Dilute sulfuric acid hydrolysis of sugar maple wood extract at atmospheric pressure

Principal factors affecting the yield of dilute acid pretreatment of lignocellulosic biomass: A critical review

This review provides a critical analysis of the state of the art of dilute acid pretreatment applied to lignocellulosic biomass. Data from 63 publications were extracted and analysed. The majority of the papers used residence times of<30 min, temperature ranges from 100 °C to 200 °C, and acid levels between 0 % and 2 %. Yields are quantified directly after pretreatment (xylose content) or after enzymatic hydrolysis (glucose content). Statistical analyses allowed the time-temperature equivalence to be quantified for three types of biomass: they were formulated by non-linear expressions. In further works, investigating less explored areas, for example moderate temperature levels with longer residence times, is recommended. Pretreatment material (time-temperature kinetics, reactor type) and analytical methods should be standardized and better described. It becomes mandatory to promote the development of an open, findable, accessible, interoperable, and reusable data approach for pretreatments research.

Substrate concentration: A more serious consideration than the amount of 5-hydroxymethylfurfural in acid-catalyzed hydrolysis during bioethanol production from starch biomass

5-hydroxymethylfurfural (5-HMF) yield during bioethanol production from starch was determined using spectrophotometry and chromatography. Increasing acid concentration and time favored 5-HMF production with HCl while yield decreased after 45-minute hydrolysis time for HNO₃ and H₂SO₄ hydrolyzed samples. Impacts of glucose (substrate) concentration and produced 5-HMF on bioethanol yield were studied with different sulphuric acid concentrations and different α-amylase and amyloglucosidase activities. A central composite rotational design was utilized to determine the conditions of hydrolysis for optimum glucose production. The results showed that maximum glucose yield occurred at 0.5 M acid concentration and 45-minute hydrolysis time, while maximum yield was achieved at 120 and 280 units of α-amylase and amyloglucosidase activities respectively. It was shown that 5-HMF did not exhibit much inhibition on ethanol yield at low acid concentrations but became pronounced at higher acid concentrations, while high glucose concentrations had a pronounced negative effect on ethanol yield and fermentation efficiency.

Current Ethanol Production Requirements for the Yeast Saccharomyces cerevisiae

An increase in global energy demand has caused oil prices to reach record levels in recent times. High oil prices together with concerns over CO₂ emissions have resulted in renewed interest in renewable energy. Nowadays, ethanol is the principal renewable biofuel. However, the industrial need for increased productivity, wider substrate range utilization, and the production of novel compounds leads to renewed interest in further extending the use of current industrial strains by exploiting the immense, and still unknown, potential of natural yeast strains. This review seeks to answer the following questions: (a) which characteristics should S. cerevisiae have for the current production of first- and second-generation ethanol? (b) Why are alcohol-tolerance and thermo-tolerance characteristics required? (c) Which genes are related to these characteristics? (d) What are the advances that can be achieved with the isolation of new organisms from the environment?

A Novel and Effective Recyclable BiOCl/BiOBr Photocatalysis for Lignin Removal from Pre-Hydrolysis Liquor

The presence of lignin hampers the utilization of hemicelluloses in the pre-hydrolysis liquor (PHL) from the kraft-based dissolving pulp production process. In this paper, a novel process for removing lignin from PHL was proposed by effectively recycling catalysts of BiOCl/BiOBr. During the whole process, BiOCl and BiOBr were not only adsorbents for removing lignin, but also photocatalysts for degrading lignin. The results showed that BiOCl and BiOBr treatments caused 36.3% and 33.9% lignin removal, respectively, at the optimized conditions, and the losses of hemicellulose-derived saccharides (HDS) were both 0.1%. The catalysts could be regenerated by simple photocatalytic treatment and obtain considerable CO and CO2. After 15 h of illumination, 49.9 μmol CO and 553.0 μmol CO2 were produced by BiOCl, and 38.7 μmol CO and 484.3 μmol CO2 were produced by BiOBr. Therefore, both BiOCl and BiOBr exhibit excellent adsorption and photocatalytic properties for lignin removal from pre-hydrolysis.

