Reduction In Cellulose Crystallinity Research Articles

Metabolomics-based study of chemical compositions in cellulase additives derived from a tobacco-origin Bacillus subtilis and their impact on tobacco sensory attributes.

To enhance the quality of tobacco leaves and optimize the smoking experience, diverse strains of functional bacteria and their associated metabolites have been used in tobacco aging. Exogenous cellulase additives are frequently employed to facilitate the degradation of cellulose and other macromolecular matrices and enhance the quality of the tobacco product. However, little is known about how microbial metabolites present in exogenous enzyme additives affect tobacco quality. In this study, crude cellulase solutions, produced by a tobacco-originating bacterium Bacillus subtilis FX-1 were employed on flue-cured tobacco. The incorporation of cellulase solutions resulted in the reduction of cellulose crystallinity in tobacco and the enhancement of the overall sensory quality of tobacco. Notably, tobacco treated with cellulase obtained from laboratory flask fermentation demonstrated superior scent and flavor attributes in comparison to tobacco treated with enzymes derived from industrial bioreactor fermentation. The targeted and untargeted metabolomic analysis revealed the presence of diverse flavor-related precursors and components in the cellulase additives, encompassing sugars, alcohols, amino acids, organic acids, and others. The majority of these metabolites exhibited significantly higher levels in the flask group compared to the bioreactor group, probably contributing to a pronounced enhancement in the sensory quality of tobacco. Our findings suggest that the utilization of metabolic products derived from B. subtilis FX-1 as additives in flue-cured tobacco holds promise as a viable approach for enhancing sensory attributes, establishing a solid theoretical foundation for the potential development of innovative tobacco aging additives.

Brown sugar as a carbon source can make agricultural organic waste compost enter the secondary thermophilic stage and promote compost decomposition.

To enhance the efficiency of composting agricultural organic waste (AOW), this study aimed to examine the impact of inoculating tomato straw compost with two distinct microbial agents: ZymoZone (ZZ), a composite microbial agent derived from the straw compost and Effective Microorganisms (EM), a commercial microbial agent. Furthermore, in order to reactivate the microorganisms within the compost during the initial high temperature phase, 10% brown sugar was introduced as a carbon source. The objective of this addition was to assess its influence on the composting process. The findings revealed that compared to the control (CK) group, the ZZ and EM treatments extended the first high-temperature phase by 2 and 1day, respectively. Furthermore, with the addition of 10% brown sugar, the ZZ and EM treatments remained in the second high-temperature phase for 8 and 7days, respectively, while the CK treatment had already entered the cooling stage by then. Notably, the inoculation of microbial agents and the addition of brown sugar substantially augmented the activity of lignocellulose-related hydrolases, thereby promoting the degradation of lignocellulose in the ZZ and EM treatment groups. This was confirmed by FTIR analysis, which demonstrated that the addition of microbial agents facilitated the degradation of specific substances, leading to reduced absorbance in the corresponding spectra. XRD analysis further indicated a notable reduction in cellulose crystallinity for both the ZZ (8.00%) and EM (7.73%) treatments. Hence, the incorporation of microbial agents and brown sugar in tomato straw compost effectively enhances the composting process and improves the quality of compost products.

Twin-Screw Extrusion Mechanical Pretreatment for Enhancing Biomethane Production from Agro-Industrial, Agricultural and Catch Crop Biomasses

This study aimed to evaluate the effects of mechanical treatment through twin-screw extrusion for the enhancement of biomethane production. Four lignocellulosic biomasses (i.e., sweetcorn by-products, whole triticale, corn stover and wheat straw) were evaluated, and two different shear stress screw profiles were tested. Chemical composition, particle size reduction, tapped density and cellulose crystallinity were assessed to show the effect of extrusion pretreatment on substrate physico-chemical properties and their biochemical methane production (BMP) capacities. Both mechanical pretreatments allowed an increase in the proportion of particles with a diameter size less than 1 mm (from 3.7% to 72.7%). The most restrictive profile also allowed a significant solubilization of water soluble coumpounds, from 5.5% to 13%. This high-shear extrusion also revealed a reduction in cellulose crystallinity for corn stover (i.e., 8.6% reduction). Sweetcorn by-products revealed the highest BMP values (338–345 NmL/gVS), followed by corn stover (264–286 NmL/gVS), wheat straw (247–270 NmL/gVS) and whole triticale (233–247 NmL/gVS). However, no statistical improvement in maximal BMP production was provided by twin-screw extrusion. Nevertheless, BMP kinetic analysis proved that both extrusion pretreatments were able to increase the specific rate constant (from 13% to 56% for soft extrusion and from 66% to 107% for the high-shear one).

