Pretreated Biomass Research Articles

Genome sequencing and analysis of Xylaria sp. L1 provides novel insights into its utilization in IDF decomposition in okara

This study investigated the genome ofXylaria sp. L1 and its application in assisting the degradation of okara, which is an agricultural waste. The fungus process showed that there was a 50.31% cellulose loss and 56.25% hemicellulose loss, respectively. In merely 7 days, compared with untreated control, the content of insoluble dietary fiber (IDF) in the substrate was significantly decreased by 62% whereas that of soluble dietary fiber (SDF) significantly increased by 413%. Importantly, the activity of cellulase showed a continuous increase trend and it reached the maximum activity at 11.37U/g on the 7th day. The pretreated biomass showed much higher levels of polysaccharides, especially for glucuronic acid (63.63%), than the untreated controls after 7 days. Additionally, Xylaria sp. L1 sporocarps had higher quantities of macronutrients, especially for Zn. Furthermore, we conducted the first annotation of Xylaria sp. L1 genome. Illumina and nanopore sequencing revealed that the genome size of Xylaria sp. L1 was 36.61 Mb. The high activity of cellulase was in accordance with the annotation the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Eukaryotic Orthologous Groups (KOG), and carbohydrate-active enzymes (CAZy) databases, which are related to cellulose and hemicellulose degradation. GHs were the most abundant enzymes and 203 genes were annotated to GHs. Cellulose and hemicellulose decomposition was likely performed by an expressed GH43 and GH5 protein families containing their binding domains and genes A0779, A0819, A7717 played an important role in pentose and glucuronate interconversions. Therefore, the higher IDF decomposition by Xylaria sp. L1 makes it a prospective feedstock for okara degradation.

Prediction of pyrolysis kinetics for torrefied biomass based on raw biomass properties and torrefaction severity

Torrefaction is a thermal pretreatment of biomass at mild temperatures to upgrade the fuel properties. The torrefied biomass consists of residual chemical structures after partial decomposition; therefore, its pyrolysis kinetics largely inherit those of raw biomass. This study proposed a novel kinetic model for pyrolysis of torrefied biomass, established from three-parallel reaction model (TPRM) of raw biomass. Three structural changes caused by torrefaction were incorporated into the model. First, the residual lignocellulosic composition was estimated using the TPRM. Second, the partial decomposition of weaker chemical bonds was considered using the cumulative Rayleigh distribution with a scale parameter determined from the residual lignocellulosic components. Third, the increase in the amount of fixed carbon due to char-forming reactions was treated by a correlation acquired from the experimental data. When applied to hinoki cypress, kenaf, and wood pellets at various torrefaction severities, the proposed model accurately reproduced the pyrolysis kinetics of torrefied biomass. The prediction quality (R2) for typical torrefaction severities was greater than 0.9967 and 0.9833, respectively, depending on the correlation of fixed carbon used for individual biomass and the average trend. In the latter, the model required only a single thermogravimetric analysis to derive all model parameters at any torrefaction severity.

The Role of Mild Alkaline Pretreatment in the Biorefinery Upgrade of Spent Coffee Grounds

This work proposes a valorization route for spent coffee grounds (SCG), a widespread lignocellulosic residue, encompassing the production of: biomethane, lignin, and oligosaccharides as value-added products obtained simultaneously during a mild alkaline (NaOH) pretreatment. The studied operational variables were the reaction time (60–240 min), temperature (25–75 °C), and the NaOH concentration (0–2.5 M). The severity factor suitably describes the global process kinetics, with higher severities (log Mo = 5.5) yielding high product yields, 18.02% and 13.25% (on dry SCG basis) for lignin and oligosaccharides (XGMOS), respectively. Solid yield is negatively impacted by all studied variables (at the 95% confidence level). Conversely, XGMOS yield is positively influenced both by time and catalyst concentration, whereas lignin yield is only (positively) influenced by catalyst concentration. Optimal balance between product formation and potential operational costs is putatively achieved when using 0.625 M NaOH, at 50 °C for 60 min. The mild alkaline pretreated biomass (MAP-SCG) was compared to untreated SCG for biomethane production by anaerobic co-digestion with pig slurry (PS), using a ratio of biomass/PS = 1/3 (volatile solids (VS) basis). The proposed valorization route enabled the sequential production of 6.25 kg lignin, 6.36 kg oligosaccharides, and 138.05 kg biomethane per 100 kg of non-extracted SCG (and 287.60 kg pig slurry), in an integrated process that is technically feasible and promotes the circular bioeconomy.