Modified Rhamnogalacturonan-Rich Apple Pectin-Derived Structures: The Relation between Their Structural Characteristics and Emulsifying and Emulsion-Stabilizing Properties

In the context of the increasing interest in natural food ingredients, the emulsifying and emulsion-stabilizing properties of three rhamnogalacturonan-rich apple pectin-derived samples were assessed by evaluating a range of physicochemical properties. An apple pectin (AP74) was structurally modified by a β-eliminative reaction to obtain a RG-I-rich pectin sample (AP-RG). Subsequent acid hydrolysis of AP-RG led to the generation of pectin material with partially removed side chains (in particular arabinose depleted) (AP-RG-hydrolyzed), thus exhibiting differences in rhamnose, arabinose, and galactose in comparison to AP-RG. All samples exhibited surface activity to some extent, especially under acidic conditions (pH 2.5). Furthermore, the viscosity of the samples was assessed in relation to their emulsion-stabilizing properties. In a stability study, it was observed that the non-degraded AP74 sample at pH 2.5 exhibited the best performance among all the apple pectin-derived samples evaluated. This emulsion presented relatively small oil droplets upon emulsion production and was less prone to creaming than the emulsions stabilized by the (lower molecular weight) RG-I-rich materials. The AP-RG and AP-RG-hydrolyzed samples presented a slightly better emulsion stability at pH 6.0 than at pH 2.5. Yet, neither pectin sample was considered having good emulsifying and emulsion-stabilizing properties, indicated by the presence of coalesced and flocculated oil droplets.

Dilute acid hydrolysis of wastes of fruits from Amazon for ethanol production

<abstract> <p>This study carried out the screening of wastes from Amazon plants to produce hydrolysates with a high monosaccharides content for ethanol production. Initially, we hydrolyzed (diluted acid) Amazon wastes (peel from the fruit of <italic>Astrocaryum aculeatum</italic> Meyer, peel from the fruit of <italic>Bactris gasipaes</italic> Kunth, straw obtained from endocarp of the fruit of <italic>Euterpe oleracea</italic> Mart., peel from the fruit of <italic>Theobroma grandiflorum</italic> Schumann and peel from the root of <italic>Manihot esculenta</italic> Crant) to obtain hydrolysates with the high content of fermentable sugars. Then, we investigated by 2³ factorial design the influence of the factors: a) hydrolysis time (min); b) H₂SO₄-to-waste ratio (g/g) and c) solid-to-liquid ratio (g/mL) in the variables reducing sugars and furans. The hydrolysis of the peel of the fruit of <italic>Bactris gasipaes</italic> resulted in the highest concentration of reducing sugars (23.7 g/L). After detoxification and concentration process, the <italic>Bactris gasipaes</italic> hydrolysate results in 96.7 g/L of reducing sugars largely fermentable (90%) by <italic>Saccharomyces cerevisiae</italic> PE-2. The experimental design demonstrated that the factors H₂SO₄-to-waste ratio (g/g) and solid-to-liquid ratio (g/mL) were the most significant affecting the final content of reducing sugars and furans in the hydrolysate of the peel of <italic>Bactris gasipaes</italic>. Hydrolysis time of 4.4 min, H₂SO₄-to-waste ratio of 0.63 g/g, and the solid-to-liquid ratio of 0.17 g/mL resulted in the concentration of reducing sugars of 49 g/L. This study shows the potential of peels from the fruit of <italic>Bactris gasipaes</italic> to produce ethanol.</p> </abstract>

Integrated wood biorefinery: Improvements and tailor-made two-step strategies on hydrolysis techniques

This study categorized different pretreatment methods into mild (below 120 °C), normal (120-200 °C) and extreme conditions (above 200 °C) for selective approach with efficient wood hydrolysis for direct market applications. The model two-step strategy of selective normal-hydrolysis: steam explosion (170 °C for 30 min) with concentrating normal-hydrolysis: organosolv at (160 °C for 20 min) on hard/softwood will delivery individual fractions of hemicellulose, lignin, and cellulose with recovery rate above 95%. The first step releases C5 sugars with a recovery rate of 80% followed by the second step for C6 sugars with 95% rate and direct use of reduced sugars into C5 and C6 value-added products. The categorized conditions will ease the selection of the pretreatment method for the wood type and model strategy will increase the hydrolysis rate with greater simplicity and validity. The integrated wood biorefinery with two-step treatment is an in-house and closed-loop with endless industrial applications.

