Study on Saccharification of Saccharum spontaneum L. by Sulphuric Acid Hydrolysis

In order to improve the saccharification rate by acid hydrolysis in the technique for production of ethanol from biomass, in this study, Saccharum spontaneum L. was used as the experimental material to investigate the rules and technological conditions for two-step acid-hydrolysis saccharification by single factor experiment and orthogonal experiment. According to the results, concentrated sulfttric acid hydrolysis was the first step, with the liquid-solid ratio of 42： 1, sulfuric acid concentration of 70%, hydrolysis time of 20 rain, and hydrolysis temperature of 55 ℃ ; dilute sulphuric acid hydrolysis was the second step, with the liquidsolid ratio of 115： 1, sulfuric acid concentration of 5.5%, hydrolysis time of 155 min, and hydrolysis temperature of 100℃. In two-step acid hydrolysis process, the yield of reducing sugar was 48.78%. The results indicated that two-step acid-hydrolysis saccharification required mild conditions, simple operation and low cost, and led to high reducing sugar yield, exhibiting a broad application prospect.

Preparation of κ-carra-Oligosaccharides with Microwave Assisted Acid Hydrolysis Method

A rapid method of microwave assisted acid hydrolysis was established to prepare κ-carra-oligosaccharides. The optimal hydrolysis condition was determined by an orthogonal test. The degree of polymerization （DP） of oligosaccharides was detected by high performance thin layer chromatography （HPTLC） and polyacrylamide gel electrophoresis （PAGE）. Considering the results of HPTLC and PAGE, the optimum condition of microwave assisted acid hydrolysis was determined. The concentration of κ-carrageenan was 5 mgmL-1; the reaction solution was adjusted to pH 3 with diluted hydrochloric acid; the solution was hydrolyzed under microwave irradiation at 100 ℃ for 15 min. Oligosaccharides were separated by a Superdex 30 column （2.6 cm × 90 em） using AKTA Purifier UPC100 and detected with an online refractive index detector. Each fraction was characterized by electrospray ioni- zation mass spectrometry （ESI-MS）. The data showed that odd-numbered κ-carra-oligosaccharides with DP ranging from 3 to 21 could be obtained with this method, and the structures of the oligosaccharides were consistent with those obtained by traditional mild acid hydrolysis. The new method was more convenient, efficient and environment-friendly than traditional mild acid hydrolysis. Our results provided a useful reference for the preparation of oligosaceharides from other polysaccharides.

Optimization of dilute acid hydrolysis of Enteromorpha

Acid hydrolysis is a simple and direct way to hydrolyze polysaccharides in biomass into fermentable sugars. To produce fermentable sugars effectively and economically for fuel ethanol, we have investigated the hydrolysis of Enteromorpha using acids that are typically used to hydrolyze biomass： H2SO4, HC1, H3PO4 and C4H404 （maleic acid）. 5%（w/w） Enteromorpha biomass was treated for different times （30, 60, and 90 min） and with different acid concentrations （0.6, 1.0, 1.4, 1.8, and 2.2%, w/w） at 121~C. H2SO4 was the most effective acid in this experiment. We then analyzed the hydrolysis process in H2SO4 in detail using high performance liquid chromatography. At a sulfuric acid concentration of 1.8% and treatment time of 60 min, the yield of ethanol fermentable sugars （glucose and xylose） was high, （230.5 mg/g dry biomass, comprising 175.2 mg/g glucose and 55.3 mg/g xylose）, with 48.6% of total reducing sugars being ethanol fermentable. Therefore, Enteromorpha could be a good candidate for production of fuel ethanol. In future work, the effects of temperature and biomass concentration on hydrolysis, and also the fermentation of the hydrolysates to ethanol fuel should be focused on.

