Valorization of cashew apple bagasse using acetic acid pretreatment: Production of cellulosic ethanol and lignin for their use as sunscreen ingredients

The present study focuses on the fractionation of cashew apple bagasse via a pretreatment using acetic acid as a delignifying agent and sulfuric acid as an external catalyst. As expected, the concentrations of both acids and the incubation time dramatically affected delignification and hemicellulose solubilization. Under the optimal pretreatment conditions, recycling of the spent liquor had no apparent impact on the chemical composition of the pretreated material, yield of sugar produced via enzymatic hydrolysis (∼37 g/L reducing sugars at 7.5% (w/v) solid loading), or yield of ethanol obtained via fermentation with Saccharomyces cerevisiae (∼16 g/L at 10% (w/v) solid loading). The lignin recovered from the spent liquor showed a good ultraviolet protective effect; the addition of 5% (w/w) of the biopolymer increased the sun protection factor of a commercial sunscreen lotion from 21.62 to 40.71. The combined use of hydrogen peroxide and ultraviolet radiation reduced the organosolv lignin color (absorbance at 450 nm was four times lower) owing to aromatic ring cleavage, but cosmetics containing whitened organosolv lignin had low sun protection factor values. In summary, the results obtained in this study demonstrate the utility of organic acid pretreatment in the valorization of lignocellulosic materials.     

Fractionation of Eucalyptus grandis chips by dilute acid-catalysed steam explosion

Steam explosion of Eucalyptus grandis has been carried out under various pretreatment conditions (200-210 degrees C, 2-5 min) after impregnation of the wood chips with 0.087 and 0.175% (w/w) H2SO4. This study, arranged as a 2(3) factorial design, indicated that pretreatment temperature is the most critical variable affecting the yield of steam-treated fractions. Pretreatment of 0.175% (w/w) H2SO4-impregnated chips at 210 degrees C for 2 min was the best condition for hemicellulose recovery (mostly as xylose) in the water soluble fraction, reaching almost 70% of the corresponding xylose theoretical yield. By contrast, lower pretreatment temperatures of 200 degrees C were enough to yield steam-treated substrates from which a 90% cellulose conversion was obtained in 48 h, using low enzyme loadings of a Celluclast 1.5 1 plus Novozym 188 mixture (Novo Nordisk). Release of water-soluble chromophores was monitored by UV spectroscopy and their concentration increased with pretreatment severity. The yield of alkali-soluble lignin increased at higher levels of acid impregnation and pretreatment temperatures. Thermoanalysis of these lignin fractions indicated a pattern of lignin fragmentation towards greater pretreatment severities but lignin condensation prevailed at the most drastic pretreatment conditions.     

Effects of lignin content on the properties of lignocellulose-based biocomposites

The paper is focused on the analysis of the behaviour of biocomposites (biodegradable composites) which are reinforced with different fillers fractions, with varying lignin contents. These materials have been carried-out by extrusion and injection moulding. The matrix, an aromatic copolyester (polybutylene adipate-co-terephthalate), is biodegradable. The lignocellulose fillers are a by-product of an industrial fractionation process of wheat straw. From the raw agro-material and by lignin extractions, various fillers fractions have been obtained by varying the fractionation conditions, both on the liquid media (aqueous or organic) and on the temperature. The fillers lignin contents vary from 30 to 14 wt% with a resultant increase of the cellulose content. We have analysed the impact of the different extraction conditions on the fillers surface and size distribution, and also on the final thermal and mechanical properties of the biocomposites. These materials present significant differences of behaviour which can fulfil some requirements for applications, such as non-food packaging or other short-lived applications (agriculture, sport …) where long-lasting polymers are not entirely adequate.     