In situ preparation of bacterial cellulose with antimicrobial properties from bioconversion of mulberry leaves

It's long been understood that antimicrobial properties are one of the most important function in the field of biomedicine. In this thesis, we introduce a new technique to functionalize bacterial cellulose (BC) with antimicrobial properties by in situ method. We design a series of experiments on hydrolyzing mulberry leaves and exploring the methods of fermenting and purifying to obtain a BC complex with antimicrobial properties. Meanwhile, the anti-bacterial performances of MH-BC (fermented by the mulberry leaves acid hydrolysate fermentation medium) were evaluated with Escherichia coli and Staphylococcus aureus, and the experimental results showed that the MH-BC have excellent anti-bacterial activities. Considering the excellent biocompatibility of MH-BC towards hMSCs, we expect that this antibacterial functional BC composite will find potential applications in biomedicine and regenerative medicine.

Insights into the improvement of alkaline hydrogen peroxide (AHP) pretreatment on the enzymatic hydrolysis of corn stover: Chemical and microstructural analyses

The alkaline hydrogen peroxide (AHP) pretreatment (0.5 g H₂O₂/g corn stover, 30 °C, 24 h) removed 91.53% of the initial lignin and 55.77% of the initial hemicellulose in corn stover and afforded a considerable glucose yield (88.34%) through enzymatic hydrolysis. A combination of chemical and microstructural analyses was used to illustrate the mechanism of the effect of AHP pretreatment on enzymatic hydrolysis. During pretreatment, H₂O₂-derived radicals effectively spread into and destroyed the cell wall of various parts (vascular bundle sheath, xylem vessels, tracheid, phloem, and parenchyma) of corn stover to remove most of the lignin, acetyl group, and partial hemicellulose. They destroyed the compact structure of the cellulose-hemicellulose-lignin network, increased the cellulase-accessible pore volume by 6 times, doubled the area of exposed cellulose, and decreased the unproductive adsorption of enzymes onto lignin. Combining all the effects, AHP pretreatment effectively improved the cellulose accessibility to enhance the subsequent enzymatic hydrolysis efficiency.

Controlling the cleavage of the inter- and intra-molecular linkages in lignocellulosic biomass for further biorefining: A review

The abundant intermolecular linkages among cellulose, hemicellulose and lignin significantly limit the utilization of the most promising renewable biomass. Process control with solvents, catalysts and temperature is of significant importance providing ways to break the above linkages, and benefiting to the further conversion of the main biomass components to small molecular products. This article discusses the effect of catalyst under hydrothermal and organosolv treatment emphasizing the cleavage of the intermolecular linkage. Acidic catalysts show good performance on cleaving the linkages between carbohydrates and lignin. Basic catalysts promoted the dissolution of lignin component. Hydrogenolysis assisted conversion of lignin can efficiently break the intermolecular linkages to yield lignin-derived bio-oil, especially in co-solvent reaction system. Besides, the effects of single solvent and co-solvent systems, as well as the cleavage of the intramolecular linkages to yield target chemicals are also included. Several further study strategies are proposed.

Transformation of Sugar Maple Bark through Catalytic Organosolv Pulping

The catalytic organosolv pulping of sugar maple bark was performed adopting the concept of forest biorefinery in order to transform bark into several valuable products. Our organosolv process, consisting of pre-extracting the lignocellulosic material followed by pulping with ferric chloride as a catalyst, was applied to sugar maple bark. The pre-extraction step has yielded a mixture of phenolic extractives, applicable as antioxidants. The organosolv pulping of extractives-free sugar maple bark yielded a solid cellulosic pulp (42.3%) and a black liquor containing solubilized bark lignin (24.1%) and products of sugars transformation (22.9% of hemicelluloses), mainly represented by furfural (0.35%) and 5-hydroxymethyl furfural (HMF, 0.74%). The bark cellulosic pulp was determined to be mainly constituted of glucose, with a high residual lignin content, probably related to the protein content of the original bark (containing cambium tissue). The biorefinery approach to the transformation of a solid bark residue into valuable biopolymers (lignin and cellulose) along with phenolic antioxidants from pre-extraction and the HMF derivatives from black liquor (applicable for 2,5-diformylfuran production) is an example of a catalytic process reposing on sustainable engineering and green chemistry concepts.