Isolation of Thermally Stable Cellulose Nanocrystals from Spent Coffee Grounds via Phosphoric Acid Hydrolysis

As the world's population exponentially grows,so does the need for the production of food,with cereal production growing annually from an estimated 1.0 billion to 2.5 billion tons within the last few decades.This rapid growth in food production results in an ever increasing amount of agricultural wastes,of which already occupies nearly 50%of the total landfill area.For example,is the billions of dry tons of cellulose-containing spent coffee grounds disposed in landfills annually.This paper seeks to provide a method for isolating cellulose nanocrystals(CNCs)from spent coffee grounds,in order to recycle and utilize the cellulosic waste material which would otherwise have no applications.CNCs have already been shown to have vast applications in the polymer engineering field,mainly utilized for their high strength to weight ratio for reinforcement of polymer-based nanocomposites.A successful method of purifying and hydrolyzing the spent coffee grounds in order to isolate usable CNCs was established.The CNCs were then characterized using current techniques to determine important chemical and physical properties.A few crucial properties determined were aspect ratio of 12±3,crystallinity of 74.2%,surface charge density of(48.4±6.2)mM/kg cellulose,and the ability to successfully reinforce a polymer based nanocomposite.These characteristics compare well to other literature data and common commercial sources of CNCs.

The Crystalline Changes of Starch from Rhizoma Dioscorea by Acid Hydrolysis

The changes in crystalline properties of starch from Rhizoma Dioscorea by acid hydrolysis was characterized by X-Ray diffractometry （XRD）. The results revealed that the crystalline type of Rhizoma Dioscorea starch changed from C-type to A-type after 16 days of the acid hydrolysis. This phenomenon was different from that of other starches subjected to the acid hydrolysis. The results revealed that the B-polymorphs of C-type starch constituted the amorphous regions while the crystalline areas were mainly composed of A-polymorphs. The degree of crystallinity of the acid-thinned starch increased gradually with the time of acid hydrolysis.

Pyrolysis of Banana and Coffee Residues after Acid Hydrolysis

The use of the residues from renewable feedstock, besides the production of fuels, but also for the generation of other chemicals products, has become a priority. Superior plants have considerable potential as carbohydrate, aryl and fatty acids sources. However, the separation of the main constituents of the samples is necessary for several purposes in the biorefinery concept. The acid hydrolysis and pyrolysis processes are very promising technology, however, some adjustments in the conditions of pyrolysis are needed for different biomasses since carbohydrates were detected （14%-17%） in the residues after the conventional acid hydrolysis of these uncommon biomasses （coffee husk and banana stem and stalk）. On the other hand, it was showed that, by pyrolysis, it is possible to obtain from the solid residue after acid hydrolysis： pyrogenic carbon （charcoal with a yield of 48.5%-52.7%） for agriculture use （biochar） and valuable chemicals in the pyrolysis oil biooil fraction （that accounted by 26.4%-29.0%, free of water）, such as lignin monomers （32.6%-56.4% of the bio-oil） and fatty acids （30%-52.5%）.

Effect of Ultra-Turrax on Nanocellulose Produced by Acid Hydrolysis and Modified by Nano ZnO by Sol-Gel Method

Cellulose nanocrystals (NCC) and cellulose nanofibrils (CNF) were obtained by a single step process, with synergy between 64% sulfuric acid hydrolysis and high shear from ultra-turrax stirring, which is an advantageous process for disintegrating cellulose microcrystalline and also may improve the hydrolysis process. The surface modification on the cellulose was performed by the sol-gel process, in which the sulfate groups from hydrolysis were replaced by nanoparticles of zinc oxide, which led to the increase of up to 54°C Tonset, according to thermogravimetric analysis (TGA) results. The morphology and crystallinity degree were characterized by Helium Ion Microscopy (HIM), atomic force microscopy (AFM) and X-ray diffraction. In addition, the ZnO band was observed in Fourier transform infrared spectroscopy, furthermore, the change in the zeta potential confirmed the cellulose modification. The changes in the values of proton spin-spin relaxation time for the systems showing the confined hydrogen in the rigid domains, confirmed the results observed with the aforementioned techniques, for both cellulose after hydrolysis and ZnO modified cellulose, suggesting that ZnO disrupted crystal formation in cellulose.

Sustainable preparation and characterization of thermally stable and functional cellulose nanocrystals and nanofibrils via formic acid hydrolysis

In this work,a sustainable method to prepare functional cellulose nanocrystals(CNCs)and cellulose nanofibrils(CNFs)using formic acid(FA)(a recoverable organic acid)was established.After FA hydrolysis,the obtained CNCs could be well dispersed in DMAC.Thus,the CNC products and fibrous cellulosic solid residue(FCSR)in DMAC could be easily separated by a conventional centrifugal process,and the collected FCSR could be further fibrillated to CNFs with relatively low-intensity mechanical fibrillation process.The isolated CNC products showed high crystallinity index(about 75%)and excellent thermal stability(with onset thermal degradation temperature of 325℃).Both the resultant CNCs and CNFs showed better dispersibility in DMSO,DMF and DMAC respectively because of the introduction of ester groups on the surface of the products.The presence of surface ester groups could increase the interface compatibility of nanocelluloses with polymeric matrices and enable their applications in reinforcing polymeric matrix materials(e.g.the composite films like PHVB+CNFs).