Preparative fractionation of lignin by gel-permeation chromatography

The combination of an agarose gel (Bio-Gel A) and a dioxane–water (1:1) solvent system allowed the fractionation, on a preparative scale, of a very polydisperse, non-derivatized lignin preparation (enzymatically liberated lignin prepared from sweetgum sapwood with Lenzites trabea). Three fractions differing markedly in molecular weight were obtained. A gel of crosslinked alkylated dextran (Sephadex LH-20) with the same solvent system allowed division of the lowest molecular weight fraction into two fractions. These materials were characterized by measurements of intrinsic viscosity and number-average molecular weights in dimethylformamide and dioxane–water. It was established that the two highest molecular weight fractions were associated in an average trimeric form in dioxane-water (1:1) as compared to the form (considered to be molecular) that occurred in dimethylformamide. Molecular size distributions and eluant volumes of the fractions were determined with a Sephadex G-100–formamide system, the latter being one of the most powerful nonaqueous solvents for lignin. Adsorption effects were known to be absent in this case, and the lignin molecules were considered to be unassociated in formamide. The four fractions were distinguishable with the formamide–G-100 system, thus indicating that the original fractionation was based on molecular size. The enzymatically liberated lignin contained molecules that comprised a continuum of molecular weights from approximately monomeric to molecules that were at the limit of the solvating power of dioxane–water (1:1) and dimethylformamide. Limited physicochemical data were consistent with a compact, approximately spherically symmetric shape of the lignin in solution.     

The Influence of Hemicellulose and Lignin Removal on the Enzymatic Digestibility from Sugarcane Bagasse

Sugarcane bagasse (SCB) was pretreated with liquid hot water (LHW) and aqueous ammonia (AA), with the objective of investigating the influence of hemicellulose and lignin removal on the enzymatic digestibility and sugar recovery. The experimental results show that LHW and aqueous ammonia have a good performance in terms of hemicellulose dissolution and lignin removal respectively. The biggest xylan recovery of 74.3 % was obtained for LHW pretreatment at 160 °C, 5 %?w/v for 20 min with the xylan dissolution of 83.1 %. And the biggest lignin removal of 84.0 % was obtained for aqueous ammonia pretreatment at 160 °C, 10 %?w/v for 60 min. Moreover, the aperture and surface area of the sample were enlarged by the liquid hot water, which improves the accessibility of the substrate to the enzyme. The lignin removal caused by aqueous ammonia pretreatment can reduce the absorption of enzyme. In addition, the correlation between the compositional change and the enzymatic digestibility indicates that the removal of hemicellulose was more effective than lignin for destruction of the hemicellulose–lignin–cellulose structure.     

Comparison of different pretreatment methods for lignocellulosic materials. Part I: conversion of rye straw to valuable products

The conversion of lignocellulose to valuable products requires I: a fractionation of the major components hemicellulose, cellulose, and lignin, II: an efficient method to process these components to higher valued products. The present work compares liquid hot water (LHW) pretreatment to the soda pulping process and to the ethanol organosolv pretreatment using rye straw as a single lignocellulosic material. The organosolv pretreated rye straw was shown to require the lowest enzyme loading in order to achieve a complete saccharification of cellulose to glucose. At biomass loadings of up to 15% (w/w) cellulose conversion of LHW and organosolv pretreated lignocellulose was found to be almost equal. The soda pulping process shows lower carbohydrate and lignin recoveries compared to the other two processes. In combination with a detailed analysis of the different lignins obtained from the three pretreatment methods, this work gives an overview of the potential products from different pretreatment processes.     

Unpolluted fractionation of wheat straw by steam explosion and ethanol extraction

An unpolluted process of wheat straw fractionation by steam explosion coupled with ethanol extraction was studied. The wheat straw was steam exploded for 4.5 min with moisture of 34.01%, a pressure of 1.5 MPa without acid or alkali. Hemicellulose sugars were recovered by water countercurrent extraction and decolored with chelating ion exchange resin D412. The gas chromatography (GC) and high-performance liquid chromatography (HPLC) analysis results indicated that there were organic acids in the hemicellulose sugars and the ratio of monosaccharides to oligosaccharides was 1:9 and the main component, xylose, was 85.9% in content. The total recovery rate of hemicellulose was 80%. Water washed materials were subsequently extracted with ethanol. The optimum extraction conditions in this work were 40% ethanol, fiber/liquor ratio 1:50 (w/v), severity log(R)=3.657 (180 degrees C for 20 min), 0.1% NaOH. The lignin yield was 75% by acid precipitation and 85% ethanol solvent was recovered. The lignin was purified using Bj?rkman method. Infrared spectrometry (IR) results indicated that the lignin belonged to GSH (guaiacyl (G) syringyl (S) and p-hydroxyphenyl (H)) lignin and its purity rate reached 85.3%. The cellulose recovery rate was 94% and the results of electron spectroscopy for chemical analysis (ESCA) and infrared spectrometry (IR) showed that hemicellulose and lignin content decreased after steam explosion and ethanol extraction.     

