Cellulose-rich Substrates Research Articles

Isolation, screening and characterization of efficient cellulose-degrading fungal and bacterial strains and preparation of their consortium under in vitro studies.

In this investigation, cellulose-degrading fungi and bacteria were isolated from different partially decomposed cellulose-rich substrates, such as groundnut residues, rice straw, and rotten wood, following dilution plating techniques on carboxymethyl cellulose agar media and screening for potential cellulose degradation ability. The development of a clear halo zone surrounding the microbial colonies during the initial screening process using the Congo red test (20 isolates) suggested cellulose hydrolysis, and the highest cellulase production activity was implied by the isolates with the largest clear zone ratio (9 isolates). Using both macroscopic and microscopic examinations, as well as standard biochemical tests outlined in Bergey's Manual of Determinative Bacteriology, the genus-level identification of fungi and bacteria was accomplished. In order to molecularly identify the 4 isolatedfungal and bacterial strains at the species level after being ultimately selected for cellulase production potential under in vitro studies, fungal and bacterial DNA was extracted and amplified by PCR using the universal primers ITS1 and ITS4 for fungi (ITS rRNA, 5.8S rRNA) and 8F and 1492R for bacterial isolates (16S rRNA). After sequencing, the PCR results were compared to other comparable sequences in GenBank (NCBI). Based on the available NCBI data, phylogenetic analysis of their ribosomal gene partial sequences revealed that DAJ2 (PP086700) shares 100% homology with Aspergillus foetidus, DTJ4 (PP086699) shares 99.74% similarity with Trichoderma atrobrunnium, DBJ6 (PP082584) shares 100% identity with Priestia megaterium, and DMB9 (PP082585) shares 99.88% homology with Micrococcus yunnanensis. The cellulolytic potential of Phanerochaete chrysosporium is well established. Therefore, it was considered a standard culture for comparison and was collected from the MTCC, Chandigarh, India. Overall, all 4 selected isolates and the check organism were mutually compatible or synergistic with each other, and their consortium is useful for the accelerated decomposition of organic constituents during rapid composting.

A tailored deep eutectic solvent for high-yield conversion of poplar residues to bio-based building blocks at mild conditions

The generation of condensed compounds in a deep eutectic solvent (DES) pretreatment has become a paramount factor that inhibits the further conversion of pretreated cellulose-rich substrate. This study proposed a novel three-constituent DES system for the value-added utilization of poplar residues by efficiently suppressing hemicellulose derived condensation reactions. The results showed that adding ethanol into the DES system could effectively deconstruct the recalcitrant structure of poplar residues, simultaneously hindering the condensed composition formation. Under optimum ethanol addition (30%), the maximum xylan and lignin removal of 87.94% and 90.99% could be achieved, with more than 90.47% of glucan being preserved. With this, the glucan enzymatic hydrolysis efficiency was remarkably improved to 100% under the pretreatment conditions of 100 °C for 60 min, which was 84.69 times higher than the regular DES-pretreated poplar residues (1.17%). The working mechanism of relieving condensation reactions was characterized by Py-GC–MS, NMR, SEM, FTIR, and others. The results demonstrated that the addition of ethanol could regulate the degradation/conversion pathway of hemicellulose and lignin precipitation, thus inhibit the formation of condensed compounds during the pretreatment.

Thermophilic biohydrogen production strategy using agro industrial wastes: Current update, challenges, and sustainable solutions

Continuously increasing wastes management issues and the high demand of fuels to fulfill the current societal requirements is not satisfactory. In addition, severe environmental pollution caused by generated wastes and the massive consumption of fossil fuels are the main causes of global warming. In this scenario, production of hydrogen from organic wastes is a potential and one of the most feasible alternatives to resolve these issues. However, sensitivity of H2 production at higher temperature and lack of potential substrates are the main issues which are strongly associated with such kinds of biofuels. Therefore, the present review is targeted towards the evaluation and enhancement of thermophilic biohydrogen production using organic, cellulosic wastes as promising bioresources. This review discusses about the current status, development in the area of thermophilic biohydrogen production wherein organic wastes as key substrate are being employed. The combinations of suitable organic and cellulose rich substrates, thermo-tolerant microbes, high enzymes stability may support to enhance the biohydrogen production, significantly. Further, various factors which may significantly contribute to enhance biohydrogen production have been discussed thoroughly in reference to the thermophilic biohydrogen production technology. Additionally, existing obstacles such as unfavorable thermophilic biohydrogen pathways, inefficiency of thermophilic microbiomes, genetic modifications, enzymes stability have been discussed in context to the possible limitations of thermophilic biohydrogen production strategy. Structural and functional microbiome analysis, fermentation pathway modifications via genetic engineering and the application of nanotechnology to enhance the thermophilic biohydrogen production have been discussed as the future prospective.

