Extraction Of Carbohydrates Research Articles

Effects of pH on steam explosion extraction of acetylated galactoglucomannan from Norway spruce

BackgroundAcetylated galactoglucomannan (AcGGM) is a complex hemicellulose found in softwoods such as Norway spruce (Picea abies). AcGGM has a large potential as a biorefinery feedstock and source of oligosaccharides for high-value industrial applications. Steam explosion is an effective method for extraction of carbohydrates from plant biomass. Increasing the reaction pH reduces the combined severity (R^{prime}_{0}) of treatment, affecting yields and properties of extracted oligosaccharides. In this study, steam explosion was used to extract oligosaccharides from Norway spruce wood chips soaked with sodium citrate and potassium phosphate buffers with pH of 4.0–7.0. Yields, monosaccharide composition of released oligosaccharides and biomass residue, their acetate content and composition of their lignin fraction were examined to determine the impact of steam explosion buffering on the extraction of softwood hemicellulose.ResultsReducing the severity of steam explosion resulted in lower yields, although the extracted oligosaccharides had a higher degree of polymerization. Higher buffering pH also resulted in a higher fraction of xylan in the extracted oligos. Oligosaccharides extracted in buffers of pH > 5.0 were deacetylated. Buffering leads to a removal of acetylations from both the extracted oligosaccharides and the hemicellulose in the residual biomass. Treatment of the residual biomass with a GH5 family mannanase from Aspergillus nidulans was not able to improve the AcGGM yields. No hydroxymethylfurfural formation, a decomposition product from hexoses, was observed in samples soaked with buffers at pH higher than 4.0.ConclusionsBuffering the steam explosion reactions proved to be an effective way to reduce the combined severity (R^{prime}_{0}) and produce a wide range of products from the same feedstock at the same physical conditions. The results highlight the impact of chemical autohydrolysis of hemicellulose by acetic acid released from the biomass in hydrothermal pretreatments. Lower combined severity results in products with a lower degree of acetylation of both the extracted oligosaccharides and residual biomass. Decrease in severity appears not to be the result of reduced acetate release, but rather a result of inhibited autohydrolysis by the released acetate. Based on the results presented, the optimal soaking pH for fine-tuning properties of extracted AcGGM is below 5.0.

Application of high-voltage electrical discharges and high-pressure homogenization for recovery of intracellular compounds from microalgae Parachlorella kessleri.

Treatments with high-voltage electrical discharges (HVED) and high-pressure homogenization (HPH) were studied and compared for the release of ionic components, carbohydrates, proteins, and pigments from microalgae Parachlorella kessleri (P. kessleri). Suspensions (1% w/w) of microalgae were treated by HVED (40kV/cm, 1-8ms) or by HPH (400-1200 bar, 1-10 passes). Particle-size distribution (PSD) and microscopic analyses were used to detect the disruption and damage of cells. HVED were very effective for the extraction of ionic cell components and carbohydrates (421mg/L after 8ms of the treatment). However, HVED were ineffective for pigments and protein extraction. The concentration of proteins extracted by HVED was just 750mg/L and did not exceed 15% of the total quantity of proteins. HPH permitted an effective release overall of intracellular compounds from P. kessleri microalgae including a large quantity of proteins, whose release (at 1200 bar) was 4.9 times higher than that obtained by HVED. Consequently, HVED can be used at the first step of the overall extraction process for the selective recovery of low-molecular-weight components. HPH can be then used at the second step for the recovery of remaining cell compounds.