Effects of Biological and Chemical Degradation on the Properties of Scots Pine Wood-Part I: Chemical Composition and Microstructure of the Cell Wall.

Research on new conservation treatment for archaeological wood requires large amounts of wooden material. For this purpose, artificial wood degradation (biological—using brown-rot fungus Coniophora puteana, and chemical—using NaOH solution) under laboratory conditions was conducted to obtain an abundance of similar samples that mimic naturally degraded wood and can serve for comparative studies. However, knowledge about its properties is necessary to use this material for further study. In this study, the chemical composition and microstructure of degraded cell walls were investigated using FT-IR, XRD, helium pycnometry and nitrogen absorption methods. The results show that biological degradation caused the loss of hemicelluloses and celluloses, including the reduction in cellulose crystallinity, and led to lignin modification, while chemical degradation mainly depleted the amount of hemicelluloses and lignin, but also affected crystalline cellulose. These changes affected the cell wall microstructure, increasing both surface area and total pore volume. However, the chemical degradation produced a greater number of mesopores of smaller size compared to fungal decomposition. Both degradation processes weakened the cell wall’s mechanical strength, resulting in high shrinkage of degraded wood during air-drying. The results of the study suggest that degraded wood obtained under laboratory conditions can be a useful material for studies on new consolidants for archaeological wood.

Highly crystalline cotton spinning wastes utilization: Pretreatment, optimized hydrolysis and fermentation using Pleurotus florida for bioethanol production

Due to highly deleterious effects of physico-chemical pretreatment of lignocellulosic biomass to environment, the 2G biofuel production requires more sustainable and eco-friendly approach. During this study, the effect of biological pretreatment on fibrous cotton spinning waste mixture (CSWM) was investigated using solid-state cultivation of white-rot fungi, Pleurotus florida. The pretreatment with P. florida showed significant amount of lignin degradation (∼60 %w/w) and ∼80–85% of cellulose crystallinity reduction with the cellulose content of 80.7%w/w, after 14 days of pretreatment. This was also evidenced by Attenuated Total Resonance – Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy (SEM). Optimization of hydrolysis conditions using Central Composite Design (CCD) resulted in the R-squared (R2) value and desirability of 0.97 and 0.95, respectively. The optimized conditions were biomass loading of 0.67%w/v and enzyme loading of 60 FPU/g of cellulose results in hydrolysis efficiency of ∼70% after 96 h. The hydrolysate, supplemented with mineral salts and 3 %v/v of inoculum, were maintained at anaerobic conditions with 32 ± 2℃ for 72 h. Optimum ethanol yield of 64 % (1.18 g/L) was obtained after 60 h of fermentation. This finding suggests that microbial pretreatment can effectively be employed for the sustainable and green production of bioethanol with more economical value.

Pretreatment strategies for enhanced biogas production from lignocellulosic biomass

The inclusion of a pretreatment step in anaerobic digestion processes increases the digestibility of lignocellulosic biomass and enhances biogas yields by promoting lignin removal and the destruction of complex biomass structures. The increase in surface area enables the efficient interaction of microbes or enzymes, and a reduction in cellulose crystallinity improves the digestion process under anaerobic conditions. The pretreatment methods may vary based on the type of the lignocellulosic biomass, the nature of the subsequent process and the overall economics of the process. An improved biogas production by 1200% had been reported when ionic liquid used as pretreatment strategy for anaerobic digestion. The different pretreatment techniques used for lignocellulosic biomasses are generally grouped into physical, chemical, physicochemical, and biological methods. These four modes of pretreatment on lignocellulosic biomass and their impact on biogas production process is the major focus of this review article.