Effects of cow manure rate on average weight of fresh fruit, B.E (%) of Pleurotus citrinopileatus on rubber sawdust and waste substrate after growing Ganoderma lucidum

Currently in Vietnam, Pleurotus citrinopileatus is grown on cellulose-rich substrates. Pleurotus citrinopileatus was grown on a substrate of rubber sawdust and waste substrate after growing Ganoderma lucidum. The cultivation of Pleurotus citrinopileatus mushroom on the waste substrate after growing Ganoderma lucidum is to take advantage of agricultural waste and to create edible mushroom products for the market. These substrates were rich in cellulose and were supplemented with cow manure at different ratios of 0%, 2%, 4%, 6%, and 8% to obtain the average weight of fresh fruit bodies per plant embryo bag and biological efficiency B.E (%). This study is for surveying the effect of cow manure rate on the average weight of fresh fruit, B.E (%) of Pleurotus citrinopileatus on two substrates, including rubber sawdust and waste residue, after growing Ganoderma lucidum.

Effect of structural changes of lignin during the microwave-assisted alkaline/ethanol pretreatment on cotton stalk for an effective enzymatic hydrolysis

Effective delignification of lignocellulosic biomass is an important factor to improve the efficiency of enzymatic hydrolysis and ensure the economic feasibility of bio-refining. Cotton stalk (CS) was treated by a microwave-assisted alkaline/ethanol pretreatment (MAAP) (at 160 °C for 15 min) process to separate high-purity lignin and digestible cellulose-rich residue. Results showed that the MAAP process resulted in homogeneous lignin fractions with narrow polydispersity index (PI), and the isolated lignin fragments exhibited relatively smaller molecular weights and numerous phenolic OH groups than those in MWL. The crystallization index of cellulose-rich substrates was increased after the MAAP integrated process. Meanwhile, the glucose yield of the integrated residue reached the maximum (82.41%) after enzymatic hydrolysis. The utilization of MAAP process was a beneficial and promising scheme for the generation of lignin fractions with satisfactory purity and chemical reactivity, which will facilitate the value-added application of CS in the future biorefinery.

Acid tolerant multicomponent bacterial enzymes production enhancement under the influence of corn cob waste substrate

Cellulase enzymes have wide range of industrial application, but high production cost and relatively low efficiency are the main issues, which are needed to resolve. Substrate is known as the main contributor which can bring down the production cost of these enzymes at large scale. Therefore, in the present study, corn cob (Cc) waste has been employed as a potential substrate to produce efficient and good amount of cellulase using the bacterial strain Bacillus subtilis. Under the influence of optimal parameters while using the optimum concentration of Cc (7.0 g), maximum 12 IU/gds FP, 97 IU/gds BGL and 129 IU/gds EG have been recorded. Additionally, crude enzyme showed maximum FP activity of 14 IU/gds using 1.0 g/L peptone employed as the optimum organic nitrogen source. The bacterial cellulase exhibits temperature tolerance ability at 55 °C, and retains its half-life activity for 5 h and pH tolerance at pH 7.0 up to 55% of the relative activity. The results recorded in the present study may have potential for the large-scale and low-cost bacterial cellulase production using cellulose rich substrate e.g. Cc waste that can be vital for numerous industrial applications.

Physicochemical transformation and enzymatic hydrolysis promotion of reed straw after pretreatment with a new deep eutectic solvent

This work proposed a promising biorefinery method for the deconstruction of reed straw by using a novel deep eutectic solvent (DES) consisted of benzyltriethylammonium chloride/formic acid (BTEAC/FA). BTEAC/FA showed significant delignification and xylan removal while preserving most of the cellulose. Under the optimum conditions (molar ratio: 1:6), the glucose yield of cellulose-rich substrates by enzymatic hydrolysis reached 76.64%, which was about 5.24-fold higher than that of raw reed straw. The removal of lignin and hemicellulose and the changes in the cellulose crystal structure were presumed to the reason for enhancing enzymatic hydrolysis efficiency. The highest lignin yield reached 78.34%. Moreover, the lignin exhibited high purity (84.25%–91.45%), medium molecular weight (3812–9918 g/mol), and low polydispersity (1.47–2.75) because of the cleavage of β-O-4 and β-β linkages. Overall, this work provided a theoretical basis for the in-depth utilization of reed straw.