Production of primary metabolites in Microcystis aeruginosa in regulation of nitrogen limitation

The aim of this work was to study the regulatory effect of nitrogen (N) deficiency on primary metabolites in Microcystis aeruginosa, and promote the utilization of the alga. Low-N and Non-N conditions, especially Non-N, reduced the cell growth and photosynthetic abilities compared to Normal-N, as N deficiency triggered the down-regulation of genes involving in the photosynthetic process. Non-N not changed lipid content, due to no up-regulation of genes that promoted lipid synthesis. Soluble protein content significantly decreased under Non-N, which may result from the declined expression of genes relating to amino acid and histidyl-transfer RNA synthesis. Soluble and insoluble carbohydrate content significantly increased under Non-N, as the expression variation of genes blocked sugar degradation and promoted lipopolysaccharide synthesis. Therefore, M. aeruginosa can be used as the feedstock to produce carbohydrates under N deficiency for bioethanol production, and the remainder lipids after carbohydrate extraction can be used to produce biodiesel.

Bio-oil production using residual sewage sludge after lipid and carbohydrate extraction

Bio-oil production using residual sewage sludge after lipid and carbohydrate extraction

Extraction and characterization of low molecular weight bioactive carbohydrates from mung bean (Vigna radiata)

Due to the great interest in obtaining natural bioactive carbohydrates to be used as functional ingredients, a selective microwave assisted extraction (MAE) method was optimized to ensure the exhaustive extraction of inositols and α-galactooligosaccharides (α-GOS) from mung bean. Thereafter, a comprehensive characterization of these compounds was carried out by gas chromatography coupled to mass spectrometry (GC–MS). Apart from free inositols and α-GOS, several glycosyl-methyl-scyllo-inositols and glycosyl-inositols were detected for the first time in this legume. Under optimized MAE conditions (0.5 g dry sample, 2 cycles of 3 min, 50 °C, 10 mL 50:50 ethanol:water, v:v), bioactive carbohydrates yields were similar to those found using solid–liquid extraction (SLE), but with shorter analytical times. Concentrations of bioactive carbohydrates in MAE extracts from samples of different geographical origins ranged between 74.1 and 104.2 mg.g−1 dry sample. MAE was proved a good alternative to SLE to obtain extracts enriched in bioactive carbohydrates.

Effect of pulsed electric fields and high pressure homogenization on the aqueous extraction of intracellular compounds from the microalgae Chlorella vulgaris

Pulsed Electric Fields (PEF) and High Pressure Homogenization (HPH) are promising and scalable cell disruption technologies of microalgae cells. In this work, the permeabilization degree, morphological properties, and extractability of intracellular compounds from microalgae Chlorella vulgaris suspensions (1.2%, w/w) were investigated as a function of PEF treatment at different electric field strengths (10–30 kV/cm) and total specific energy input (20–100 kJ/kg), in comparison with the more disruptive HPH treatment (150 MPa) at different number of passes (nP = 1–10). The conductivity and the particle size analyses, as well as the SEM images, clearly showed that PEF induces the permeabilization of the cell membranes in an intensity-dependent manner, without producing any cell debris, whereas HPH treatment causes the total disruption of the algae cells into small fragments. Coherently with the lower permeabilization capability, PEF promoted the selective extraction of carbohydrates (36%, w/w, of total carbohydrates), and low molecular weight proteins (5.2%, w/w, of total proteins). On the other hand, HPH induced the undifferentiated release of all the intracellular content, resulting in a 1.1 and 10.3 fold higher yields than PEF, respectively of carbohydrates and protein.These results suggest that, in a multi-stage biorefinery, PEF could represent a suitable cell disruption method for the selective recovery of small-sized cytoplasmic compounds, while HPH should be placed at the end the cascade of operations allowing the recovery of high molecular weight intracellular components.

Extraction of total nonstructural carbohydrates from forage plants containing starch by alpha -amylase.

Extraction of total nonstructural carbohydrates from forage plants containing starch by alpha -amylase.