Recovery of mixture of hydroxyethylammonium carboxylate protic ionic liquids from sugarcane pretreatment liquor using activated carbon in a fixed bed column

Integrated strategies using fixed bed columns can facilitate the recovery of protic ionic liquids (PILs) used in the pretreatment of lignocellulosic biomass. In this study, we investigated the adsorption of 2-hydroxyethylammonium acetate [Mea][Ac] and 2-hydroxyethylammonium hexanoate [Mea][Hex] on activated carbon in a fixed bed column for recovering the PILs mixture present in the liquor of the pretreatment. Breakthrough curves were determined experimentally. Breakthrough time (tb), exhaustion time (te), difference between tb and te, adsorption efficiency (ϕads), column efficiency (ϕcol) and qe equilibrium capacity were evaluated as a function of simultaneous variations in superficial velocity (vs) and temperature (T) using a central composite rotatable design. The optimum conditions for PIL purification were vs = 1.66 cm/min (Q = 1.3 mL/min) and T = 20 °C. After selection of optimum operating conditions, PILs separation was evaluated in a model solution and sugarcane pretreatment liquor, with similar intervals for recover of PILs. This is the first study to develop a successful proof of concept of mixture PILs [Mea][Ac]/[Mea][Hex] recovery from sugarcane straw pretreatment liquor in a fixed-bed column of activated carbon. The results indicate that the method has great potential for industrial application.

Adaptive laboratory evolution of Bacillus subtilis to overcome toxicity of lignocellulosic hydrolysate derived from Distiller's dried grains with solubles (DDGS)

Microbial tolerance to toxic compounds formed during biomass pretreatment is a significant challenge to produce bio-based products from lignocellulose cost effectively. Rational engineering can be problematic due to insufficient prerequisite knowledge of tolerance mechanisms. Therefore, adaptive laboratory evolution was applied to obtain 20 tolerant lineages of Bacillus subtilis strains able to utilize Distiller's Dried Grains with Solubles-derived (DDGS) hydrolysate. Evolved strains showed both improved growth performance and retained heterologous enzyme production using 100% hydrolysate-based medium, whereas growth of the starting strains was essentially absent. Whole-genome resequencing revealed that evolved isolates acquired mutations in the global regulator codY in 15 of the 19 sequenced isolates. Furthermore, mutations in genes related to oxidative stress (katA, perR) and flagella function appeared in both tolerance and control evolution experiments without toxic compounds. Overall, tolerance adaptive laboratory evolution yielded strains able to utilize DDGS-hydrolysate to produce enzymes and hence proved to be a valuable tool for the valorization of lignocellulose.

Production of ethanol from pretreated biomass of Chlorella sorokiniana raised at lab and pilot scales

Production of ethanol from pretreated biomass of Chlorella sorokiniana raised at lab and pilot scales

Agricultural waste biomass for sustainable bioenergy production: Feedstock, characterization and pre-treatment methodologies

The worldwide trend in energy production is moving toward circular economy systems and sustainable availability of sources. Some advanced methods support the economic development of energy production by the utilization of waste biomass, while limiting ecological effects. The use of agro waste biomass is viewed as a major alternative energy source that expressively lowers greenhouse gas emissions. Agricultural residues produced as wastes after each step of agricultural production are used as sustainable biomass assets for bioenergy production. Nevertheless, agro waste biomass needs to go through a few cyclic changes, among which biomass pre-treatment contributes to the removal of lignin and has a significant role in the efficiency and yield of bioenergy production. As a result of rapid innovation in the utilization of agro waste for biomass-derived bioenergy, a comprehensive overview of the thrilling highlights and necessary advancements, in addition to a detailed analysis of feedstock, characterization, bioconversion, and contemporary pre-treatment procedures, appear to be vital. To this end, the current status in the generation of bioenergy from agro biomass through various pre-treatment procedures was examined in this study, along with presenting relevant challenges and a perspective for future investigations.