High yield of fermentable sugar from paper mulberry woods using phosphoric acid plus hydrogen peroxide pretreatment: Multifactorial investigation and optimization

Paper mulberry wood contains a high cellulose content of 59%, making it a potentially excellent feedstock for recovery of fermentable sugar used in bioethanol production. This potential was usefully exploited by establishing the optimal phosphoric acid plus hydrogen peroxide pretreatment of its woods using the response surface methodology. Pretreatment temperature, H3PO4 proportion in pretreatment mixture, and time significantly corelated with the removal of non-cellulosic polymers, cellulose recovery, enzymatic hydrolysis of the recovered cellulose, and glucose yield. At the optimized conditions of 34.7 ⁰C, 71.3% w/w H3PO4 proportion (the corresponding H2O2 proportion of 4.84% w/w), and 3.3 h, there were 97% biomass delignification, 100% hemicellulose removal, and high recovery of a cellulose-rich substrate characterized by decreased crystallinity, enhanced porosity, and complete glucose digestibility. The obtained high glucose yield of 493 mg/g raw wood was comparable to the best-reported yields from short-rotation woody energy crops.

Combined Sugarcane Pretreatment for the Generation of Ethanol and Value-Added Products

In this work, we have tested individual and combination of applications of ozonolysis and liquid hot water (LHW) to pretreat sugarcane bagasse (SCB) for the removal of enzyme and/or microbial inhibitors and generation of potential value-added chemicals. A solid content with 80% cellulose and a liquid phase (liquor) rich in phenolic derived compounds (3 g.L−1) from lignin, sugars (>20 g.L−1), and other compounds, such as furfural and hydroxymethylfurfural (HMF), were generated. Maximal (59%) glucan conversion occurred in the presence of double-pretreated bagasse, which had 32–50% more glucan available than the samples that were individually LHW or ozone-pretreated, resulting in maximal ethanol production (92% after 42 h) from double-pretreated SCB enzyme hydrolyzate. In summary, this work showed that ozone reacts effectively with lignin without the use of any other chemical reagent, and LHW pretreatment, followed by a washing step, was effective in solubilizing and cleaning up the fiber enzyme and microbial inhibitory compounds with ozone being effective against phenolics. Moreover, the generated cellulose-rich substrate is readily fermentable. The acidic liquor fraction removed by sequential washings and containing mainly sugars and phenolic compounds may be evaluated for use in green chemistry bioconversions processes.

The effect of alkaline extraction of hemicellulose on cocksfoot grass enzymatic hydrolysis recalcitrance

In order to verify the inhibitory influence of hemicellulosic structure and content on the enzymatic hydrolysis of cellulose from cocksfoot grass for bioethanol production, the fractional isolation and structural characterization of hemicelluloses and cellulose-rich substrates from the delignified cocksfoot grass was studied in detail. The results showed that the removal of hemicelluloses by alkaline treatments can greatly improve the enzymatic hydrolysis efficiency of cellulose in cocksfoot grass. As compared with the enzymatic hydrolysis yield (74.3%) and crystallinity index (30.5%) of the delignified cocksfoot grass (consisting mainly of cellulose and hemicelluloses), the enzymatic hydrolysis yields and crystallinity indexes of the four cellulose-rich substrates increased to 90.3–95.1% and 37.3–43.7%, respectively, due to the partial removal of hemicelluloses and some amounts of amorphous cellulose by alkaline treatments. Besides, the hemicellulosic fractions extracted with aqueous NaOH and KOH solutions from the delignified cocksfoot grass exhibited similar structures, which were composed of ʟ-arabino-(4-O-methyl-ᴅ-glucurono)xylans, galactoarabinoxylans, and β-glucans.