Effect of Nutrition and Physical Factors on Mycelial Growth and Production of Pigments and Nonchromatic UV-absorbing Compounds of Alternaria eichhorniae

Alternaria eichhorniae is a host-specific biocontrol agent for managing waterhyacinth ( Eichhornia crassipes ) in Egypt. An important diagnostic characteristic of this fungus is the production of crimson-red phytotoxic pigments in the medium under certain conditions. A virulent isolate, A. eichhorniae 5 (Ae5), was studied to determine the optimum conditions for its growth and production of pigments and nonchromatic UV-absorbing metabolites (UVACs). The maximum production of pigments was obtained when cultures were grown on potato dextrose agar (PDA) with 20% dextrose, an initial pH of 4.5 at 25–30°C under continuous darkness or diurnal light, and without wrapping the culture plates. The maximum yields of the nonchromatic, 229- and 286-nm-absorbing compounds were obtained on PDA with 20–50% of dextrose at 20–30°C under continuous darkness. Culture plates, unwrapped or wrapped with only one layer of Parafilm at pH from 3.8 to 6.2 were favourable in this respect. There was a strong inverse relationship between linear mycelial growth and pigmentation as a function of light. Furthermore, the reduction in aeration, presumably proportional to the number of layers of Parafilm wrappings, led to lower levels of the red pigment(s) and the nonpigmented UVACs, to reduced mycelial growth, and a suppression of sporulation. Different culture-filtrate fractions of Ae5 were tested for phytotoxicity. At the concentrations of 0.5 and 1% w/v of the partially purified culture filtrate fractions, all except the butanol 1 fraction, had no toxic effect on waterhyacinth leaf-segments. Butanol fractions at 10% (w/v) concentration were significantly more damaging than aqueous fractions (10% w/v) and the area of necrosis increased with time.     

Study of the antioxidant capacity of Miscanthus sinensis lignins

The present work studied the antioxidant capacity of the lignin obtained from Miscanthus sinensis. As the lignin structure is very complex, extraction and separation processes highly influence obtained lignin structure and its properties, including the antioxidant activity. Lignin fractions were obtained from black liquor resulting from different fractionating and autohydrolysis processes of M. sinensis. Different lignin fractions with specific molecular weight were separated by ultrafiltration using different cut-off ceramic membranes (10 and 15 kDa). The physico-chemical properties, phenolic groups content and the antioxidant capacity of each lignin sample were studied. It was found that antiradical activity of the analyzed lignin samples was closely related with the used fractionating process (soda, organosolv and autohydrolysis treatments). The ultrafiltration process allows obtaining lignins with different antioxidant capacity, improving this property as the used cut-off was greater.     

Lignocellulosic biomass fractionation: I - solvent extraction in a novel reactor

Capium (elephant grass) chips were treated at 180°C for 1 to 3 h, solid concentrations 3 to 14%, with 50% aquous ethanol in a recently-developed reactor. About 70% delignification and 90% hemicellulose removal in solid form, and 95% glucose yield in 16h by enzymatic hydrolysis, were obtained under optimum reaction conditions. The effectiveness of lignocellulosic biomass fractionation is due largely to the reactor design which facilitates efficient separation of components and overcomes lignin condensation problems.     

Chromatographic detection of lignin-carbohydrate complexes in annual plants by derivatization in ionic liquid