Enhanced hydrolysis and acidification of cellulose at high loading for methane production via anaerobic digestion supplemented with high mobility nanobubble water

In this study, CH4 production from anaerobic digestion (AD) of refractory cellulose was investigated at a high loading of 3.5 (VScellulose/VSinoculum) under nanobubble water (NBW) addition. A longer proton spin-spin relaxation time (2611–2906 ms) of NBW during 35 days’ storage reflected its high mobility and diffusion of water molecules. Higher volatile fatty acids were yielded at the hydrolysis-acidification stage under NBW addition. Methanogenesis tests showed that Air-NBW and CO2-NBW supplementation accelerated the utilization of crystalline cellulose, achieving methane yields of 264 and 246 mL CH4/g-VSreduced, increasing by 18% and 10% compared to deionized water addition (the control), respectively. In addition, under NBW addition the cellulose crystallinity reduction was enhanced by 14–20% with microbial community being enriched with hydrolytic and methanogenic bacteria. Results from this work suggest that NBW environment with no chemical addition and relatively low energy consumption is advantageous for enhanced AD process of cellulosic biomass.

A novel FC17/CESA4 mutation causes increased biomass saccharification and lodging resistance by remodeling cell wall in rice

BackgroundRice not only produces grains for human beings, but also provides large amounts of lignocellulose residues, which recently highlighted as feedstock for biofuel production. Genetic modification of plant cell walls can potentially enhance biomass saccharification; however, it remains a challenge to maintain a normal growth with enhanced lodging resistance in rice.ResultsIn this study, rice (Oryza sativa) mutant fc17, which harbors the substitution (F426S) at the plant-conserved region (P-CR) of cellulose synthase 4 (CESA4) protein, exhibited slightly affected plant growth and 17% higher lodging resistance compared to the wild-type. More importantly, the mutant showed a 1.68-fold enhancement in biomass saccharification efficiency. Cell wall composition analysis showed a reduction in secondary wall thickness and cellulose content, and compensatory increase in hemicelluloses and lignin content. Both X-ray diffraction and calcofluor staining demonstrated a significant reduction in cellulose crystallinity, which should be a key factor for its high saccharification. Proteomic profiling of wild-type and fc17 plants further indicated a possible mechanism by which mutation induces cellulose deposition and cell wall remodeling.ConclusionThese results suggest that CESA4 P-CR site mutation affects cell wall features especially cellulose structure and thereby causes enhancement in biomass digestion and lodging resistance. Therefore, CESA4 P-CR region is promising target for cell wall modification to facilitate the breeding of bioenergy rice.

Solid-state fermentation of oil palm frond petiole for lignin peroxidase and xylanase-rich cocktail production.

In current practice, oil palm frond leaflets and stems are re-used for soil nutrient recycling, while the petioles are typically burned. Frond petioles have high commercialization value, attributed to high lignocellulose fiber content and abundant of juice containing free reducing sugars. Pressed petiole fiber is the subject of interest in this study for the production of lignocellulolytic enzyme. The initial characterization showed the combination of 0.125mm frond particle size and 60% moisture content provided a surface area of 42.3m2/g, porosity of 12.8%, and density of 1.2g/cm3, which facilitated fungal solid-state fermentation. Among the several species of Aspergillus and Trichoderma tested, Aspergillus awamori MMS4 yielded the highest xylanase (109IU/g) and cellulase (12IU/g), while Trichoderma virens UKM1 yielded the highest lignin peroxidase (222IU/g). Crude enzyme cocktail also contained various sugar residues, mainly glucose and xylose (0.1-0.4g/L), from the hydrolysis of cellulose and hemicellulose. FT-IR analysis of the fermented petioles observed reduction in cellulose crystallinity (I900/1098), cellulose-lignin (I900/1511), and lignin-hemicellulose (I1511/1738) linkages. The study demonstrated successful bioconversion of chemically untreated frond petioles into lignin peroxidase and xylanase-rich enzyme cocktail under SSF condition.