Ultrasound-assisted extraction of fructans from agave (Agave tequilana Weber var. azul) at different ultrasound powers and solid-liquid ratios

The effects of ultrasound-assisted extraction (UAE) at different ultrasound power densities (UPDs; 40, 80, and 120 mW/mL) and solid:liquid (S:L) ratio (1:2, 1:3, and 1:6) on the extraction of carbohydrates from Agave tequilana plant of different ages were evaluated. Extracts obtained (6- and 7-year-old plant) were analyzed in the yield of carbohydrates (YC), fructan (FRU) content, simple sugars, fructan profile and the average degree of polymerization (DPn). UPD, S:L ratio, and plant age all affected YC, FRU, and DPn. Maximum YC and FRU were obtained from the older agave with UPD and S:L ratio of 120 mW/mL and 1:6, respectively; while glucose, fructose, and sucrose were highly released from the younger plant. Agave of 7-year-old presented the highest DPn. Fructan degradation occurred at high UPD, increasing the simple sugars and decreasing the DPn. Thermal-traditional extraction without sonication caused more fructan degradation; and overall, ultrasound enhanced fructan extraction and minimized fructan damage, representing a technological alternative for fructan extraction from agave.

Valorization of white wine grape pomace through application of subcritical water: Analysis of extraction, hydrolysis, and biological activity of the extracts obtained

White wine grape pomace (WWGP) was treated with subcritical water in a semi-continuous reactor, at 170, 190 and 210°C. Assays at 210°C led to highest recovery of carbohydrates (85% of total amount of carbohydrates of WWGP) and phenolic compounds (2.6g/100 gWWGP). Moreover, 48% of initial lignin was solubilized. The amount of carbohydrates recovered increased sharply in the initial stages of the process, due to the extraction of soluble carbohydrates, and then less pronouncedly, as hydrolysis of WWGP took place. The difference in the progress curves for the yields of carbohydrates and of phenolics allowed the separate recovery of carbohydrate-rich, and phenolics-enriched, GP extracts. The latter exhibited 10 times higher antioxidant activity (AA) than a GP extract obtained by hydro-alcoholic extraction, and 8 times lower AA than pure ascorbic acid. WWGP extracts were also found to have 4 times higher antimicrobial activity against Gram-positive than Gram-negative bacteria.

Water-Soluble Carbohydrate Extraction from Sweet Pearl Millet and Sweet Sorghum Biomass as Affected by Bagasse Impregnation

<abstract> <b><sc>Abstract.</sc></b> The extraction of the sugary juice from sweet sorghum and sweet pearl millet biomass is a major step for first-generation bioethanol production. However, an important amount of water-soluble carbohydrates (WSC) remains in the bagasse following a single pressing of the biomass in-field. Therefore, bagasse impregnation is required to collect residual carbohydrates. This study investigated the effects of bagasse impregnation liquid (water or juice from the first pressing of the biomass) and three impregnation durations (0, 30, or 60 min) for a second pressing on the WSC concentrations of the biomass, the bagasse, and the juice of sweet sorghum and sweet pearl millet. Our results showed that the impregnation duration had no effect on WSC concentration in the biomass, bagasse, and juice. However, water was more efficient than the first-pressing juice in extracting the residual WSC remaining in the biomass after the first pressing. The use of water for bagasse impregnation allowed extraction of a total of about 36% and 47.5% of WSC from sweet sorghum and sweet pearl millet biomass, respectively, compared to 28% and 41% when the first-pressing juice was used. Sweet sorghum and sweet pearl millet juice extracted from the biomass impregnated with water contained 21% and 28.5% more WSC, respectively, than the juice extracted from the biomass impregnated with the first-pressing juice. When pressing is carried out in-field, impregnation of the bagasse with water for a second pressing is highly recommended for more residual WSC extraction. However, the required quantity of water needs to be optimized.

Improvement in carbohydrate and phlorotannin extraction from Macrocystis pyrifera using carbohydrate active enzyme from marine Alternaria sp. as pretreatment

The commercial importance of brown seaweed has been increasing over the past decade, especially due to industries interested in the extraction of phycocolloids and, more recently, of polyphenol com ...