The opportunity for detecting the presence and the amount of lignin-carbohydrate complexes (LCCs) in renewable feedstocks is a major issue for the complete utilization of biomass. Indeed, LCCs are known to shield cellulose from enzymatic hydrolysis, reducing the efficiency of the digestion processes needed for the production of biobased products. This study is focused on the chromatographic characterization of lignocellulose from agricultural residues (rice husk, wheat straw) and herbaceous energy crops ( Arundo donax , Miscanthus sinesis ) and their fractionation products (hemicellulose, cellulose, and lignin). Exploiting alternative chemical derivatizations on the aforementioned samples, it was possible to discern the connectivity among the various lignocellulosic components. The complete acetylation and benzoylation of the milled native substrates in ionic liquid media, and the systematic comparison between their GPC-UV chromatograms collected at different wavelengths has revealed itself as a straightforward technique in the detection of LCCs. This novel approach proved an extensive connectivity between the lignin and the hemicellulosic for all the analyzed specimens, whereas the cellulosic fraction was conceived as a substantially unbound moiety, accounting for the sample composition at higher molecular weights. Moreover, the collected lignin fractions were extensively characterized by means of (31)P NMR and 2D-HSQC techniques.     

从老抽酱醪中分离耐盐性酵母的研究

以老抽酱醪为实验材料进行耐盐性酵母菌种分离,并做菌种鉴定。分析了在不同盐度条件下耐盐性酵母菌的生长情况和生长过程中培养基总糖的消耗,可以发现实验得到的酵母在22％（质量与体积}E）盐度下依然能够良好生长。结果表明,实验分离出的No．2菌在同级盐度的条件下的生长量要明显高于No．1菌,但在乙醇产率方面,两株菌在相同的含盐量为16％（质量与体积比）的麦芽汁培养基中发酵8d,No．1菌的乙醇产率为3．1％（体积比）,No．2菌的乙醇产率2．9％（体积比）。     

An integrated spectroscopic and wet chemical approach to investigate grass litter decomposition chemistry

The chemical transformations that occur during litter decomposition are key processes for soil organic matter formation and terrestrial biogeochemistry; yet we still lack complete understanding of these chemical processes. Thus, we monitored the chemical composition of Andropogon gerardii (big bluestem grass) litter residue over a 36 month decomposition experiment in a prairie ecosystem using: traditional wet chemical fractionation based upon digestibility, solid state ¹³C nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The goals of this study were to (1) determine the chemical changes occurring during A. gerardii litter decomposition, and (2) compare the information obtained from each method to assess agreement. Overall, we observed a 97 % mass loss of the original litter, through a two-stage decomposition process. In the first stage, within 12 months, non-structural, cellulose and hemicellulose fractions not encrusted in lignin were preferentially and rapidly lost, while the acid unhydrolyzable residue (AUR) and microbial components increased. During the second stage, 12–36 months, all wet chemical fraction masses decreased equivalently and slowly with time, and the AUR and the lignin-encrusted cellulose fractions decomposition rates were comparable to each other. Method comparisons revealed that wet chemical fractionation did not accurately follow the initial litter structures, particularly lignin, likely because of chemical transformations and accumulation of microbial biomass. FTIR and NMR were able to determine bulk structural characteristics, and aid in elucidating chemical transformations but lacked the ability to measure absolute quantities of structural groups. As a result, we warn from the sole use of wet chemical methods, and strongly encourage coupling them with spectroscopic methods. Our results overall support the traditional chemical model of selective preservation of lignin, but shows that this is limited to the early stages of decomposition, while lignin is not selectively preserved at subsequent stages. Our study also provides important evidence regarding the impact of chemically different litter structures on decomposition rates and pathways.     

Molecular state of cy tochrome c oxidase on polyacrylamide gel electrophoresis

The molecular state of cytochrome oxidase, complex IV (EC 1.9.3.1), was studied by polyacrylamide gel electrophoresis. Cytochrome oxidase in the presence of non-ionic detergent Emasol 1130 ran as a single band under conditions where there is a small sieving effect as in a 2.5% polyacrylamide gel. This polymeric form is an association of different molecular species that can be dissociated on a preparative electrophoresis system. In such a system, five species of different molecular size with enzymic activity are obtained, though the specific activity is lower in the first running fractions. After treatment in highly dissociating conditions (phenol-acetic acid-water (2:1:1, w/v/v) the polymeric form and the different species present two main fractions on analytical polyacrylamide electrophoresis (7.5% in acrylamide, 35% acetic acid, and 5 m urea). The original form after treatment with 2.5% sodium dodecylsulfate (SDS) also presents two fractions on analytical electrophoresis in the presence of 2.5% sodium dodecylsulfate. These results suggest that the basic subunit structure of the various forms of the cytochrome oxidase consists of two closely related polypeptides. The highest activity was found with the polymeric form of cytochrome oxidase, a fact which may have physiological significance in relation to the natural state of this enzyme in the mitochondrion.     