Plant Genotype and Fungal Strain Harmonization Improves Miscanthus sinensis Conversion by the White-Rot Fungus Ceriporiopsis subvermispora

Fungal pretreatment of plant biomass is often assessed by using single plant genotypes and single fungal strains, but can the process be improved by harmonizing both, thus selecting specific substrate–fungus combinations? To tackle this question, we treated four Miscanthus sinensis genotypes with four Ceriporiopsis subvermispora strains and thoroughly analyzed substrates and treated residues. The M. sinensis genotypes differed in cellulose, hemicellulose, and lignin contents and lignin-wise diverged in subunit and linkage composition and the incorporation of hydroxycinnamic acids and tricin. Independently of the M. sinensis genotype used, C. subvermispora strain MES13904 outperformed the other three strains in extent and selectivity of delignification and consistently generated the highest enzymatic residual carbohydrate conversion and structural changes in the residual lignin. The “best” substrate–fungus combination gave 63% w/w delignification and a total enzymatic glucose yield of 66% w/w, while the “worst” combination led to 3% w/w lignin removal only and negligible glucose yield improvement. Our study highlights that white-rot fungal treatment of plant biomass is driven by both compositional and structural features of the substrate as well as the genetic makeup of the fungal strain used. These insights contribute to expediting the biological valorization of lignocellulose and ultimately to enabling more controlled fungal pretreatments.

Fungal Selectivity and Biodegradation Effects by White and Brown Rot Fungi for Wood Biomass Pretreatment.

The biodegradation path and mechanism of wood varies depending on diverse fungi and tree species, as fungi possess selectivity in degradation of versatile wood components. This paper aims to clarify the actual and precise selectivity of white and brown rot fungi and the biodegradation effects on different tree species. Softwood (Pinus yunnanensis and Cunninghamia lanceolata) and hardwood (Populus yunnanensis and Hevea brasiliensis) were subjected to a biopretreating process by white rot fungus Trametes versicolor, and brown rot fungi Gloeophyllum trabeum and Rhodonia placenta with various conversion periods. The results showed that the white rot fungus Trametes versicolor had a selective biodegradation in softwood, which preferentially convert wood hemicellulose and lignin, but cellulose was retained selectively. Conversely, Trametes versicolor achieved simultaneous conversion of cellulose, hemicellulose and lignin in hardwood. Both brown rot fungi species preferentially converted carbohydrates, but R. placenta had a selectivity for the conversion of cellulose. In addition, morphological observation showed that the microstructures within wood changed significantly, and the enlarged pores and the improved accessibility could be beneficial for the penetration and accessibility of treating substrates. The research outcomes could serve as fundamental knowhows and offer potentials for effective bioenergy production and bioengineering of bioresources, and provide a reference for further application of fungal biotechnology.

Competitive interactions of NH3 and toluene with biochar modified by pre- and post-treatments of H3PO4 in dual adsorption systems

Biochar modified by H3PO4 treatment can be used to purify malodorous gases during bio-drying of sludge, but the current understanding of multi-component adsorption of malodorous gases through biochar is limited. This study examined the adsorption mechanism of mixed malodorous gases including toluene and ammonia (NH3) on two kinds of biochar modified via H3PO4 pretreatment before and after pyrolysis. The biochar obtained by H3PO4 pretreatment of biomass before pyrolysis (C550) preferred to adsorb NH3 whether in the single or the dual system. In contrast, the biochar obtained by H3PO4 reprocessing after pyrolysis of biomass (C350-550) tended to adsorb toluene in the dual system but was more efficient in absorbing NH3 in the single system. The pseudo-second-order kinetic model indicated the synergistic adsorption between NH3 and toluene for all biochar samples. In-situ DRIFTS of C350-550 during adsorption demonstrated the formation of amino functional groups caused by NH3 chemical adsorption with -OH (or -COOH) in the dual system. These increases in basic groups on C350-550 could enhance the surface zero potential point of C350-550, thereby improving the non-polarity of C350-550 and benefit the adsorption of weak polar toluene.