Enhancement of the production of chemicals and liquid fuels from grass biowaste via NaOH-Fenton pretreatment coupled with fast pyrolysis

Biomass waste pyrolysis has taken an increasing interest in producing biofuels and bio-based chemicals, but the complex compositions of pyrolytic liquid hinder its development and utilization. To address these challenges and improve the yield of target chemicals (levoglucosan) and aromatics, a novel two-stage process based on NaOH-Fenton pretreatment coupled with fast pyrolysis is firstly proposed. Firstly, rice straw was pretreated by dilute alkali to separate lignin fractions, and then the residue was further treated via Fenton reaction at room temperature to obtain cellulose-rich substrate. The fast pyrolysis of raw rice straw produced the complex compositions in the pyrolytic liquid. After NaOH-Fenton pretreatment, the target platform chemicals in the pyrolysate were effectively concentrated. The cellulose-rich substrate exhibited a very high absolute yield of levoglucosan (201.9 mg/g) as compared to raw rice straw (not detected). The lignin fractions recovered from this process were catalytically fast pyrolyzed for preparing aromatic fuels. Furtherly, the maximum removal rates of nitrogen (76.5%) and sulfur (93.3%) were achieved by the coupled process. A short-chain cellulose-rich substrate with similar dissociation energy of glycosidic bonds was formed by the NaOH-Fenton process based on the analytical results of the DFT calculation and mechanism. The similar dissociation energy of C–O bonds from the short-chain cellulose-rich substrate favors the formation of high-yield levoglucosan in subsequent fast pyrolysis. This work introduces a simple and highly efficient strategy to convert grass biowaste into value-added chemicals and liquid fuels.

The Carbon Source Controls the Secretion and Yield of Polysaccharide-Hydrolyzing Enzymes of Basidiomycetes.

In the present study, the polysaccharide-hydrolyzing secretomes of Irpex lacteus (Fr.) Fr. (1828) BCC104, Pycnoporus coccineus (Fr.) Bondartsev and Singer (1941) BCC310, and Schizophyllum commune Fr. (1815) BCC632 were analyzed in submerged fermentation conditions to elucidate the effect of chemically and structurally different carbon sources on the expression of cellulases and xylanase. Among polymeric substrates, crystalline cellulose appeared to be the best carbon source providing the highest endoglucanase, total cellulase, and xylanase activities. Mandarin pomace as a growth substrate for S. commune allowed to achieve comparatively high volumetric activities of all target enzymes while wheat straw induced a significant secretion of cellulase and xylanase activities of I. lacteus and P. coccineus. An additive effect on the secretion of cellulases and xylanases by the tested fungi was observed when crystalline cellulose was combined with mandarin pomace. In I. lacteus the cellulase and xylanase production is inducible in the presence of cellulose-rich substrates but is suppressed in the presence of an excess of easily metabolizable carbon source. These enzymes are expressed in a coordinated manner under all conditions studied. It was shown that the substitution of glucose in the inoculum medium with Avicel provides accelerated enzyme production by I. lacteus and higher cellulase and xylanase activities of the fungus. These results add new knowledge to the physiology of basidiomycetes to improve cellulase production.

A synergistic hydrothermal-deep eutectic solvent (DES) pretreatment for rapid fractionation and targeted valorization of hemicelluloses and cellulose from poplar wood

A synergistic pretreatment that realizing effective fractionation and targeted valorization can guarantee the implementability to future biorefinery scenario. In the present study, a stepwise approach using hydrothermal and deep eutectic solvents (DES) pretreatment was developed to preferentially dissociate hemicelluloses and further remove lignin from poplar, while retaining a cellulose-rich substrate that can be easily digested via enzymatic saccharification to obtain glucose. Results showed that the hydrothermal filtrate is mainly composed of xylooligosaccharide (XOS), monosaccharides, byproducts, and xylan-type hemicelluloses, which have homogenous structures and uniform molecular weights distribution as well as excellent antioxidant activity. Subsequent DES pretreatment further removed the lignin barriers, leading to a remarkable increase in the saccharification efficiency from 15.72% to 96.33% under optimum conditions for enzymatic hydrolysis. In short, the integrated pretreatment is effective for dissociating and chemical conversion of poplar wood, which was reasonable to promote the frontier of highly available biorefinery.

Tandem Character of Liquid Hot Water and Deep Eutectic Solvent to Enhance Lignocellulose Deconstruction.

