min, and the temperature is 54 °C. Next, the effects of pH, temperature, light, metal ions, reductants and oxidants on the stability of DCP were further evaluated to confirm the best storage conditions of DCP. The results showed that DCP should be stored at a wide pH range of 3 to 9, below 80 °C and away from light. Metal ions such as Fe2+, Fe3+, and Ti4+ can destabilize DCP, while K+, Al3+, Ca2+, Cu2+, Mg2+, and Zn2+ have little impact on DCP. Moreover, DCP showed good anti-reduction and poor anti-oxidization properties. These results might provide the basic data and theoretical guidance for the application of DCP.

Production of Flocculants, Adsorbents, and Dispersants from Lignin

Currently, lignin is mainly produced in pulping processes, but it is considered as an under-utilized chemical since it is being mainly used as a fuel source. Lignin contains many hydroxyl groups that can participate in chemical reactions to produce value-added products. Flocculants, adsorbents, and dispersants have a wide range of applications in industry, but they are mainly oil-based chemicals and expensive. This paper reviews the pathways to produce water soluble lignin-based flocculants, adsorbents, and dispersants. It provides information on the recent progress in the possible use of these lignin-based flocculants, adsorbents, and dispersants. It also critically discusses the advantages and disadvantages of various approaches to produce such products. The challenges present in the production of lignin-based flocculants, adsorbents, and dispersants and possible scenarios to overcome these challenges for commercial use of these products in industry are discussed.

Influence of pretreatment conditions on lignocellulosic fractions and methane production from grape pomace

The lignocellulosic structure of grape pomace requires the use of pretreatments facilitating microbial decomposition of the matter and enhancing methane production. In this study, the effects of various pretreatments (freezing, alkaline treatment using NaOH and NH₃, acid treatment using HCl, ultrasounds and pulsed electric fields) were examined in batch mode. The highest methane production (0.178Nm³kg^-1 of COD) was attained after alkaline treatment with 10% NaOH w/w dry basis, at 20°C and for 24h. This result is due to the degradation of more than 50% of lignin and about 22% of cellulose present in grape pomace. The coupling of this pretreatment with freezing at -20°C exhibited the highest methane production of 0.2194±0.0007Nm³kg^-1 of COD. When applied to a larger scale continuous digester, this coupled pretreatment increased methane production by about 27%, compared to the untreated samples, promoting the green valorization of the biomass.

Coproduction of lignin and glucose from vine shoots by eco-friendly strategies: Toward the development of an integrated biorefinery

The objective of this work was to study the suitability of the pretreated vine shoots as a source of lignin and to determine its structural features. The best conditions to achieve the aim of this work were 12% NaOH, 124°C and 105min, as they permitted a removal of 67.7% of the lignin present in the pretreated vine shoots and the obtaining of a solid with a 69.4% of glucan. This delignified solid was subjected to an enzymatic hydrolysis achieving a conversion of glucan to glucose close to 100%. The characterization of lignins extracted from pretreated vine shoots was carried out for the first time and the following techniques were employed: a quantitative acid hydrolysis, HPSEC, TGA, FTIR and Pyrolysis-GC/MS. With this proposal, products from the main fractions of the vine shoots (hemicellulosic oligosaccharides, lignin fragments and cellulosic substrates) could be obtained separately, being potentially suitable for further applications.

Ultrasound assisted citric acid mediated pectin extraction from industrial waste of Musa balbisiana

The objectives of the present work are to extract pectin from industrial waste of Musa balbisiana by ultrasound assisted citric acid mediated extraction method and optimization was done through central composite statistical experimental design under response surface methodology. The outcomes of this study exhibited that, process variables (ultrasound power, pH and extraction time) had considerable influence on the pectin extraction. Second order mathematical equation was constructed to predict the data through regression analysis. The optimal extraction process condition was ultrasound power of 323w, pH of 3.2, extraction time of 27min and SL (solid-liquid) ratio of 1:15g/ml. The mean experimental yield of pectin (8.99±0.018%) was fine accord among predicted yield of pectin (9.02%).