Identification of Optimal Binders for Torrefied Biomass Pellets

The pretreatment of biomass through torrefaction is an effective means of improving the fuel quality of woody biomass and its suitability for use in existing facilities burning thermal coal. Densification of torrefied biomass produces a fuel of similar energy density, moisture content, and fixed carbon content to low-grade coals. Additionally, if the torrefaction conditions are optimized, the produced torrefied pellet will be resistant to weathering and biological degradation, allowing for outdoor storage and transport in a manner similar to coal. In untreated biomass, lignin is the primary binding agent for biomass pellets and is activated by the heat and pressures of the pellet extrusion process. The thermal degradation of lignin during torrefaction reduces its binding ability, resulting in pellets of low durability not suitable for transportation. The use of a binding agent can increase the durability of torrefied pellets/briquettes through a number of different binding mechanisms depending on the binder used. This study gives a review of granular binding mechanisms, as they apply to torrefied biomass and assesses a variety of organic and inorganic binding agents, ranking them on their applicability to torrefied pellets based on a number of criteria, including durability, hydrophobicity, and cost. The best binders were found to be solid lignin by-product derived from pulp and paper processing, biomass tar derived from biomass pyrolysis, tall oil pitch, and lime.

Microbial xylanase aided biobleaching effect on multiple components of lignocelluloses biomass based pulp and paper: a review

Abstract Due to discharge of hazardous organochlorine compounds and absorbable organic halogen compounds in the effluent, the pulp and paper industries are trying to alter the bleaching process to limit the use of chlorine compounds and comply with regulatory, environmental, and market demands. With progress in biotechnology, enzyme technologies can effectively pre-treat lignocellulosic biomass in the pulp and paper making process. Usually, these enzymatic processes reduce the environmental impact of traditional pulp and paper-making processes, lower the overall production cost, and enhance product quality. Microbial xylanases are the potential bio-bleaching candidate due to their renewable, mild operating, highly specific, and eco-friendly nature. Xylanase enhances the efficacy of the bleaching process by breaking the β-1, 4-glycosidic backbone of the re-precipitated xylan network and removing the trapped lignin from the pulp fibers. Xylanolytic action positively influences the kappa number, hexenuronic acid, chromophore compounds release, pulp crystallinity, morphology and many other attributes of pulp. The present review comprehensively highlights the microbial xylanolytic system, its mechanism, and its application in pulp bioleaching. With the recent development, the paper delineates the xylanase-aided bleaching effects on pulp, paper, and effluent attributes aimed to reduce bleaching chemical use, AOX formation, and energy use in the pulp refining process.

Biphasic lignocellulose fractionation for staged production of cellulose nanofibers and reactive lignin nanospheres: A comparative study on their microstructures and effects as chitosan film reinforcing

The effective fractionation of lignocellulose and the enhancement of its components require formidable efforts. This study explored synergistic biorefinery routes for the holistic conversion of lignocellulose biomass to green nanomaterials through one-pot fractionation using recyclable p-toluenesulfonic acid (p-TsOH)/pentanol reagents. The potential of p-TsOH/pentanol pretreatment of aspen biomass under various temperatures (80–180 °C) for co-production of cellulose nanofibers (CNFs) and lignin nanospheres (LNSs) was investigated. The optimal pretreatment temperature, which minimizes cellulosic degradation and promotes the holistic conversion of biomass, was 120 °C. In addition to its highly digestible nature, the cellulose-rich residue produced high-quality CNFs with a diameter <100 nm, good crystallization, and thermostability, making it suitable for various applications. Lignin characterization, molecular dynamics simulation, and density functional theory analyses of the recovered lignin revealed well-protected β-O-4 bonds (47.3/100 Ar), uniform molecular weights (Mw, 2815 g/mol; Mn, 1704 g/mol; PDI, 1.65), < 1% sugar content, fewer condensed structures, and nanosize shapes (100–300 nm) due to the molecular interactions of p-TsOH and pentanol with lignin units. Moreover, 0.4% LNSs additions reduced the chitosan film thickness by 53% and enhanced its tensile strain and strength by 33 and 59%, respectively, as compared to the pure chitosan film. This study provides a sustainable platform for the co-production of biobased CNFs and LNSs using cutting-edge fractionation of LCB, which is a breakthrough toward industrial biorefineries.