Natural acetylation impacts carbohydrate recovery during deconstruction of Populus trichocarpa wood

BACKGROUND

Significant variation in the inherent degree of acetylation naturally exists in the xylem cell walls of Populus trichocarpa. During pretreatment, endogenous acetate hydrolyzes to acetic acid that can subsequently catalyze the breakdown of poplar wood, increasing the efficiency of biomass pretreatment.

RESULTS

Poplar genotypes varying in cell wall composition were pretreated in 0.3% H₂SO₄ in non-isothermal batch reactors. Acetic acid released from the wood was positively related to sugar release during pretreatment (R ≥ 0.9), and inversely proportional to the lignin content of the poplar wood (R = 0.6).

CONCLUSION

There is significant variation in wood chemistry among P. trichocarpa genotypes. This study elucidated patterns of cell wall deconstruction and clearly links carbohydrate solubilization to acetate release. Tailoring biomass feedstocks for acetate release could enhance pretreatment efficiencies.

Effect of the temperature on the dissolution of corn straw in ethanol solution

Hemicellulose, cellulose and lignin can be separated roughly and converted into sugars, chemicals and fractured lignin by adjusting the dissolution temperature.

Intensification effect of peroxide hydrogen on the complete dissolution of lignocellulose under mild conditions

Complete dissolution of corn straw was achieved in MSEW_SA+PHat 170 °C for 2.

Improvement membrane filterability in nanofiltration of prehydrolysis liquor of kraft dissolving pulp by laccase treatment

In this work, laccase treatment was employed to enhance nanofiltration process by lignin removal. Results showed that the membrane filterability was increased in terms of deionized water flux and PHL filtration process. On the other hand, the hemicellulosic sugars were negligible affected and can be concentrated to 172 g/L, which was increased about 300% from the original one. The combined laccase-nanofiltration process provides an alternative approach to utilize hemicellulosic sugars of PHL in an environmentally friendly way.

Optimization of glucose formation in karanja biomass hydrolysis using Taguchi robust method

The main objective of the present study is aimed to optimize the process parameters for the production of glucose from karanja seed cake. The Taguchi robust design method with L9 orthogonal array was applied to optimize hydrolysis reaction conditions and maximize sugar yield. Effect of temperature, acid concentration, and acid to cake weight ratio were considered as the main influencing factors which effects the percentage of glucose and amount of glucose formed. The experimental results indicated that acid concentration and liquid to solid ratio had a principal effect on the amount of glucose formed when compared to that of temperature. The maximum glucose formed was 245 g/kg extractive free cake.

Lignin removal enhancement from prehydrolysis liquor of kraft-based dissolving pulp production by laccase-induced polymerization

Lignin removal is essential for value-added utilization of hemicelluloses and acetic acid present in the prehydrolysis liquor (PHL) of a kraft-based hardwood dissolving pulp production. In this paper, a novel process concept, consisting of laccase-induced lignin polymerization, followed by filtration/flocculation, was developed to enhance the lignin removal. The results showed that the lignin removal increased from 11% to 46-61% at laccase concentration of 1-4 U mL(-1). The GPC results showed that the molecular weight of the lignin from the laccase treated PHL was increased by 160% in comparison with the original one. The subsequent flocculation using singular Poly-DADMAC system or dual polymer system of Poly-DADMAC/CPAM can further remove 10-15% lignin. The concentrations of hemicelluloses and acetic acid were negligibly affected during the laccase treatment, while flocculation caused 12-15% of total sugar loss. Additionally, the process incorporates this new concept into the kraft-based dissolving pulp production process was proposed.