Fractionation of Forest Residues of Douglas-fir for Fermentable Sugar Production by SPORL Pretreatment

Douglas-fir (Pseudotsuga menziesii) forest residues were physically fractionated through sieving. The bark and wood were separated for large-sized fractions (>12.7?mm), and their contents were determined. The chemical compositions of the large fractions were calculated based on the contents and chemical compositions of the bark and wood. The chemical compositions of the fine fractions were analyzed. The bark and wood content in the fine fractions was calculated based on the measured glucan and lignin contents in each fraction. It was found that fractionation by particle/chip size can effectively fractionate bark and wood and therefore lignin from carbohydrates. The large-sized fractions (>12.7?mm) represent approximately 60?% of the collected forest residues but only contain approximately 37?% of the total bark and 35?% of the total ash, or a selectivity over bark and ash of 1.6 and 1.7, respectively. Pretreatment of forest residues by sulfite pretreatment to overcome recalcitrance of lignocelluloses and subsequent enzymatic hydrolysis revealed the presence of 14.3?% bark can reduce substrate enzymatic digestibilities (SED) 16?% compared with that from a bark-free sample. The SED of a bark is 41?% compared with 73?% for wood when pretreated under the same conditions. Separating pretreatment of bark from wood is beneficial for producing a more enzymatically digestible substrate. The results from the present study could have significant implications for harvesting forest residues.     

Fractionation of wheat straw by atmospheric acetic acid process

Fractionation of wheat straw was investigated using an atmospheric acetic acid process. Under the typical conditions of 90% (v/v) aqueous AcOH, 4% H(2)SO(4) (w/w, on straw), ratio of liquor to straw (L/S) 10 (v/w), pulping temperature 105 degrees C, and pulping time 3h, wheat straw was fractionated to pulp (cellulose), lignin and monosaccharides mainly from hemicellulose with yields of approximately 50%, 15% and 35%, respectively. Acetic acid pulp from the straw had an acceptable strength for paper and could be bleached to a high brightness over 85% with a short bleaching sequence. Acetic acid pulp was also a potential feedstock for fuels and chemicals. The acetic acid process separated pentose and hexose in wheat straw to a large extent. Most of the pentose (xylan) was dissolved, whereas the hexose (glucan) remained in the pulp. Approximately 30% of carbohydrates in wheat straw were hydrolyzed to monosaccharides during acetic acid pulping, of which xylose accounted for 70% and glucose for 12%. The acetic acid lignin from wheat straw showed relatively lower molecular weight and fusibility, which made the lignin a promising raw material for many products, such as adhesive and molded products.     

Fractionation and characterization of chlorophyll and lignin from de-juiced Italian ryegrass (Lolium multifolrum) and timothy grass (Phleum pratense)

In this study, de-juiced Italian ryegrass and timothy grass were successfully fractionated into one chlorophyll rich fraction, two lignin fractions, two hemicellulosic preparations, and one cellulosic fraction by sequential processes with 80% ethanol containing 0.2% NaOH, 2.5% H₂O₂–0.2% EDTA containing 1.5% NaOH, and 2.5% H₂O₂–0.2% TAED containing 1.0% NaOH at 75 °C for 3 h, respectively. The yields of chlorophyll rich fraction and total lignin fraction were found to be 6.1 and 11.0% from de-juiced Italian ryegrass, and 12.7 and 13.2% from de-juiced timothy grass. It should be noted that the two chlorophyll rich fractions contained noticeable amounts of contaminated hemicelluloses (17.1–18.8%) and lignin, whereas the four lignin fractions contained only small amounts of bound hemicelluloses (5.6–8.6%). Nitrobenzene oxidation and NMR spectra of the lignin fraction revealed that the presence of both guaiacyl and syringyl units, as well as p-hydroxyphenyl structures. Small amounts of esterified p-coumaric acids and mainly etherified ferulic acids were also identified in the lignin fractions. It was found that the lignin fractions obtained from the two different grasses had very similar structural composition. They are distinguished by rather low amounts of β-O-4 structures, resinol units (β-β), and of condensed units (β-5 and 5-5). This trait is even more pronounced in the production of phenolic compounds for chemical industry from grass.     