Recent updates on different methods of pretreatment of lignocellulosic feedstocks: a review

Lignocellulosic feedstock materials are the most abundant renewable bioresource material available on earth. It is primarily composed of cellulose, hemicellulose, and lignin, which are strongly associated with each other. Pretreatment processes are mainly involved in effective separation of these complex interlinked fractions and increase the accessibility of each individual component, thereby becoming an essential step in a broad range of applications particularly for biomass valorization. However, a major hurdle is the removal of sturdy and rugged lignin component which is highly resistant to solubilization and is also a major inhibitor for hydrolysis of cellulose and hemicellulose. Moreover, other factors such as lignin content, crystalline, and rigid nature of cellulose, production of post-pretreatment inhibitory products and size of feed stock particle limit the digestibility of lignocellulosic biomass. This has led to extensive research in the development of various pretreatment processes. The major pretreatment methods include physical, chemical, and biological approaches. The selection of pretreatment process depends exclusively on the application. As compared to the conventional single pretreatment process, integrated processes combining two or more pretreatment techniques is beneficial in reducing the number of process operational steps besides minimizing the production of undesirable inhibitors. However, an extensive research is still required for the development of new and more efficient pretreatment processes for lignocellulosic feedstocks yielding promising results.

Development and validation of ultrasound-assisted solid-liquid extraction of phenolic compounds from waste spent coffee grounds

In this current work, Box-Behnken statistical experimental design (BBD) was adopted to evaluate and optimize USLE (ultrasound-assisted solid-liquid extraction) of phytochemicals from spent coffee grounds. Factors employed in this study are ultrasonic power, temperature, time and solid-liquid (SL) ratio. Individual and interactive effect of independent variables over the extraction yield was depicted through mathematical models, which are generated from the experimental data. Determined optimum process conditions are 244W of ultrasonic power, 40°C of temperature, 34min of time and 1:17g/ml of SL ratio. The predicted values were in correlation with experimental values with 95% confidence level, under the determined optimal conditions. This indicates the significance of selected method for USLE of phytochemicals from SCG.

Lignin and Cellulose Extraction from Vietnam’s Rice Straw Using Ultrasound-Assisted Alkaline Treatment Method

The process of cellulose and lignin extraction from Vietnam’s rice straw without paraffin pretreatment was proposed to improve economic efficiency and reduce environmental pollution. Treatment of the rice straw with ultrasonic irradiation for 30 min increased yields of lignin separation from 72.8% to 84.7%. In addition, the extraction time was reduced from 2.5 h to 1.5 h when combined with ultrasonic irradiation for the same extraction yields. Results from modern analytical methods of FT-IR, SEM, EDX, TG-DTA, and GC-MS indicated that lignin obtained by ultrasound-assisted alkaline treatment method had a high purity and showed a higher molecular weight than that of lignin extracted from rice straw without ultrasonic irradiation. The lignin and cellulose which were extracted from rice straw showed higher thermal stability with 5% degradation at a temperature of over 230°C. The ultrasonic-assisted alkaline extraction method was recommended for lignin and cellulose extraction from Vietnam’s rice straw.

Enhancing biogas plant production using pig manure and corn silage by adding wheat straw processed with liquid hot water and steam explosion

BACKGROUND

Pig manure utilization and valorization is an important topic with tightening regulations focused on ecological and safety issues. By itself pig manure is a poor substrate for biogas production because of its excessive nitrogen content relative to available organic carbon. Such substrate is alkaline, and methanogenesis can be suppressed, and so additional substrates with high organic carbon must be added. The most promising is straw, which is available from adjacent biogas plant cultures. However, the abundant lignocellulosic biomass of wheat straw undergoes slow decomposition, and only a fraction of the chemical energy can be converted into biogas; thus economical methods for pretreatment increasing bioavailability are sought.