Microbial heterotrophic production in an oligotrophic acidic geothermal lake: responses to organic amendments and terrestrial plant litter

Boiling Springs Lake (BSL) is an oligotrophic, acidic geothermal feature where even very low levels of microbial heterotrophic production still exceed autotrophy. To test whether allochthonous leaf litter (LL) inputs fuel this excess, we quantified leaf litterfall, leaching and decomposition kinetics, and measured the impact of organic amendments on production, germination and cell growth, using pyrosequencing to track changes in microbial community composition. Coniferous leaves in BSL exhibited high mass loss rates during leaching and decomposition, likely due to a combination of chemical hydrolysis and contributions of both introduced and endemic microbes. We measured very low in situ (3)H-thymidine incorporation over hours by the dominant chemolithotroph Acidimicrobium (13-65 μg C L(-1) day(-1)), which was inhibited by simple C sources (acetate, glucose). Longer term incubations with additions of 0.01-0.02% complex C/N sources induced germination of the Firmicute Alicyclobacillus within 1-2 days, as well as growth of Acetobacteraceae after 3-4 days. LL additions yielded the opposite successional patterns of these r-selected heterotrophs, boosting production to 30-150 μg C L(-1) day(-1). Growth and germination studies suggest both prokaryotes and fungi likely consume allochthonous organics, and might be novel sources of lignocellulose-degrading enzymes. A model of BSL's C budget supports the hypothesis that allochthonous inputs fuel seasonal microbial heterotrophy, but that dissolved organic C sources greatly exceed direct LL inputs.

Butanol production from hemicellulosic hydrolysate of corn fiber by a Clostridium beijerinckii mutant with high inhibitor-tolerance

A Clostridium beijerinckii mutant RT66 with considerable inhibitor-tolerance obtained by continuous culture was used for butanol production from non-detoxified hemicellulosic hydrolysate of corn fiber treated with dilute sulfuric acid (SAHHC). In fed-batch fermentation, 1.8L of diluted SAHHC containing 10 g/L of reducing sugar was provided during the acidogenic phase and 0.2L of concentrated SAHHC containing 300 g/L of reducing sugar was provided during the solventogenic phase. The mutant produced a total amount of solvents of 12.9 g/L, which consisted of 3.1 g/L of acetone, 9.3 g/L of butanol and 0.5 g/L of ethanol. A solvent yield of 0.35 g/g sugar and a productivity of 0.18 g/L h in 72 h were achieved. The remarkable inhibitor-tolerance of C. beijerinckii RT66 demonstrates that this may be an excellent strain for butanol production from ligocellulosic materials.

Evaluation of hardboard manufacturing process wastewater as a feedstream for ethanol production

Waste streams from the wood processing industry can serve as feedstream for ethanol production from biomass residues. Hardboard manufacturing process wastewater (HPW) was evaluated on the basis of monomeric sugar recovery and fermentability as a novel feedstream for ethanol production. Dilute acid hydrolysis, coupled with concentration of the wastewater resulted in a hydrolysate with 66 g/l total fermentable sugars. As xylose accounted for 53 % of the total sugars, native xylose-fermenting yeasts were evaluated for their ability to produce ethanol from the hydrolysate. The strains selected were, in decreasing order by ethanol yields from xylose (Y p/s, based on consumed sugars), Scheffersomyces stipitis ATCC 58785 (CBS 6054), Pachysolen tannophilus ATCC 60393, and Kluyveromyces marxianus ATCC 46537. The yeasts were compared on the basis of substrate utilization and ethanol yield during fermentations of the hydrolysate, measured using an HPLC. S. stipitis, P. tannophilus, and K. marxianus produced 0.34, 0.31, and 0.36 g/g, respectively. The yeasts were able to utilize between 58 and 75 % of the available substrate. S. stipitis outperformed the other yeast during the fermentation of the hydrolysate; consuming the highest concentration of available substrate and producing the highest ethanol concentration in 72 h. Due to its high sugar content and low inhibitor levels after hydrolysis, it was concluded that HPW is a suitable feedstream for ethanol production by S. stipitis.