Effect of Fenton and photo‐Fenton pretreatments on solubilization of lignocellulosic biomass

Non‐edible lignocellulosic biomass materials are attracting increasing attention as renewable, economical, and abundant resources to reduce dependency on petroleum resources and minimize energy and material feedstock costs. Despite their potential, the complex and rigid structures of these materials limit their use in such applications. Biomass materials must first be broken down into components with smaller molecular weights (e.g., oligo‐ and monosaccharides) in order to be efficiently converted into a wide range of value‐added products. Hydrolysates from biomass can be used for producing various value‐added products, including biofuels (ethanol, hydrogen, etc.), industrially important chemicals (e.g., solvents), and food products (sugar and sugar alcohols, etc.).Success of using lignocellulosic biomass for biofuels and other useful chemical productions depend largely upon pretreatment and break down methods applied as well as physical and chemical properties of the biomass. The pretreatment is an essential prerequisite to make biomass accessible and reactive by altering its structural features such as, removal of lignin and reduction of cellulose crystallinity, which thereby increases in porosity. The goal of this project was to evaluate Fenton and photo‐Fenton processes as pretreatments methods for biomass (corn stover and corn husk) solubilization and reduce extensive use of toxic and hazardous chemicals or energy inputs in the hydrolysis process. Fenton and Fenton‐UV experiments were carried out in a glass reactor using 100 mL pH=3 solution (HCl). The biomass (2.5g) and 1mmol Fe2+ were added as well as freshly prepared H2O2 solution (3 × 0.7 mmol H2O2; 15 min intervals). In the Fenton‐UV reaction, light source (Pen Ray 254 nm, 40W) was placed in the center of the reactor. Further hydrolysis of Fenton and Fenton‐UV treated samples occurred using mild acid hydrolysis (4% H2SO4) to calculate hydrolysis percentage of each filtered mixture and biomass residue. IR and SEM measurements were performed on solid biomass residue and hydrolysate was analyzed for total organic carbon (TOC) content. The hydrolysis percentage between different pretreatments showed that Fenton in corn stover and corn husk resulted in 3.8% and 1.6% hydrolysis respectively while the Fenton‐UV‐Acid hydrolysis treatment in corn stover and corn husk resulted in 32.4% and 51.8% hydrolysis. From this we concluded that Fenton‐UV‐Acid hydrolysis was the best pretreatment for the solubilization of corn biomass.Support or Funding InformationUniversity of Nebraska‐Lincoln: Undergraduate Creative Activities and Research Experience.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Facile isothermal solid acid catalyzed ionic liquid pretreatments to enhance the combined sugars production from Arundo donax Linn.

BackgroundSolid acid catalyzed inexpensive ionic liquid (IL) pretreatment is promising because of its effectiveness at decreasing biomass recalcitrance to subsequent enzymatic hydrolysis or in situ hydrolysis of carbohydrate oligomers. However, the conventional strategy was limited by the complex non-isothermal process and considering only one aspect of sugar recovery. In this study, facile isothermal pretreatments using Amberlyst 35DRY catalyzed 1-n-butyl-3-methylimidazolium chloride ([C4mim]Cl) at mild conditions were developed on bioenergy crop Arundo donax Linn. to enhance the combined sugars released. The physicochemical differences, enzymatic digestibility, and sugars released in situ were evaluated and compared to define the best set of conditions.ResultsThe optimized isothermal pretreatment (110 °C, IL for 3 h, Amberlyst for 1 h) resulted in significant enhancement in combined sugars released (58.4 g/100 g raw materials), recovering 85.0 % of the total reducing glycan in the raw biomass. This remarkable improvement could be correlated to cellulose crystallinity reduction, crystalline conversion, and partial removal of the main chemical components caused by the pretreatment. Particularly, solubilization of hemicelluloses and partial depolymerization of cellulose contributed to the synergetic improvement of sugars production in enzymatic hydrolysis and in situ. Irrespective of the generous differences in mass recovery, the highest cellulose digestibility of 90.2 % and sugar released of 43.0 % (based on initial materials) in the pretreatment liquor were obtained. Interestingly, lignin (0.8–6.1 %) and sugars derived lactic acid (4.70–5.94 %) were produced without any notable deleterious effects.ConclusionsIsothermal [C4mim]Cl-Amberlyst pretreatment was a highly effective, simple, and convenient process that produced high yields of fermentable sugars from recalcitrant biomass by in situ hydrolysis of soluble biomass and enhancement of cellulose digestibility of the regenerated biomass. Relatively high amount of new revenues beyond sugars of this pretreatment could promote the commercial viability.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0589-8) contains supplementary material, which is available to authorized users.