RESULTS

A method was investigated to increase the methane yield in a full-scale plant for co-fermenting pig manure with corn silage, which was the default substrate in the original source reactors. Increased lignocellulosic bioavailability of wheat straw was achieved by combining liquid hot water (LHW) and steam explosion (SE). According to FT-IR analysis, the treatment resulted in hemicellulose hydrolysis, partial cellulose depolymerization, and lignin bond destruction. Low-mass polysaccharides (0.6 × 10³ g mol^-1) had significantly higher concentration in the leachate of LHW-SE wheat straw than raw wheat straw. The methanogenic potential was evaluated using inoculum from two different biogas plants to study the influence of microorganism consortia. The yield was 24-34% higher after the pretreatment process. In a full-scale biogas plant, the optimal conditions were ~ 165 °C, ~ 2.33 MPa, and 10 min in LHW and ~ 65 °C and ~ 0.1 MPa for SE. The processes did not generate detectable inhibitors according to GC-MS analysis, such as furfural and 5-hydroxymethylfurfural.

CONCLUSIONS

The LHW-SE combined pretreatment process increases the bioavailability of carbohydrates from wheat straw. The LHW-SE treated wheat straw gave similar biogas yields to corn silage, thus enables at least partial replacement of corn silage and is good for diversification of substrates. Surprisingly, microorganisms consortia from other biogas plant fed with other substrates may have higher efficiency in utilization of tested substrate. Thus, methanogenic consortia may be considered in the process of optimization at industrial scale. The efficiency was calculated, and the LHW-SE may be profitable at full industrial scale and further optimization is proposed.

Ultrasound assisted extraction of pectin from waste Artocarpus heterophyllus fruit peel

Four factors three level face centered central composite response surface design was employed in this study to investigate and optimize the effect of process variables (liquid-solid (LS) ratio (10:1-20:1ml/g), pH (1-2), sonication time (15-30min) and extraction temperature (50-70°C)) on the maximum extraction yield of pectin from waste Artocarpus heterophyllus (Jackfruit) peel by ultrasound assisted extraction method. Numerical optimization method was adapted in this study and the following optimal condition was obtained as follows: Liquid-solid ratio of 15:1ml/g, pH of 1.6, sonication time of 24min and temperature of 60°C. The optimal condition was validated through experiments and the observed value was interrelated with predicted value.

Performance assessment of activated carbon supported catalyst during catalytic wet oxidation of simulated pulping effluents generated from wood and bagasse based pulp and paper mills

The present study reports the performance of catalytic wet oxidation (CWO) for the treatment of simulated pulping effluents (with chemical oxygen demand (COD) = 15 000 and 17 000 mg L⁻¹) from large and small scale pulp and paper mills, respectively.

Potential of rice straw for bio-refining: An overview

The biorefinery approach for the production of fuels and chemicals is gaining more and more attraction in recent years. The major advantages of biorefineries are the generation of multiple products with complete utilization of biomass with zero waste generation. Moreover the process will be economically viable when it targets low volume high value products in addition to high volume low value products like bioethanol. The present review discuss about the potential of rice straw based biorefinery. Since rice is a major staple food for many Asian countries, the utilization of the rice straw residue for fuel and chemicals would be very economical. The review focuses the availability and the potential of this residue for the production of fuel and other high value chemicals.

Effects of Ultrasound on the Physicochemical Properties and Antioxidant Activities of Chestnut Polysaccharide

A comparison of chestnut polysaccharide extraction using ultrasound-assisted extraction (UAE) and hot water extraction (HWE) demonstrated that UAE is superior to HWE due to its higher extraction efficiency. Scanning electron microscopy (SEM), thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the ultrasound-assisted-extracted polysaccharide (UAEP) and hot water-extracted polysaccharide (HWEP). SEM images revealed that the UAEP and chestnut residue were crushed, with particle sizes that were smaller than those of the HWEP, which was related to the breakage of long-chain polysaccharides. TGA-DSC showed a higher transition temperature and enthalpy value for the UAEP than the HWEP, and the FTIR spectrum revealed typical characteristics of polysaccharides, with some differences between the UAEP and HWEP. The evaluation of antioxidant activities showed that the UAEP had stronger antioxidant capacities than the HWEP, regardless of the reducing power and DPPH-, ABTS- and hydroxyl radical-scavenging activities, suggesting that ultrasound is an optimal method to rapidly extract chestnut polysaccharide, a potential natural antioxidant.