Microalgae Cultivation for Lipids and Carbohydrates Production

Microalgae are photoautotrophic microorganisms that can produce energy both by using sunlight, water and CO2 (phototrophic metabolism) and by using organic sources such as glucose (heterotrophic metabolism). Heterotrophic growth is a key factor in microalgae research, due to its increased productivity and the lower capital and operative costs compared to photoautotrophic growth in photobioreactors. Carbohydrate production from microalgae is usually investigated for the production of biofuels (e.g. bioethanol) by successive fermentation, but also other applications can be envisaged in biopolymers. In this work an increment in carbohydrate purity after lipid extraction was found. Protein hydrolysis for different microalgae strains (Scenedesmus sp. and Chlorella sp.) was investigated. Microalgae were cultivated under photoautotrophic or heterotrophic conditions, collecting biomass at the end of the growth. Biomass samples were dried or freeze dried and used for carbohydrate and lipid extraction tests. Lipid extraction was achieved using different organic solvents (methanol-chloroform and hexane-2propanol). Basic protein hydrolysis has been carried out testing different temperatures and NaOH concentrations values. Lipids were spectrophotometrically quantified, while residual biomass was saccharificated and the total amount of sugars was measured. Significant differences about the purity of extracted carbohydrates were found comparing dried with freeze dried biomass. However, not a very promising purification of carbohydrates was achieved after protein hydrolysis, asking for further analysis.

Protein and carbohydrate extraction from S. platensis biomass by ultrasound and mechanical agitation

Spirulina platensis is considered an alternative and excellent source of protein [46–63% dry basis (DB)], having protein levels comparable to meat and soybeans. Thus, it can be considered an adequate ingredient to supply the necessity of this compound in the food industry. Its carbohydrates (8–14% DB) may also be a useful food ingredient or a potential source of bioenergy. Thus, extracting these compounds from the microalgae biomass will maximize its exploitation. Sonication can completely or partially degrade the microalgal cell wall, providing a useful technique to extract the protein and carbohydrate. This study used a sequential strategy of experimental design (fractional factorial design and central composite rotatable design) to evaluate the protein and carbohydrate extraction from S. platensis defatted biomass using ultrasonic waves and mechanical agitation, under alkaline conditions. The optimal conditions for protein and carbohydrate co-extraction were established by selecting and maximizing the variables that significantly influenced the extraction. The optimized percentages recovery from the extraction process yielded 75.76% protein and 41.52% carbohydrate at 33–40min sonication and 40–55min agitation. The protein fraction may be further concentrated and purified for use in food formulations, and the carbohydrates may be a useful feedstock for bioethanol production.

The nutritional aspects of biorefined Saccharina latissima, Ascophyllum nodosum and Palmaria palmata

The chemical profile of biorefined Saccharina latissima, Ascophyllum nodosum and Palmaria palmata after carbohydrate and polyphenol extraction was analysed with the aim to evaluate the nutritional aspects of biorefined seaweeds as a novel animal feed supplement. Optimised enzymatic saccharification has been used to show that the protein concentration in the residue of P. palmata and A. nodosum can be increased by more than 2-fold. Nutritional value of the residue was further enhanced through an increase in total amino acids and fatty acids. As a consequence of removal of inorganic elements such as sodium, potassium and chloride, the total solid and ash content of all three seaweeds was reduced by around 40%. In contrast, divalent metals such as iron and zinc, as well as silicon, accumulated in all three residues. Potentially harmful components such as arsenic and iodine were reduced only in brown biorefined seaweeds, whilst in biorefined P. palmata, iodine increased by 39% compared to a 24% decline of arsenic. Nutritional values such as total fatty acid and total amino acid content increased in all three seaweeds after enzymatic saccharification. Polyphenol removal in all three seaweeds was >80% using aqueous acetonitrile and, in combination with enzymatic saccharification, did not impact on protein recovery in A. nodosum. This highlights the potential of biorefinery concepts to generate multiple products from seaweed such as extracts enriched in polyphenols and carbohydrates and residue with higher protein and lipid content.