Controlled acid hydrolysis and kinetics of flavone C-glycosides from trollflowers

Acid hydrolysis mechanisms of orientin-2＂-O-galactopyranoside（OGA）,orientin and other flavone C-glycosides in the trollflowers[Trollius chinensis Bunge） were studied in this report for the first time.Hydrolysis parameters including temperature,acidity,solvent and reaction time were comprehensively investigated.OGA could be hydrolyzed to orientin,followed by an isomerization to isoorientin via a reversible Wessely-Moser rearrangement reaction under stronger acidic conditions.A first-order kinetic model fitted the hydrolysis process of OGA well.Under the optimal hydrolysis conditions of 80 ℃,1.0 mol/L H^＋ and 7 h reaction time,about 77%OGA was transformed to orientin with no detectable isoorientin.These results could be helpful for better understanding of the acid hydrolysis kinetics of flavone C-glycosides,as well as the preparation of these valuable components under controlled acid hydrolysis conditions.

Acetosolv delignification of marabou (Dichrostachys cinerea) wood with and without acid prehydrolysis

The chemical composition of marabou（Dichrostachys cinerea） wood and its treatment with acetic acid were investigated.Two different treatment approaches,direct acetosolv and combined acid prehydrolysis/acetosolv,were evaluated.The effects of acetic acid concentration（50%,70% and 90%） and temperature（normal boiling temperature and 121°C） on yield of solids,solubilization of lignin and hemicelluloses and recovery of cellulose were evaluated for both treatments.High solubilization of marabou components was observed in the direct acetosolv treatment at 121°C,especially at the highest acetic acid concentration,where around 84.8% of lignin and 78% of hemicelluloses were removed.When the material was subjected to acid prehydrolysis prior to acetosolv treatment,lignin solubilization was improved,especially at low acetic acid concentrations.Above 80% of the solubilized lignin was recovered from the liquors in the direct acetosolv treatment,but the recovery was lower in the combined treatment.Cellulose was well preserved in all the treatment schemes.

Establishment and verification of a shrinking core model for dilute acid hydrolysis of lignocellulose

The kinetics oflignocellulose hydrolysis under the conditions of high temperature and dilute acid （mass fraction 0.05%） was investigated in this paper. By studying the reducing sugar concentration versus reaction tempera ture （170℃-220℃） and reaction time （150-1800 s） during the hydrolysis process of five kinds of crop straw （rice, wheat, cotton, rape and corn）, the shrinking core model was established, and the differential equation of the model and its analytical solution were obtained. With a numerical calculation method, the kinetic equation was estimated, and the degradation of reducing sugar obeyed firstorder kinetics was obtained. The calculated results from the equations agreed well with the original experimental data. The calculation by the model showed that the reducing sugar concentration increases as the size of the particles decrease, and the uniform particles increase.

Phosphoric Acid Pretreatment and Saccharification of Paper Sludge as a Renewable Material for Cellulosic Fibers

Recycling of paper sludge waste is crucial for establishing a sustainable green industry.This waste contains valuable sugars that can be converted into important chemicals such as ethanol,poly hydroxybutyrate,and lactic acid.However,the main challenge in obtaining sugars in high yield from paper sludge is the high crystallinity of cellulose,which hinders hydrolysis.To address this,pretreatment using phosphoric acid was optimized using response surface methodology to facilitate cellulose hydrolysis with minimal energy and chemicals.The created prediction model using the response surface method considered factors such as acid concentration(ranging from 60%to 85%),consistency(ranging from 4%to 10%),temperature(ranging from 25℃to 80℃),and time(ranging from 0.5 to 4 h).The results revealed that the model’s significant factors affecting the yield were acid concentration,reaction time,temperature,and the product of acid concentration and temperature,while the model’s significant factors affecting the crystallinity were the consistency,the temperature,and their product.The results showed that the optimum conditions for pretreatment were using an acid concentration of 64%,temperature of 25℃,consistency of 10%,and time of 30 min.The hydrolysis of the conditionally pretreated paper sludge resulted in a weight loss of 42%,compared to only 18%weight loss in non-pretreated paper sludge.Furthermore,the optimized conditions led to low levels of furfurals and acetic acid,which are undesirable by-products that can interfere with sugar fermentation.The total sugar obtained under the optimized conditions was 0.43 g glucose/g sample(10.46 g/L),while the contents of methyl furfural,furfural,and acetic acid were 21.65,235.7,and 4.57 mg/L,respectively.This study demonstrates the potential of phosphoric acid for pretreatment and hydrolysis of paper sludge,enabling efficient saccharification and the production of sugars with minimal undesired by-products.