Pretreatment combining ultrasound and sodium percarbonate under mild conditions for efficient degradation of corn stover

Ultrasound (US) can be used to disrupt microcrystalline cellulose to give nanofibers via ultrasonic cavitation. Sodium percarbonate (SP), consisting of sodium carbonate and hydrogen peroxide, generates highly reactive radicals, which cause oxidative delignification. Here, we describe a novel pretreatment technique using a combination of US and SP (US-SP) for the efficient saccharification of cellulose and hemicellulose in lignocellulosic corn stover. Although US-SP pretreatment was conducted under mild condition (i.e., at room temperature and atmospheric pressure), the pretreatment greatly increased lignin removal and cellulose digestibility. We also determined the optimum US-SP treatment conditions, such as ultrasonic power output, pretreatment time, pretreatment temperature, and SP concentration for an efficient cellulose saccharification. Moreover, xylose could be effectively recovered from US-SP pretreated biomass without the formation of microbial inhibitor furfural.

Effect of frequency and reaction time in focused ultrasonic pretreatment of energy cane bagasse for bioethanol production

Pretreatment of lignocellulosic biomass is a critical steps in bioethanol production. Ultrasonic pretreatment significantly improves cellulose hydrolysis increasing sugar yields, but current system designs have limitations related to efficiency and scalability. This study evaluates the ultrasonic pretreatment of energy cane bagasse in a novel scalable configuration and by maximizing coupling of ultrasound energy to the material via active modulation of frequency. Pretreatment was conducted in 28% ammonia water mixture at a sample:ammonia:water ratio of 1:0.5:8. Process performance was investigated as a function of frequency (20, 20.5, 21kHz), reaction time (30, 45, 60min), temperature, and power levels for multiple combinations of ammonia, water and sample mixture. Results indicated an increased enzymatic digestibility, with maximum glucose yield of 24.29g/100g dry biomass. Theoretical ethanol yields obtained ranged from 6.47 to a maximum of 24.29g/100g dry biomass. Maximum energy attainable was 886.34kJ/100g dry biomass.

Mechanistic study on ultrasound assisted pretreatment of sugarcane bagasse using metal salt with hydrogen peroxide for bioethanol production

This study presents the ultrasound assisted pretreatment of sugarcane bagasse (SCB) using metal salt with hydrogen peroxide for bioethanol production. Among the different metal salts used, maximum holocellulose recovery and delignification were achieved with ultrasound assisted titanium dioxide (TiO2) pretreatment (UATP) system. At optimum conditions (1% H2O2, 4 g SCB dosage, 60 min sonication time, 2:100 M ratio of metal salt and H2O2, 75°C, 50% ultrasound amplitude and 70% ultrasound duty cycle), 94.98 ± 1.11% holocellulose recovery and 78.72 ± 0.86% delignification were observed. The pretreated SCB was subjected to dilute acid hydrolysis using 0.25% H2SO4 and maximum xylose, glucose and arabinose concentration obtained were 10.94 ± 0.35 g/L, 14.86 ± 0.12 g/L and 2.52 ± 0.27 g/L, respectively. The inhibitors production was found to be very less (0.93 ± 0.11 g/L furfural and 0.76 ± 0.62 g/L acetic acid) and the maximum theoretical yield of glucose and hemicellulose conversion attained were 85.8% and 77%, respectively. The fermentation was carried out using Saccharomyces cerevisiae and at the end of 72 h, 0.468 g bioethanol/g holocellulose was achieved. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis of pretreated SCB was made and its morphology was studied using scanning electron microscopy (SEM). The compounds formed during the pretreatment were identified using gas chromatography-mass spectrometry (GC-MS) analysis.