Corn germ-bran oils extracted with alcoholic solvents: Extraction yield, oil composition and evaluation of protein solubility of defatted meal

Ethanol and isopropanol as solvents for vegetable oil extraction process have very attractive advantages including low toxicity, good operational security and high nutraceutical-extracting capability, useful in many vegetable substrates, besides they can be obtained from renewable sources. Therefore, the aim of this study was to evaluate the extraction of corn germ-bran oil with these alcohols and their aqueous solutions, at temperatures from 50 up to 80°C. The results showed that the oil and carbohydrate extraction yields are influenced by the type and hydration level of the solvent and temperature, while this last variable has not shown influence on liquid holdup. In sequential extraction trials, aqueous ethanol allowed oil extraction yields of approximately 70%, while the other solvents reached 90%. Regarding nitrogen solubility index of the protein present in defatted meal, a decrease was observed after the oil extraction process, being more prominent for systems where aqueous solvents were used. From the results, it can be inferred that alcoholic solvents enable extracting corn oils with a typical fatty acid composition; aqueous ethanol leads the extraction of higher levels of tocopherols and tocotrienols (449 and 195mg/kg, respectively) and absolute isopropanol has the best performance in the extraction of carotenoids (373mg/kg).

Enzyme-assisted extraction of carbohydrates from the brown alga Ecklonia radiata: Effect of enzyme type, pH and buffer on sugar yield and molecular weight profiles

The aim of this study was to understand the carbohydrate yield, composition, and molecular weight (MW) profiles of extracts from the brown alga Ecklonia radiata prepared using an enzyme-assisted extraction approach. The most significant effect on the total sugar yield was observed when comparing the use of salt-containing buffers (7.9–23.9g×100g−1 dry weight (DW)) to pH-adjusted water (23.6–27.9g×100g−1 DW), with the buffers significantly reducing the extraction efficiency in all instances. The inclusion of selected enzymes had little or no impact on total sugar yield, when compared with the corresponding solvent or buffer-only extractions. Marginal differences on total sugar yield were found when using different carbohydrate hydrolytic enzymes and proteases, and when changing pH in pH-adjusted water extractions. Both enzymes and pH influence sugar composition, and significantly affect MW profile of the polysaccharide fractions but in different ways. The acidic extraction at pH 4.5 yields lower MW components. Enzyme-assisted extraction reduced the MW of the extracted polysaccharides by 20–50% compared to pH-adjusted water only extractions.

Pretreatment of Sugar Beet Pulp with Dilute Sulfurous Acid is Effective for Multipurpose Usage of Carbohydrates.

Sulfurous acid was used for pretreatment of sugar beet pulp (SBP) in order to achieve high efficiency of both extraction of carbohydrates and subsequent enzymatic hydrolysis of the remaining solids. The main advantage of sulfurous acid usage as pretreatment agent is the possibility of its regeneration. Application of sulfurous acid as hydrolyzing agent in relatively low concentrations (0.6-1.0%) during a short period of time (10-20min) and low solid to liquid ratio (1:3, 1:6) allowed effective extraction of carbohydrates from SBP and provided positive effect on subsequent enzymatic hydrolysis. The highest obtained concentration of reducing substances (RS) in hydrolysates was 8.5%; up to 33.6% of all carbohydrates present in SBP could be extracted. The major obtained monosaccharides were arabinose and glucose (9.4 and 7.3g/l, respectively). Pretreatment of SBP with sulfurous acid increased 4.6 times the yield of glucose during subsequent enzymatic hydrolysis of remaining solids with cellulase cocktail, as compared to the untreated SBP. Total yield of glucose during SBP pretreatment and subsequent enzymatic hydrolysis amounted to 89.4% of the theoretical yield. The approach can be applied directly to the wet SBP. Hydrolysis of sugar beet pulp with sulfurous acid is recommended for obtaining of individual monosaccharides, as well as nutritional media.