Hydrolysis of cellobiose catalyzed by zeolites—the role of acidity and micropore structure

The roles of acidity and micropore structure of zeolite were studied in the hydrolysis of the model oligosaccharide of cellulose–cellobiose. HZSM-5, HY, HMOR and Hβ zeolites were selected as model catalysts for the hydrolysis of cellobiose. The effect of acidity of zeolite, including the strength, type and location, on its catalytic activity was investigated. The strong Br？nsted acid sites located in micropores are the active sites for the hydrolysis of cellobiose to glucose. Meanwhile, the catalytic performance of zeolite is also dependent on the micropore size of zeolite.

Hydrolysis of Phosphorodithioates with a Seven-membered Ring( Ⅰ )——Kinetics and Mechanism of Acidic Hydrolysis

Introduction The phosphorodithioate is an important organophosphate pesticide. The hydrolysis reactions are very important to the metabolism of the pesticides. There have been many papers published in this domain concerning the hydrolysis of organophosphate esters. Studies on the hydrolysis of phosphorodithioate esters with a seven-membered ring, however, have rarely been reported. O, O-biphenyl S-alkyl phosphorothiolothionates with notable biological activities have recently been synthesized. In the present pater, UV spectroscopic method and molecular orbital calculation are used to carry out a research into the kinetics and-mechanisms of their hydrolyses.

Mathematical modeling for of arctigenin from acidultrasonic-assisted extractionhydrolyzed FructusArctii

A mathematical model based on Fick's first lawwas established to describe the process of ultrasonic-assisted extraction of arctigenin from acid hydrolyzed FructusArctii.Acid hydrolization with hydrochloric acid promotes the conversion of arctiin to arctigenin in the arctiin-rich active pharmaceutical ingredient, and the hydrolyzed products were further examined to investigate the process setup. By considering the mechanism of the extraction process and experimental data, the effects of parameters including solven to solid ratio, particle size of hydrolyzed samples, ethano volume fraction, ultrasound power, extraction temperature and extraction time on concentration of arctigenin were analyzed in detail. The model was suitable for simulating the process of ultrasonic-assisted extraction of arctigenin. The simulation results of the model agree well with experimental data with the deviation below13%, indicating that the mathematical mode can provide valuable guidance for the extraction of arctigenin from acid hydrolyzed FructusArctii.

Partial Hydrolysis of the Fucosylated Chondroitin Sulfate from Sea Cucumber Isostichopus badionotus and Its Mechanism

The method for preparing low molecular weight fucosylated chondroitin sulfate from sea cucumber lsostichopus badionotus using partial acid hydrolysis was reported, and its hydrolysis mechanism was also investigated. The sea cucumber chondroitin sulfate FCS was hydrolyzed under different conditions （80℃3 h and 6 h）, then isolated and purified on a Bio-P-4 geltration to prepare low molecular weight fractions （LMWF-FCS）. The chemical compositions of LMWF-FCS showed the branched fucose （Fuc） was cleaved during acid hydrolysis process, whereas the mole ratio of acetyl-galactosamine （GalNAc） and glucuronic acid （GlcA） in the backbone remained the same, which indicated the backbone was a typical chondroitin sulfate structure. The disaccharide composition analysis of LMWF-FCS suggested that the sulfation patterns of GalNAc in the backbone chain changed and the substitution value was reduced. Furthermore, the 1D NMR analysis illustrated the branched-Fuc was cleaved during acid hydrolysis, but their substitution patterns were not influenced, which was distinct from the previous reports that the substitutions of branched-Fuc in FCS were easy to change. Simultaneously, the sulfation pattern of GalNAc in backbone chain changed obviously in the acid hydrolysis process. The anticoagulant activity in vitro illuminated the anticoagulant activity of the degradation products over time in the acid hydrolysis are gradually declined, but still kept good. Therefore, the LMWF-FCS prepared could be developed as a new anticoagulant and antithrombotic drug like low molecular weight heparin.