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

Effect of integrated treatment on enhancing the enzymatic hydrolysis of cocksfoot grass and the structural characteristics of co-produced hemicelluloses

BackgroundCocksfoot grass (Dactylis glomerata L.) with high biomass yield and rich cellulose can be used to produce bioethanol as fuel additive. In view of this, ultrasonic and hydrothermal pretreatments followed by successive alkali extractions were assembled into an integrated biorefinery process applied on cocksfoot grass to improve its enzymatic hydrolysis. In this work, the effects of ultrasonic and hydrothermal pretreatments followed by sequential alkali extractions on the enzymatic hydrolysis of cocksfoot grass were investigated. In addition, since large amount of hemicelluloses were released during the hydrothermal pretreatment and alkali extraction process, the yields, structural characteristics and differentials of water- and alkali-soluble hemicellulosic fractions isolated from different treatments were also comparatively explored.ResultsThe integrated treatment significantly removed amorphous hemicelluloses and lignin, resulting in increased crystallinity of the treated residues. A maximum saccharification rate of 95.1% was obtained from the cellulose-rich substrate after the integrated treatment. In addition, the considerable hemicelluloses (31.4% water-soluble hemicelluloses and 53.4% alkali-soluble hemicelluloses) were isolated during the integrated treatment. The released water-soluble hemicellulosic fractions were found to be more branched as compared with the alkali-soluble hemicellulosic fractions and all hemicellulosic fractions were mixed polysaccharides mainly composed of branched xylans and β-glucans.ConclusionThe combination of ultrasonic and hydrothermal pretreatments followed by successive alkali extractions can dramatically increase the enzymatic saccharification rate of the substrates and produce considerable amounts of hemicelluloses. Detailed information about the enzymatic hydrolysis rates of the treated substrates and the structural characteristics of the co-produced hemicelluloses will help the synergistic utilization of cellulose and hemicellulose in cocksfoot grass.

Enzymatic response of ryegrass cellulose and hemicellulose valorization introduced by sequential alkaline extractions

BackgroundIn view of the natural resistance of hemicelluloses in lignocellulosic biomass on bioconversion of cellulose into fermentable sugars, alkali extraction is considered as an effective method for gradually fractionating hemicelluloses and increasing the bioconversion efficiency of cellulose. In the present study, sequential alkaline extractions were performed on the delignified ryegrass material to achieve high bioconversion efficiency of cellulose and comprehensively investigated the structural features of hemicellulosic fractions for further applications.ResultsSequential alkaline extractions removed hemicelluloses from cellulose-rich substrates and degraded part of amorphous cellulose, reducing yields of cellulose-rich substrates from 73.0 to 27.7% and increasing crystallinity indexes from 31.7 to 41.0%. Alkaline extraction enhanced bioconversion of cellulose by removal of hemicelluloses and swelling of cellulose, increasing of enzymatic hydrolysis from 72.3 to 95.3%. In addition, alkaline extraction gradually fractionated hemicelluloses into six fractions, containing arabinoxylans as the main polysaccharides and part of β-glucans. Simultaneously, increasing of alkaline concentration degraded hemicellulosic polysaccharides, which resulted in a decreasing their molecular weights from 67,510 to 50,720 g/mol.ConclusionsThe present study demonstrated that the sequential alkaline extraction conditions had significant effects on the enzymatic hydrolysis efficiency of cellulose and the investigation of the physicochemical properties of hemicellulose. Overall, the investigation the enzymatic hydrolysis efficiency of cellulose-rich substrates and the structural features of hemicelluloses from ryegrass will provide useful information for the efficient utilization of cellulose and hemicelluloses in biorefineries.

Facile and rapid fractionation of bamboo wood with a p-toluenesulfonic acid-based three-constituent deep eutectic solvent

