Base-catalyzed Degradations of Carbohydrates. IX. β-Eliminations of 4-O-Substituted Hexopyranosiduronates

1975 ◽  
Vol 53 (14) ◽  
pp. 2182-2188 ◽  
Author(s):  
Gerald O. Aspinall ◽  
Thinnayam N. Krishnamurthy ◽  
Walter Mitura ◽  
Masuo Funabashi
Keyword(s):  
Acid Hydrolysis ◽  
Reducing Sugars ◽  
Model Compounds ◽  
Methyl Methyl ◽  
Hydrolysis Of

Two methylated disaccharides, methyl [methyl 4-O-(2,3,4,6-tetra-O-methyl-α-D-glucopyranosyl)-2,3-di-O-methyl-β-D-glucopyranosid]uronate (9) and methyl 6-O-(methyl 2,3,4-tri-O-methyl-α-D-galactopyranosyluronate)-2,3,4-tri-O-methyl-β-D-glucopyranoside (15) have been synthesized and used as model compounds for the study of the base-catalyzed β-elimination of 4-O-substituted hexopyranosiduronates without degradation of exposed reducing sugars and of the selective acid hydrolysis of hex-4-enopyranosiduronates.

scholarly journals Acid Hydrolysis of Lignocellulosic Materials for The Production of Second Generation Ethanol

2021 ◽  
Author(s):  
Mariane Daniella Silva ◽  
João Pedro Cano ◽  
Fernanda Maria Pagane Guereschi Ernandes ◽  
Crispin Humberto Garcia-Cruz
Keyword(s):  
Acid Hydrolysis ◽  
Agricultural Production ◽  
Fossil Fuels ◽  
Second Generation ◽  
Reducing Sugars ◽  
Lignocellulosic Materials ◽  
Sugar Release ◽  
Different Types ◽  
Hydrolysis Of ◽  
Second Generation Ethanol

Abstract Brazil is one of the countries with the largest agricultural production in the world. Therefore, it is capable of generating large amounts of agro-industrial waste that can be used as biomass for the production of biofuels. Second generation ethanol is a renewable energy alternative, capable of replacing fossil fuels. Within this context, the objective of the present work was to study the effect of diluted acid hydrolysis in different types of lignocellulosic residues and the consequent production of 2G ethanol from these hydrolysates using different fermenting microorganisms. The acid concentration that released the highest content of fermentable sugars from the acid hydrolysis of lignocellulosic materials was 5.0% of sulfuric acid and the contact time with the biomass was 15 min. while heating in autoclave. The material that showed the highest sugar release after acid hydrolysis was cassava residues, with 131.09 g.L− 1 of reducing sugars. The fermentations were carried out with microorganisms alone and also in consortium. The largest production of 2G ethanol was from the hydrolyzate of soybean hulls, of 47.70 g.L− 1 of ethanol by the consortium of Zymomonasmobilis and Candida tropicalis, during 8 h of fermentation and showed productivity of 5.96 g.L− 1.h− 1.

Investigation on Acid Hydrolysis of Inulin: A Response Surface Methodology Approach

2009 ◽  
Vol 5 (3) ◽  
Author(s):  
Ebrahim Eskandari Nasab ◽  
Mehran Habibi-Rezaei ◽  
Afshin Khaki ◽  
Mohammad Balvardi
Keyword(s):  
Response Surface Methodology ◽  
Acid Hydrolysis ◽  
Response Surface ◽  
Reducing Sugars ◽  
Experimental Program ◽  
Central Composite Rotatable Design ◽  
Alkaline Ph ◽  
Inulin Hydrolysis ◽  
Hydrolysis Of ◽  
Central Composite

In this study, the acid hydrolysis of inulin was investigated as a function of three variables: pH, temperature and time. Inulin hydrolysis was detected by measurement of reducing sugars, using Dinitro Salicylic acid (DNS) method. The central composite rotatable design (CCRD) was applied to design an experimental program to model the effects of acidic and alkaline pH on the inulin hydrolysis. Additionally, response surface methodology (RSM) was utilized for data analysis. The statistical analysis of the results confirmed that pH, temperature and time are significant variables at acidic pH, whereas at alkaline pH, these variables are insignificant. The maximum amount of inulin hydrolysis obtained at the pH < 2, temperature > 90°C and the time of 1 hrs.

scholarly journals Semidry acid hydrolysis of cellulose sustained by autoclaving for production of reducing sugars for bacterial biohydrogen generation from various cellulose feedstock

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11244
Author(s):  
Fatthy Mohamed Morsy ◽  
Medhat Elbadry ◽  
Yasser Elbahloul
Keyword(s):  
Acid Hydrolysis ◽  
Reducing Sugars ◽  
Gas Production ◽  
Hydrogen Gas ◽  
Biohydrogen Production ◽  
Hydrogen Yield ◽  
E Coli ◽  
Dry Biomass ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