Hydrolysis of soy isoflavone conjugates using enzyme may underestimate isoflavone concentrations in tissue

Objective:To investigate the differences of using enzymatic hydrolysis and acid hydrolysis for identification and quantification of isoflavone aglycones from biomatrices.Methods:β-glucuronidase/sulfatase isolated from Helix pomatia for routine enzymatic hydrolysis or 6N HCl was used to release glucuronide and sulfate conjugates in the serum,urine and tissue samples.Profiles of soy isoflavones after enzymatic hydrolysis or acid hydrolysis in several tissues of rat fed with diets containing soy protein isolate were also compared using LC/MS and HPLC-ECD.Results:Acid hydrolysis released more aglycone than enzymatic digestion(P<0.05)in liver tissue.The total genistein,daidzein and other metabolites were 20%to 60%lower in samples from enzymatic hydrolysis than in acid hydrolysis.Conclusion:These results indicated that unknown factors in tissues reduced the enzymatic hydrolytic efficiency for releasing isoflavone aglycones even in optimized condition.This would underestimate isoflavone tissue concentrations up to 60%.

Effect of Acid Treatment on the Saccharification of Wheat Bran Cellulose

[ Objective] The aim was to improve the saccharification of wheat bran cellulose. [ Method] Taking the wheat bran as raw materials, and using orthogonal method, the effects of acid concentration, temperature, times and substrate concentration on the saccharification were investigated. [ Result] The influence of temperature on the acid treatment of the sacchadfication of wheat bran cellulose was significant. Influences of acid concentration on the hydrolysis were distinct. Influences of time and substrate concentration were insignificant. The optimal pretreatment conditions were 1.5% of sulfuric acid concentration and 0. 067 g/ml of substrate concentration at 100℃ in three hours. Under this condition, the sugar concentration was 38.137 mg/ml, and the hydrolysis rate reached 51.485%. [ Conclusion] The study improved the saccharification of wheat bran cellulose, which provided theoretical basis for the application of wheat bran industrial process.

Modeling of degradation kinetics of Salvianolic acid B at different temperatures and pH values

In this work,the effects of degradation time,temperature,and pH value on the degradation of Salvianolic acid B in aqueous solution were determined.Higher pH values,higher extraction temperature,and longer extraction time led to more degradation of Salvianolic acid B.Danshensu concentration increased as Salvianolic acid B degraded.A mechanism model was developed considering the degradation of Salvianolic acid E and lithospermic acid,which were two degradation products of Salvianolic acid B.The reverse reactions of Salvianolic acid B degradation were also considered.Degradation kinetic constants were calibrated.The degradation kinetics of Salvianolic acid B,lithospermic acid,and Danshensu in a Salvia miltiorrhiza extract aqueous solution were predicted using the mechanism model.The predicted concentrations agreed well with the experimental results.This model was developed using degradation data obtained from simple composition systems,but it can be applied in a complex botanical mixture with high prediction accuracy.

Conversion of Sugarcane Shoots and Leaves into Reducing Sugars by Pretreatment and Enzymatic Hydrolysis

Sugarcane shoots and leaves consist of 38% cellulose, 30.6% hemicellulose and 12.8% lignin on dry solid （DS） basis and have the potential to serve as low cost feedstocks for ethanol production. The pretreatment and enzymatic hydrolysis conditions include particle size, alkali （NaOH）/dilute acid （H2SO4） pretreatment, chemical and substrate concentrations, temperature, autoclaving time for pretreatment, enzyme concentration, pH and temperature for hydrolysis varied were evaluated for conversion of sugarcane shoots and leaves cellulose and hemicellulose to reducing sugar. The optimum conditions were accomplished by using 14% w/v DS of 0-10 mm sugarcane shoots and leaves in particle size, pretreated with 1.5% w/v of dilute sulfuric acid at 121℃, 15 lbs/in2 for 15 min and enzymatic saccharification using 40 FPU/g DS cellulose at 50℃ and pH 5, After incubating at 160 rpm for 12 hrs, 59 g/L or 386,38 mg/g DS of reducing sugar and 50.69% saccharification were obtained.