Temperature effect on hydrothermal liquefaction of Nannochloropsis gaditana and Chlorella sp.

Temperature effect on hydrothermal liquefaction (HTL) of Nannochloropsis gaditana and Chlorella sp. was investigated with 10% biomass loading at HTL temperatures of 180–330°C, and reaction time of 30min. Maximum yields of 47.5% for Nannochloropsis sp. and 32.5% biocrude oil yields for Chlorella sp. were obtained at 300°C. The higher heating values of biocrude oils produced in this work ranged between 34 and 39MJ/kg. 79% of energy in the Nannochloropsis sp. was recovered at 300°C and 62% of energy recovery from Chlorella sp. was achieved at 200°C. Valuable nutrients (NH3–N and PO43−) produced during the HTL process were quantified from the aqueous phase for both strains of biomass. The aqueous phase samples obtained at all temperatures were also analyzed for amino acids and carbohydrates. The suitable temperatures for extraction of lipids, amino acids and carbohydrates have been identified. Sequential HTL experiments conducted have shown the prospect of recovering nutrients and other valuable byproducts along with biocrude oil. The experimental results and analysis indicate that sustainable biofuel production requires the development of strain based strategies for the hydrothermal liquefaction process.

Effect of pH during Extraction on the Antioxidant and Antiglycated Activities of Polysaccharides fromOpuntia Ficus Indica

The extraction of carbohydrates from Opuntia ficus indica cladodes at different pH was carried out by ultrasound followed by ethanol precipitation and dialysis. The extraction yields ranged from 4.6 to 24.5%. The highest content in galacturonic acid was observed for the acidic extract (37.4%). On high-performance size exclusion chromatography, the average molecular weight of all extracts ranged from 7,500,000 to 9,610,000 g/mol. The antioxidant activity of extracted polysaccharides was tested by three assays (1,1-diphenyl-2-picryl-hydrazil radical scavenging assay, Nitric oxide radical scavenging assay and Linoleic acid peroxidation). The glucose-induced advanced glycation end-product (AGE) formation of all extracts was also carried out using in vitro galactose–bovine serum albumin assay. Results showed that the acidic extract exhibited even better antioxidant capacity and inhibitory effect of AGE formation. Practical Applications Plant extracts containing polysaccharides are widely used in folk medicine for the treatment of skin and epithelium wounds and of mucous membrane irritation. In this case, polysaccharides extracted from Opuntia ficus indica cladodes, which is a plant native to South America and cultivated in dry regions as an important nutrient and food source, also are used in traditional medicine for their antiulcer and wound-healing effects. Thus, Opuntia ficus indica cladodes could be a natural candidate for research of herbal complement to the treatment of many diseases. The results found in this study reveal that the extraction under acidic conditions may enhance the antioxidant and antiglycated potential of polysaccharides extracted from Opuntia ficus indica cladodes.

Extraction of bioactive carbohydrates from artichoke (Cynara scolymus L.) external bracts using microwave assisted extraction and pressurized liquid extraction

Microwave assisted extraction (MAE) and pressurized liquid extraction (PLE) methods using water as solvent have been optimized by means of a Box–Behnken and 32 composite experimental designs, respectively, for the effective extraction of bioactive carbohydrates (inositols and inulin) from artichoke (Cynara scolymus L.) external bracts. MAE at 60°C for 3min of 0.3g of sample allowed the extraction of slightly higher concentrations of inositol than PLE at 75°C for 26.7min (11.6mg/g dry sample vs. 7.6mg/g dry sample). On the contrary, under these conditions, higher concentrations of inulin were extracted with the latter technique (185.4mg/g vs. 96.4mg/g dry sample), considering two successive extraction cycles for both techniques. Both methodologies can be considered appropriate for the simultaneous extraction of these bioactive carbohydrates from this particular industrial by-product. To the best of our knowledge this is the first time that these techniques are applied for this purpose.