Autofermentation of alkaline cyanobacterial biomass to enable biorefinery approach

BackgroundCarbon capture using alkaliphilic cyanobacteria can be an energy-efficient and environmentally friendly process for producing bioenergy and bioproducts. The inefficiency of current harvesting and downstream processes, however, hinders large-scale feasibility. The high alkalinity of the biomass also introduces extra challenges, such as potential corrosion, inhibitory effects, or contamination of the final products. Thus, it is critical to identify low cost and energy-efficient downstream processes.ResultsAutofermentation was investigated as an energy-efficient and low-cost biomass pre-treatment method to reduce pH to levels suitable for downstream processes, enabling the conversion of cyanobacterial biomass into hydrogen and organic acids using cyanobacteria’s own fermentative pathways. Temperature, initial biomass concentration, and oxygen presence were found to affect yield and distribution of organic acids. Autofermentation of alkaline cyanobacterial biomass was found to be a viable approach to produce hydrogen and organic acids simultaneously, while enabling the successful conversion of biomass to biogas. Between 5.8 and 60% of the initial carbon was converted into organic acids, 8.7–25% was obtained as soluble protein, and 16–72% stayed in the biomass. Interestingly, we found that extensive dewatering is not needed to effectively process the alkaline cyanobacterial biomass. Using natural settling as the only harvesting and dewatering method resulted in a slurry with relatively low biomass concentration. Nevertheless, autofermentation of this slurry led to the maximum total organic acid yield (60% C mol/C mol biomass) and hydrogen yield (326.1 µmol/g AFDM).ConclusionAutofermentation is a simple, but highly effective pretreatment that can play a significant role within a cyanobacterial-based biorefinery platform by enabling the conversion of alkaline cyanobacterial biomass into organic acids, hydrogen, and methane via anaerobic digestion without the addition of energy or chemicals.

Laccase in Biorefinery of Lignocellulosic Biomass

Biorefinery has emerged in recent years as an alternative to petrorefinery, as biofuels have all the potential to replace fossil fuels for the sustainable development of human society. From this aspect, lignocellulosic biomasses are the most important, since these are the most abundant ubiquitous most raw material on earth, which can be converted into biofuels such as bioethanol, biobutanol, biohydrogen, biogas, etc. There are several strategies for conversion, such as biochemical, thermochemical, and microbial conversions of biomasses to biofuels; however, each of the strategies has its own consequences. Enzymatic conversion of biomasses into sugars, and thereby into bioethanol, is considered as the most sustainable way. However, biomass recalcitrance to enzymatic hydrolysis is the biggest challenge, as cellulose, hemicellulose, and lignin are intricately attached to each other making their separation a tedious task. Pretreatment is necessary to partially remove or change the form of lignin to make cellulose and hemicellulose accessible to enzymes. Most of the pretreatment methods are designed to target lignin, as it is the major component responsible for recalcitrance nature of biomasses. Laccase is a versatile lignin-degrading or lignin-modifying enzyme which is secreted by filamentous fungi and bacteria, and is reported for the biological pretreatment of biomasses, which is the most sustainable way of pretreatment. However, the rate of the reaction is extremely slow making it less attractive. This article will give an insight into the biorefinery of biomasses, with the special significance to laccase.

Design and characterization of a multi-frequency semi-pilot ultrasonic reactor: Application to the extraction and oxidation of flaxseed-gum

The aim of this study was to design and study a new multi-frequency ultrasonic semi-pilot tank by evaluating the operational parameters with respect to calorimetric efficiency and sonochemical activity. The device was then applied to the extraction of flax-gum from the seeds and its oxidation by TEMPO method. The ultrasonic tank was used in single and multi-frequency modes (20 kHz, 40 kHz and 100 kHz). It has been shown that in single mode, the geometry and location of the ultrasonic transducers had a direct impact on the energy transfer efficiency and that the immersed radial probes gave transfer rates in the range of 66.9–82.8%. The production rate of molecular iodine was found to be better at a frequency of 100 kHz whatever the output powers used. The extraction of polysaccharides from flax seeds is proportional to the power density and can be done under mild conditions to preserve the integrity of macromolecules. Ultrasound assisted oxidation is efficient and we have highlighted that this could be done at low acoustic powers thank to the 100 kHz frequency. Thus, the results show that ultrasonic vessels are relevant for the scaling up of pretreatment of biomass and chemical processes.