Here, we report a strategy with the application of p-toluenesulfonic acid (p-TsOH) based three-constituent deep eutectic solvent (3c-DES) for the efficient fractionation of bamboo wood towards its main components. Three kinds of deep eutectic solvents (DESs), including choline chloride (ChCl)/ ethylene glycol (EG)/p-TsOH, tetrabutylammonium chloride (N4Cl)/EG/p-TsOH and tetrapropylammonium chloride (N3Cl) /EG/ p-TsOH, were facilely prepared and assessed for the pretreatment of bamboo wood. ChCl-EG-p-TsOH (molar ratio of 1:0.5:1) was found to be the most effective, evidenced by more than 93.36% xylan and 90.32% lignin removals with most of the cellulose (86.73%) retained in the pretreated bamboo in a short time of 10 min at 100 °C and a 10 wt. % solid loading, which significantly improved delignification by more than 85% compared with that of using ChCl-EG (molar ratio of 1:2) as a two-constituent at the same conditions. The 3c-DES pretreatment resulted in the desirable deconstruction of the recalcitrant of cell walls in woody biomass, evidenced by the higher glucose yield of 90.2% by the enzymatic hydrolysis of the cellulose-rich substrate, which was nearly four-fold higher than that of the untreated bamboo. The extracted lignin showed high purity (95%) with a moderate and homogeneous molecular weight, showing promising potential applications in the downstream production of biochemicals and biomaterials. Furthermore, the 3c-DES exhibited excellent recoverability by evaluating the fractionation efficiency and enzymatic hydrolysis performance with the recycled DES. The results from this study demonstrated that p-TsOH-based 3c-DES showed practical significance for the fast and effective fractionation of woody biomass for high-quality components.

Artificial vs natural Stachybotrys infestation-Comparison of mycotoxin production on various building materials.

The genus Stachybotrys belongs to filamentous fungi found in indoor environment, mostly on cellulose-rich substrates after water-damage. The major purpose of this study was to investigate the influence of different building materials in case of mold infestation on the mycotoxin production of Stachybotrys species. Fifteen Stachybotrys mycotoxins including satratoxins, phenylspirodrimanes, and recently discovered stachybotrychromenes were in the focus of the investigations. Artificial and natural infestations were compared to determine whether environmental factors, for example, time of growth, temperature, humidity, and material additives have an influence on the observed mycotoxin profiles. It turned out that mycotoxin profiles from Stachybotrys spp. on building materials can be influenced by cellulose, paints, and paste of the materials. The total toxin levels of artificially and naturally contaminated gypsum board samples ranged up to 30µg/cm2 , whereas wallpaper samples showed total toxin levels in the range of 20-66µg/cm2 . A naturally infested sample disclosed the conversion of the dialdehyde components to the corresponding lactone isomers under the influence of light.

Synergistic benefits from a lignin-first biorefinery of poplar via coupling acesulfamate ionic liquid followed by mild alkaline extraction

A novel mind-set, termed lignin-first biorefinery, is bewitching to synchronously boost lignin output for entirely lignocellulosic utilization. A lignin-first fractionation, using a food-additive derived ionic liquid (1-ethyl-3-methylimidazolium acesulfamate, emimAce) and mild alkaline pretreatments, was formed for the purposely isolating poplar lignin, whilst delivering a cellulose-rich substrate that can be easily available for enzymatic digestion. The emimAce-driven lignin, alkali-soluble lignin and hemicellulose, and accessible cellulose were sequentially gained. We introduce a lignin-first approach to extract the amorphous fractions, destroy the robust architecture, and reform cellulose-I to II, thereby advancing the cellulose bioconversion from 15.4 to 90.5%. A harvest of 70.7% lignin, 52.1% hemicellulose, and 330.1 mg/g glucose was fulfilled from raw poplar. A structural ‘‘beginning-to-end’’ analysis of lignin inferred that emimAce ions are expected to interact with lignin β-aryl-ether due to their aromatic character. It was reasonable to derive benefits from lignin-first technique that can substantially augment the domain of biorefinering.

Influence of temperature and soda concentration in a thermo-mechano-chemical pretreatment for bioethanol production from sweet corn co-products

A continuous process combining an alkaline pretreatment, neutralization and injection of enzymes within a twin screw extruder was previously implemented and demonstrate industrial potential. The present work focuses on the investigation of the effects of alkali and temperature during the alkaline pretreatment of sweet corn co-products (SCC) for the production of fermentable sugars with a lower chemical input. Study of NaOH/SCC and internal temperature was performed in ranges of 4–8% (w/w) and 50–170 °C in a laboratory scale twin screw extruder. Analysis of carbohydrates and lignin of the pretreated biomass was performed and the filtration efficiency was also monitored through extrudate dry matter and filtrate mineral matter. The carbohydrate accessibility and process performances were studied by the enzymatic hydrolysis of the extrudate. Increasing temperature reinforces the effects of soda on solubilization of hemicelluloses, thus a hemicelluloses removal reach more than 50%. At optimal conditions, the cellulose-rich substrate after enzymatic hydrolysis achieve a glucose released of 70%, with glucose and xylose yields of 250 g per 1Kg of dry SCC.