Estimation of inhibitory effects of hemicellulosic wood hydrolysate inhibitors on PHA production by Burkholderia cepacia ATCC 17759 using response surface methodology

Sugar maple hemicellulosic hydrolysate was utilized as a renewable feedstock for polyhydroxyalkanoates production by Burkholderia cepacia ATCC 17759. To estimate inhibitory effects of the hydrolysate, response surface methodology was utilized to analyze cell growth and PHA accumulation in the presence of multiple inhibitors. Mixture design was employed to study the correlation between the proportion of phenolics and total inhibition. The resultant models (R(2) as 92.42% and 93.14% for cell growth and PHA production, respectively) indicated syringic acid was the most inhibitory among three phenolics and synergistic inhibition was observed for the combinations of vanillin/syringic acid and vanillic acid/syringic acid. When furfural, levulinic acid, and acetate were also present during the fermentation, central composite design was employed. The regression model using 48 h cell growth as the response surface (R(2)=87.82%) showed acetate was the most inhibitory. Additionally, strong synergistic effects were observed for the combinations of acetate/phenolics and levulinic acid/furfural.

A comparison of dilute aqueous p-toluenesulfonic and sulfuric acid pretreatments and saccharification of corn stover at moderate temperatures and pressures

Single step pretreatment-saccharification of corn stover was investigated in aqueous p-toluenesulfonic and sulfuric acid media. Dilute aqueous solution of p-toluenesulfonic acid was a better catalyst than aqueous sulfuric acid of the same H(+) ion concentration for single step pretreatment-saccharification of corn stover at moderate temperatures and pressures. For example, 100mg corn stover heated at 150°C for 1h in 0.100 M H(+) aqueous sulfuric acid produced 64 μmol of total reducing sugars (TRS), whereas the sample heated in 0.100 M H(+)p-toluenesulfonic acid produced 165 μmol of TRS under identical conditions. Glucose yield showed a similar trend, as aq. sulfuric acid and p-toluene sulfonic acid media produced 29 and 35 μmol of glucose respectively after 2.5h. Higher catalytic activity of p-toluenesulfonic acid may be due to an interaction with biomass, supported by repulsion of hydrophobic tolyl group by the aqueous phase.

One step conversion of wheat straw to sugars by simultaneous ball milling, mild acid, and fungus Penicillium simplicissimum treatment

Wheat straw is one of the major lignocellulosic plant residues in many countries including China. An attractive alternative is the utilization of wheat straw for bioethanol production. This article mainly studies a simple one-step wet milling with Penicillium simplicissimum and weak acid to hydrolysis of wheat straw. The optimal condition for hydrolysis was ball milling 48 h in citrate solvent (pH = 4) with P. simplicissimum H5 at the speed of 500 rpm and the yield of sugar increased with increased milling time. Corresponding structure transformations before and after milling analyzed by X-ray diffraction, transmission Fourier transform infrared spectroscopy, and environmental scanning electron microscopy clearly indicated that this combined treatment could be attributed to the crystalline and chemical structure changes of cellulose in wheat straw during ball milling. This combined treatment of ball milling, mild acid, and fungus hydrolysis enabled the conversion of the wheat straw. Compared with traditional method of ball milling, this work showed a more simple, novel, and environmentally friendly way in mechanochemical treatment of wheat straw.

Production of polyhydroxyalkanoates by Burkholderia cepacia ATCC 17759 using a detoxified sugar maple hemicellulosic hydrolysate

Sugar maple hemicellulosic hydrolysate containing 71.9 g/l of xylose was used as an inexpensive feedstock to produce polyhydroxyalkanoates (PHAs) by Burkholderia cepacia ATCC 17759. Several inhibitory compounds present in wood hydrolysate were analyzed for effects on cell growth and PHA production with strong inhibition observed at concentrations of 1 g/l furfural, 2 g/l vanillin, 7 g/l levulinic acid, and 1 M acetic acid. Gradual catabolism of lower concentrations of these inhibitors was observed in this study. To increase the fermentability of wood hydrolysate, several detoxification methods were tested. Overliming combined with low-temperature sterilization resulted in the highest removal of total inhibitory phenolics (65%). A fed-batch fermentation exhibited maximum PHA production after 96 h (8.72 g PHA/L broth and 51.4% of dry cell weight). Compositional analysis by NMR and physical–chemical characterization showed that PHA produced from wood hydrolysate was composed of polyhydroxybutyrate (PHB) with a molecular mass (M  N) of 450.8 kDa, a melting temperature (T  m) of 174.4°C, a glass transition temperature (T  g) of 7.31°C, and a decomposition temperature (T  decomp) of 268.6°C.