Morphological and thermal stability characteristics of oil palm frond and trunk by ultrasound-low alkali-based pretreatment

Oil palm fronds and trunks leave a lot of lignocellulosic residues in the agricultural field. Due to its highly complex chemical composition, the lignocellulosic matrix is difficult to break down. This study aims to investigate the effects of chemo-physical pretreatment of oil palm fronds and trunks with ultrasound in a low alkali concentration solution. The microstructure and thermal stability of the oil palm frond and trunk were investigated using scanning electron microscopy (SEM) and a thermogravimetric (TG) method. SEM analysis proved the deterioration of the lignocellulose matrix of the ultrasound-assisted alkali pretreatment compared to raw. According to the TG results, the decomposition temperature curve of treated oil palm shifted to the right side after 50 percent mass degradation, indicating more excellent thermal stability than untreated oil palm biomass. On the other hand, at a temperature above 350 °C, the pretreated biomass has less thermal stability. It has been demonstrated that a combination of low chemical concentration and physical pretreatments can disrupt the oil palm lignocellulose microstructure and potentially shorten the time required to achieve maximum hydrolysis efficiency. Furthermore, ultrasonication power of 300 W, frequency of 40 kHz, temperature of 80 °C, and time of 30 min in combination with low alkali-based pretreatment in oil palm residue will be helpful in applications requiring greater thermal stability.

Effects of raw and hydrolysed Nannochloropsis gaditana biomass included at low level in finishing diets for gilthead seabream (Sparus aurata) on fillet quality and shelf life

Numerous studies evaluating the effects of the incorporation of microalgae in feeds have reported favourable impacts on different physiological aspects of aquacultured fish. Although productivity is the major goal in terms of profitability in fish farming, qualitative aspects are gaining the attention of producers, given the relevance of quality attributes related to organoleptic parameters, proximal composition, and shelf life on the commercial value of fish. Indeed, microalgae are acknowledged for their richness in substances with potential positive effects on all those quality attributes. In this context, this study assesses the effects of finishing diets enriched with the microalga Nannochloropsis gaditana, either crude or enzymatically hydrolysed, on several quality parameters of gilthead seabream (Sparus aurata) fillets. Two inclusion levels (2.5 and 5%) of raw and enzymatically hydrolysed microalgal biomass were incorporated into diets, plus a microalgae-free control diet, and a 42-day feeding trial was carried out on fish of commercial size (approx. 500 g body weight). The influence of the experimental diets on fish biometry, fillet quality parameters, and shelf life was evaluated. The results indicate, overall, that microalgae-enriched diets yielded favourable, dose-dependent effects on several objective quality parameters of fillets, namely, improved fatty acid profile, reduced microbial counts, enhanced lipid oxidative status, and improved textural and skin colour attributes. Although the enzymatic pre-treatment of the microalgal biomass was expected to impact positively its functional effects on all quality parameters, however, no general trend was observed.

Integrated process to produce biohydrogen from wheat straw by enzymatic saccharification and dark fermentation

In this study, different pretreatment methods, including lyophilization, hydrothermal pretreatment, and ultrasound combined with dilute alkali post-cooking, were investigated to enhance the efficiency of enzymatic saccharification and biohydrogen production of the wheat straw. All pretreatment methods could effectively remove lignin and hemicellulose while retaining cellulose, further enhancing the biomass accessibility for subsequently enzymatic saccharification and biohydrogen production. A reducing sugar concentration of 13.18 g/L was acquired when wheat straw was treated with ultrasound and dilute alkali cooking (RU). The sequential fermentative hydrogen yield of the substrate RU was 133.6 mL/g total solids (TS), which was 5.6-fold larger than that of the raw material (23.9 mL/g TS). The study confirmed that ultrasound combined with dilute alkali cooking was an effective method, which not only provided significant guideline for improving biohydrogen production but also presented helpful direction for the efficient pretreatment of other lignocellulosic biomass.

Pretreatment of Mulberry Twig using Nonionic Surfactant-assisted Ionic Liquid for Zymolysis and Subsequent Bioethanol Production

A natural cellulosic biomass pretreatment process was established to use ionic liquid (IL) for efficient zymolysis and subsequent bioethanol production, the IL 1, 3-Dimethylimidazolium dimethyl phosphate/Tween-80 ([Mmim][DMP]/T80) was selected in view of its high pretreatment function. The productivity of reducing sugars from mulberry twigs pretreated with the IL at 130°C for 0.33 h reached 74.72% after zymolysis for 48 h, while only a 14.62% conversion rate for the sample pretreated by water. The fermentability character of the hydrolyzate, witdrawn from zymolysis, was fermented into bioethanol using Saccharomyces cerevisiae. This kind of microbe could efficiently utilize glucose to produce ethanol with the yield of 0.382 g/g glucose in 30 h fermentation. In conclusion, the ionic liquid pretreatment at low temperatures shows promise as a pretreatment reagent for natural lignocellulosic biomass.