An Effective Conversion of Cotton Waste Biomass to Ethanol: A Critical Review on Pretreatment Processes

Cotton based textile industries are one of the major source of revenue to the Indian economy. India contributes around 30 % of world’s total cotton cultivation every year. Cotton accounts for more than 70 % of total textile production in the country. Cotton is subjected to various processes to produce cotton based textile apparels. During the processing of cotton, more amount of cotton-based wastes are generated and they are landfilled or incinerated, in general. Cotton textile industries are facing critical problems on solid-waste management, which results in environmental pollution and health hazards. These wastes comprise lignin, hemicellulose and cellulose, which can be utilized as sustainable feedstock for the production of bioethanol. Cotton based lignocellulosic biomass requires specific pretreatment strategy to efficiently remove lignin and to solubilize hemicellulose, which increases the accessibility of hydrolytic enzymes during saccharification. Till date, various pretreatment technologies such as physical, physico-chemical, acid/alkali-, ionic liquids (ILs) and biological treatment methods are widely evaluated for lignin removal, hemicellulose solubilization and cellulose crystallinity reduction in cotton wastes to enhance the enzymatic hydrolysis and fermentation process. This paper reviews about different pretreatment methods implemented and its significance for the conversion of cotton wastes to bioethanol.

Quantitative proteomics reveals protein profiles underlying major transitions in aspen wood development.

BackgroundWood development is of outstanding interest both to basic research and industry due to the associated cellulose and lignin biomass production. Efforts to elucidate wood formation (which is essential for numerous aspects of both pure and applied plant science) have been made using transcriptomic analyses and/or low-resolution sampling. However, transcriptomic data do not correlate perfectly with levels of expressed proteins due to effects of post-translational modifications and variations in turnover rates. In addition, high-resolution analysis is needed to characterize key transitions. In order to identify protein profiles across the developmental region of wood formation, an in-depth and tissue specific sampling was performed.ResultsWe examined protein profiles, using an ultra-performance liquid chromatography/quadrupole time of flight mass spectrometry system, in high-resolution tangential sections spanning all wood development zones in Populus tremula from undifferentiated cambium to mature phloem and xylem, including cell expansion and cell death zones. In total, we analyzed 482 sections, 20–160 μm thick, from four 47-year-old trees growing wild in Sweden. We obtained high quality expression profiles for 3,082 proteins exhibiting consistency across the replicates, considering that the trees were growing in an uncontrolled environment. A combination of Principal Component Analysis (PCA), Orthogonal Projections to Latent Structures (OPLS) modeling and an enhanced stepwise linear modeling approach identified several major transitions in global protein expression profiles, pinpointing (for example) locations of the cambial division leading to phloem and xylem cells, and secondary cell wall formation zones. We also identified key proteins and associated pathways underlying these developmental landmarks. For example, many of the lignocellulosic related proteins were upregulated in the expansion to the early developmental xylem zone, and for laccases with a rapid decrease in early xylem zones. We observed upregulation of two forms of xylem cysteine protease (Potri.002G005700.1 and Potri.005G256000.2; Pt-XCP2.1) in early xylem and their downregulation in late maturing xylem. Our data also show that Pt-KOR1.3 (Potri.003G151700.2) exhibits an expression pattern that supports the hypothesis put forward in previous studies that this is a key xyloglucanase involved in cellulose biosynthesis in primary cell walls and reduction of cellulose crystallinity in secondary walls.ConclusionOur novel multivariate approach highlights important processes and provides confirmatory insights into the molecular foundations of wood development.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2458-z) contains supplementary material, which is available to authorized users.