Hydrolysis of cellulose in SO₃H-functionalized ionic liquids

Influence of acidity and structure of ionic liquids on microcrystalline cellulose (MCC) hydrolysis was investigated. MnCl₂-containing ionic liquids (ILs) were efficient catalysts and achieved MCC conversion rates of 91.2% and selectivities for 5-hydroxymethyl furfural (HMF), furfural and levulinic acid (LA) of 45.7%, 26.2% and 10.5%, respectively. X-ray diffractometry indicated that catalytic hydrolysis of MCC in ionic liquids resulted in the changes to MCC crystallinity and transformation of cellulose I into cellulose II. SO₃H-functionalized ionic liquids showed higher activities than non-functionalized ILs. The simplicity of the chemical transformation of cellulose provides a new approach for the use this polymer as raw material for renewable energy and chemical industries.

Dilute phosphoric acid-catalysed hydrolysis of municipal bio-waste wood shavings using autoclave parr reactor system

The visibility of using municipal bio-waste, wood shavings, as a potential feedstock for ethanol production was investigated. Dilute acid hydrolysis of wood shavings with H₃PO₄ was undertaken in autoclave parr reactor. A combined severity factor (CSF) was used to integrate the effects of hydrolysis times, temperature and acid concentration into a single variable. Xylose concentration reached a maximum value of 17 g/100 g dry mass corresponding to a yield of 100% at the best identified conditions of 2.5 wt.% H₃PO₄, 175 °C and 10 min reaction time corresponding to a CSF of 1.9. However, for glucose, an average yield of 30% was obtained at 5 wt.% H₃PO₄, 200 °C and 10 min. Xylose production increased with increasing temperature and acid concentration, but its transformation to the degradation product furfural was also catalysed by those factors. The maximum furfural formed was 3 g/100 g dry mass, corresponding to the 24% yield.

Improvement in HPLC separation of acetic acid and levulinic acid in the profiling of biomass hydrolysate

5-Hydroxymethylfurfural (HMF) and furfural could be separated by the Aminex HPX-87H column chromatography, however, the separation and quantification of acetic acid and levulinic acid in biomass hydrolysate have been difficult with this method. In present study, the HPLC separation of acetic acid and levulinic acid on Aminex HPX-87H column has been investigated by varying column temperature, flow rate, and sulfuric acid content in the mobile phase. The column temperature was found critical in resolving acetic acid and levulinic acid. The resolution for two acids increased dramatically from 0.42 to 1.86 when the column temperature was lowered from 60 to 30 °C. So did the capacity factors for levulinic acid that was increased from 1.20 to 1.44 as the column temperature dropped. The optimum column temperature for the separation was found at 45 °C. Variation in flow rate and sulfuric acid concentration improved not as much as the column temperature did.

Separation of lignocellulosic materials by combined processes of pre-hydrolysis and ethanol extraction

In this paper, we proposed a new modification for an ethanol-based pulping process, which would consist of the pre-hydrolysis (pre-extraction) of wood chips for removing hemicelluloses; the ethanol extraction of pre-hydrolyzed wood chips for removing lignin; and the post purification of cellulose, leading to the production of pure cellulose. We also experimentally evaluated the separation of hemicelluloses from the pre-hydrolysis liquor (PHL) obtained from a pulp mill. To remove lignin from the PHL, it was acidified to a pH of 2, which resulted in 47% lignin precipitation. The lignin separation from the acidified PHL was further improved via adding polyethylene oxide and poly aluminum chloride or adding ethyl acetate. To recover the hemicelluloses from the acidified PHL, ethanol was added to the acidified PHL with a volumetric ratio of 4 to 1. The isolated lignin and hemicelluloses were characterized by a Fourier transform infrared spectroscopy (FTIR) and a gas permeation chromatography (GPC).