Fractionation analysis of the endosomal compartment during rat reticulocyte maturation

A subcellular fractionation procedure was developed to isolate the different endosomal compartments present during reticulocyte maturation. After reticulocyte lysis and removal of excess haemoglobin by gel chromatography, membrane vesicles were separated over a discontinuous sucrose gradient (10-40%). Two fractions were isolated: P1 at the 25-35% sucrose interface and P2 at the 17-25% sucrose interface. These fractions were morphologically characterized by electron microscopy and the distribution of endocytic markers in the fractions was detected by Western blot. Moreover, this fractionation technique was used to study the effect of 3-methyladenine (3-MA), an autophagy inhibitor, on reticulocyte maturation. The presence of 3-MA during in vitro maturation of reticulocytes induced a decrease in exosome secretion, as measured by the amount of transferrin receptor (TfR) released in the extracellular medium. The subcellular fractionation results suggested that multivesicular endosome formation from early endosomes is the step affected by 3-MA.     

Universal fractionation of lignin–carbohydrate complexes (LCCs) from lignocellulosic biomass: an example using spruce wood

It is of both theoretical and practical importance to develop a universally applicable approach for the fractionation and sensitive lignin characterization of lignin–carbohydrate complexes (LCCs) from all types of lignocellulosic biomass, both natively and after various types of processing. In the present study, a previously reported fractionation approach that is applicable for eucalyptus (hardwood) and flax (non‐wood) was further improved by introducing an additional step of barium hydroxide precipitation to isolate the mannan‐enriched LCC (glucomannan‐lignin, GML), in order to suit softwood species as well. Spruce wood was used as the softwood sample. As indicated by the recovery yield and composition analysis, all of the lignin was recovered in three LCC fractions: a glucan‐enriched fraction (glucan‐lignin, GL), a mannan‐enriched fraction (GML) and a xylan‐enriched fraction (xylan‐lignin, XL). All of the LCCs had high molecular masses and were insoluble or barely soluble in a dioxane/water solution. Carbohydrate and lignin signals were observed in ¹H NMR, ¹³C CP‐MAS NMR and normal‐ or high‐sensitivity 2D HSQC NMR analyses. The carbohydrate and lignin constituents in each LCC fraction are therefore believed to be chemically bonded rather than physically mixed with one another. The three LCC fractions were found to be distinctly different from each other in terms of their lignin structures, as revealed by highly sensitive analyses by thioacidolysis‐GC, thioacidolysis‐SEC and pyrolysis‐GC.     

BIOETHANOL PRODUCTION FROM LEAFY BIOMASS OF MANGO (Mangifera indica) INVOLVING NATURALLY ISOLATED AND RECOMBINANT ENZYMES

The present study describes the usage of dried leafy biomass of mango (Mangifera indica) containing 26.3% (w/w) cellulose, 54.4% (w/w) hemicellulose, and 16.9% (w/w) lignin, as a substrate for bioethanol production from Zymomonas mobilis and Candida shehatae. The substrate was subjected to two different pretreatment strategies, namely, wet oxidation and an organosolv process. An ethanol concentration (1.21 g/L) was obtained with Z. mobilis in a shake-flask simultaneous saccharification and fermentation (SSF) trial using 1% (w/v) wet oxidation pretreated mango leaves along with mixed enzymatic consortium of Bacillus subtilis cellulase and recombinant hemicellulase (GH43), whereas C. shehatae gave a slightly higher (8%) ethanol titer of 1.31 g/L. Employing 1% (w/v) organosolv pretreated mango leaves and using Z. mobilis and C. shehatae separately in the SSF, the ethanol titers of 1.33 g/L and 1.52 g/L, respectively, were obtained. The SSF experiments performed with 5% (w/v) organosolv-pretreated substrate along with C. shehatae as fermentative organism gave a significantly enhanced ethanol titer value of 8.11 g/L using the shake flask and 12.33 g/L at the bioreactor level. From the bioreactor, 94.4% (v/v) ethanol was recovered by rotary evaporator with 21% purification efficiency.