Effectiveness of fungal treatment by Coprinopsis cinerea and Polyporus tricholoma on degradation and methane yields of lignocellulosic grass

The effectiveness of fungal treatment by Coprinopsis cinerea and Polyporus tricholoma on biodegradability and methane yield of paragrass was investigated. After 15 days fungal treatment, reduction in cellulose crystallinity was found in grass treated with C. cinerea and P. tricholoma. The maximum methane production rate occurred at day 10 for the grass treated with C. cinerea, day 13 for the grass treated with P. tricholoma, and day 22 for the untreated grass. However, after 140 day anaerobic digestion, the methane yield of the grass treated by C. cinerea and by P. tricholoma was approximately 15% lower than that of the untreated grass, which was 368 mL STP/g VS added. Using two-stage fungal treatment and anaerobic digestion, the recalcitrant cellulose in the fungal treated grass was significantly lower than that of the untreated grass (P < 0.05), while the amounts of recalcitrant hemicellulose were approximately the same.

Experimental investigation of ionic liquid pretreatment of sugarcane bagasse with 1,3-dimethylimadazolium dimethyl phosphate

In this study, an imidazolium-based ionic liquid (IL), 1,3-dimethylimidazolium dimethyl phosphate ([Mmim][DMP]), was applied for pretreating sugarcane bagasse to produce bioethanol. The main goal of this study was to investigate the feasibility of bagasse pretreatment with this IL, and to verify the effect of different operational parameters on the pretreatment process. Results indicated that temperature and duration of IL-pretreatment have optimum values. Within the range investigated, a maximum fermentable sugar conversion of 70.38% was achieved with this IL at 120°C and 120min. The corresponding value was 28.65% for the untreated biomass. The main cause for the observed enhancement in enzymatic hydrolysis was the reduction of cellulose crystallinity in the IL-pretreated biomass, as compared to the untreated sample, because it resulted in higher accessibility of the enzymes to the biomass after pretreatment. Moreover, the results indicated that aqueous [Mmim][DMP] mixtures are not as effective for pretreatment as the pure IL.

Rice Straw Based Evaluation of Lignolytic and Cellulolytic Capabilities of Novel Strains of Saprophytic Fungi from Indo-Burma Biodiversity Hotspot

Superior lignocellulolytic microbes are useful for efficient bioconversion of plant biomass. Eight fungal strains were isolated from compost and forest litter of an Indo-Burma Biodiversity hotspot and were evaluated for their lignolytic and cellulolytic capabilities. X-ray diffraction (XRD) study was performed to test their effect on cellulose crystallinity of rice straw. Scanning electron spectroscopic (SEM) and Fourier transform-infrared (FT-IR) spectroscopic analysis were performed to study the surface morphology and chemical changes occurred in the fungi treated rice straw, respectively. The fungus Fusarium equiseti strain TWRF-10 showed endoglucanase, exoglucanase, and endoxylanase activity of 99.19, 87.39, and 166.81 IU g–1 rice straw, respectively, whereas Penicillium simplicissimum strain TRF-27 showed laccase and Mn peroxidase activity of 248.53 and 168.5 IU g–1 rice straw, respectively. The strain TRF-27 caused a 65% reduction in cellulose crystallinity. These strains should be further tested for industrial use.

Different response between woody core and bark of goat willow (Salix caprea L.) to concentrated phosphoric acid pretreatment followed by enzymatic saccharification

Different response between woody core and bark of goat willow biomass to concentrated phosphoric acid pretreatment prior to enzymatic saccharification was investigated as changes of chemical compositions, carbohydrate compositions, and crystallinity of cellulose before and after pretreatment. Goat willow has different chemical composition between bark and woody core, higher polysaccharides content in woody core as 74.6% compared with 61.0% in bark. In bark, hydrophobic and hydrophilic extractives contents was 20.4% compared with 8.1% in woody core.Parts of extractives and carbohydrates were removed by concentrated phosphoric acid pretreatment, and this trend was more obvious in bark than woody core. In bark, 60% of xylan and 30% of cellulose was removed by acid pretreatment but only 40% of xylan and 8.3% of cellulose in woody core. Removal of polysaccharides in cell wall and destruction of crystal structure (cellulose crystallinity reduction) in cellulose caused the more enzymatic saccharification by commercial cellulases cocktails. Bark showed three times higher cellulose to glucose conversion by cellulases but woody core was two times higher than those of untreated.