Ultrasound-assisted bioalcohol synthesis: review and analysis

The present article highlights the efficacy of ultrasound in the intensification of all the steps of bioalcohol synthesis with a critical analysis of the literature.

Multivariate statistical analysis and optimization of ultrasound-assisted extraction of natural pigments from waste red beet stalks

In this study, ultrasound-assisted extraction (UAE) of natural pigment extraction from waste red beet stalks were optimized under four factors (extraction temperature, ultrasonic power, extraction time and solid-liquid ratio) by using three level Box-Behnken response surface design. Extraction temperature, ultrasonic power and solid-liquid ratio were significantly influenced the extraction yield of pigments. Extraction temperature of 53 °C, ultrasonic power of 89 w, extraction time of 35 min and SL ratio of 1:19 g/ml was identified as the optimal condition. Under this condition, the actual yield of (betacyanin of 1.28 ± 0.02 and betaxanthin of 5.31 ± 0.09 mg/g) pigments was well correlated with predicted values (betacyanin was 1.29 mg/g and betaxanthin was 5.32 mg/g).

Prospects for Irradiation in Cellulosic Ethanol Production

Second generation bioethanol production technology relies on lignocellulosic biomass composed of hemicelluloses, celluloses, and lignin components. Cellulose and hemicellulose are sources of fermentable sugars. But the structural characteristics of lignocelluloses pose hindrance to the conversion of these sugar polysaccharides into ethanol. The process of ethanol production, therefore, involves an expensive and energy intensive step of pretreatment, which reduces the recalcitrance of lignocellulose and makes feedstock more susceptible to saccharification. Various physical, chemical, biological, or combined methods are employed to pretreat lignocelluloses. Irradiation is one of the common and promising physical methods of pretreatment, which involves ultrasonic waves, microwaves, γ-rays, and electron beam. Irradiation is also known to enhance the effect of saccharification. This review explains the role of different radiations in the production of cellulosic ethanol.

Efficient combination of circulating ultrasound-assisted extraction and centrifugal partition chromatography for extraction and on-line separation of chemical constituents from Stellera chamaejasme L

INTRODUCTION

Sample preparation is a crucial step in medicinal herb analysis because the desired chemical components need to be extracted from the herbal materials for further separation and characterisation. Thus, the development of " modern" sample preparation techniques with significant advantages over conventional methods is very important.

OBJECTIVE

The aim of this study was the development of a new preparation method using circulating ultrasonic-assisted extraction (CUAE) coupled with centrifugal partition chromatography (CPC) for continuous extraction and on-line isolation of chemical constituents from Stellera chamaejasme L.

METHODOLOGY

The stationary or mobile phase was used as the extraction solvent. Extraction parameters, including the ultrasound power, extraction time, temperature, and liquid:solid ratio, were optimised using a response surface methodology.

RESULTS

The extraction time, temperature, and power considerably affected the extraction yield. The optimised extraction parameters were an ultrasound power of 800 W, extraction time of 30 min, extraction temperature of 70 °C, and liquid:solid ratio of 8 mL/g. The solvent system for CUAE and CPC was optimised using mathematical equations, and the two-phase solvent system of n-hexane:ethyl acetate:methanol:water at a volume ratio of 3:5:4:6 was calculated. Four target compounds (daphnoretin, chamaechromone, neochamaejasmin A, and isochamaejasmin) with purities above 96% were successfully extracted and isolated on-line via CUAE/CPC.

CONCLUSION

Compared with the reference extraction methods, the instrumental setup achieved a scientific and systematic extraction and isolation of natural products and has great potential for industrial application.