Quantitative characterization of the impact of pulp refining on enzymatic saccharification of the alkaline pretreated corn stover

In this work, corn stover was refined by a pulp refining instrument (PFI refiner) after NaOH pretreatment under varied conditions. The quantitative characterization of the influence of PFI refining on enzymatic hydrolysis was studied, and it was proved that the enhancement of enzymatic saccharification by PFI refining of the pretreated corn stover was largely due to the significant increment of porosity of substrates and the reduction of cellulose crystallinity. Furthermore, a linear relationship between beating degree and final total sugar yields was found, and a simple way to predict the final total sugar yields by easily testing the beating degree of PFI refined corn stover was established. Therefore, this paper provided the possibility and feasibility for easily monitoring the fermentable sugar production by the simple test of beating degree, and this will be of significant importance for the monitoring and controlling of industrial production in the future.

Protic acid resin enhanced 1-butyl-3-methylimidazolium chloride pretreatment of Arundo donax Linn.

To improve the cellulose digestibility of energy crop Arudo donax Linn. with cost-efficient, a novel pretreatment of protic acid resin Amberlyst 35DRY catalyzed inexpensive ionic liquid (IL) 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) was developed in this work. The pretreatment was performed at 160°C with [C4mim]Cl for 1.5h, followed by Amberlyst 35DRY catalyzed at 90°C for 1h. The IL-Amberlyst pretreatment was demonstrated to be effective, evidenced by the reduction in cellulose crystallinity (31.4%) and increased porosity caused by extensive swelling the undissolved biomass and partial depolymerization of the longer cellulose chain of the dissolved biomass by Amberlyst. Consequently, a higher glucose yield (92.8%) was obtained than for the single [C4mim]Cl pretreatment (42.8%) at an enzyme loading of 20FPU/g substrate. Overall, the enhanced pretreatment was competitive by using inexpensive and recyclable IL-Amberlyst 35DRY pretreated system with shorter processing time and reduced enzyme usage.

Ionic liquids as a tool for lignocellulosic biomass fractionation

Abstract Lignocellulosic biomass composes a diversity of feedstock raw materials representing an abundant and renewable carbon source. In majority lignocellulose is constituted by carbohydrate macromolecules, namely cellulose and hemicellulose, and by lignin, a polyphenilpropanoid macromolecule. Between these biomacromolecules, there are several covalent and non-covalent interactions defining an intricate, complex and rigid structure of lignocellulose. The deconstruction of the lignocellulosic biomass makes these fractions susceptible for easier transformation to large number of commodities including energy, chemicals and material within the concept of biorefinery. Generally, the biomass pre-treatment depends on the final goal in the biomass processing. The recalcitrance of lignocellulose materials is the main limitation of its processing once the inherent costs are excessively high for the conventional pre-treatments. Furthermore, none of the currently known processes is highly selective and efficient for the satisfactory and versatile use, thus, new methodologies are still studied broadly. The ionic liquid technology on biomass processing is relatively recent and first studies were focused on the lignocellulosic biomass dissolution in different ionic liquids (ILs). The dissolution in IL drives to the structural changes in the regenerated biomass by reduction of cellulose crystallinity and lignin content contrasting to the original biomass. These findings provided ILs as tools to perform biomass pre-treatment and the advantageous use of their specific properties over the conventional pre-treatment processes. This review shows the critical outlook on the study of biomass dissolution and changes occurred in the biomass during this process as well as on the influence of several crucial parameters that govern the dissolution and further pre-treatment process. The review of currently known methods of biomass fractionation in IL and aqueous-IL mixtures is also discussed here and perspectives regarding these topics are given as well.