Cellulosic biowastes are one of the cheapest and most abundant renewable organic materials on earth that can be, subsequent to hydrolysis, utilized as an organic carbon source for several fermentation biotechnologies. This study was devoted to explore a semidry acid hydrolysis of cellulose for decreasing the cost and ionic strength of the hydrolysate. For semidry acid hydrolysis, cellulose was just wetted with HCl (0 to 7 M) and subjected to autoclaving. The optimum molar concentration of HCl and period of autoclaving for semidry acid hydrolysis of cellulose were 6 M and 50 min respectively. Subsequent to the semidry acid hydrolysis with a minimum volume of 6 M HCl sustained by autoclaving, the hydrolysate was diluted with distilled water and neutralized with NaOH (0.5 M). The reducing sugars produced from the semidry acid hydrolysis of cellulose was further used for dark fermentation biohydrogen production by Escherichia coli as a representative of most hydrogen producing eubacteria which cannot utilize non-hydrolyzed cellulose. An isolated E. coli TFYM was used where this bacterium was morphologically and biochemically characterized and further identified by phylogenetic 16S rRNA encoding gene sequence analysis. The reducing sugars produced by semidry acid hydrolysis could be efficiently utilized by E. coli producing 0.4 mol H2 mol−1 hexose with a maximum rate of hydrogen gas production of 23.3 ml H2 h−1 L−1 and an estimated hydrogen yield of 20.5 (L H2 kg−1 dry biomass). The cheap cellulosic biowastes of wheat bran, sawdust and sugarcane bagasse could be hydrolyzed by semidry acid hydrolysis where the estimated hydrogen yield per kg of its dry biomass were 36, 18 and 32 (L H2 kg−1 dry biomass) respectively indicating a good feasibility of hydrogen production from reducing sugars prepared by semidry acid hydrolysis of these cellulosic biowastes. Semidry acid hydrolysis could also be effectively used for hydrolyzing non-cellulosic polysaccharides of dry cyanobacterial biomass. The described semidry acid hydrolysis of cellulosic biowastes in this study might be applicable not only for bacterial biohydrogen production but also for various hydrolyzed cellulose-based fermentation biotechnologies.

Acid hydrolysis of damaged wheat grains: Modeling the formation of reducing sugars by a neural network approach

2020 ◽  
Vol 149 ◽  
pp. 112351 ◽  
Author(s):  
Ranjna Sirohi ◽  
Jai Prakash Pandey ◽  
Anupama Singh ◽  
Raveendran Sindhu ◽  
Umesh Chandra Lohani ◽  
...  
Keyword(s):  
Neural Network ◽  
Acid Hydrolysis ◽  
Reducing Sugars ◽  
Network Approach ◽  
Neural Network Approach ◽  
Wheat Grains ◽  
Hydrolysis Of

scholarly journals Identification And Quantification Of Hydrocarbons Produced From The Acid-Pretreated Kitchen Waste By Using Fungal And Bacterial Strains

2021 ◽  
Author(s):  
Nayab Zahara ◽  
Muhammad Irfan Jalees ◽  
Muhammad Umar Farooq ◽  
Arfa Iqbal ◽  
Sadaan Umais Malik
Keyword(s):  
Escherichia Coli ◽  
Aspergillus Niger ◽  
Acid Hydrolysis ◽  
Reducing Sugars ◽  
Dilute Acid ◽  
Bacterial Strains ◽  
Kitchen Waste ◽  
Dilute Acid Hydrolysis ◽  
Fermented Product ◽  
Hydrolysis Of

Abstract This study was conducted to identify and quantify hydrocarbons produced during bio-fuel production using kitchen waste (KW). KW is a complex mixture of hardly digestible compounds, mainly lignin, cellulose and hemicellulose, and easily digestible compounds, mostly starchy materials. Therefore, KW has a high potential for the production of biofuel after the chemical hydrolysis of lignocellulose, starch and carbohydrates. In this study, after the physically pretreatment (dried and crushed) of KW, dilute-acid hydrolysis was used for the hydrolysis of lignocellulose and starchy materials, eliminating the enzymes requirement. The dilute acid hydrolysis was conducted with 1, 3 and 5% (w/w) sulfuric acid at 90 and 120°C for 30, 60, 90 and 120 min. The hydrolysis with 5% acid at 120°C for 120 min resulted in the hydrolysate with the highest reducing sugar concentration of 97.917 ± 0.5 g/kg and Energy of 1.567 ± 0.008 MJ/kg. The reducing sugars were used as substrate in fermentation by fungal strain Aspergillus niger, bacterial strains Lacto-bacillus and Escherichia coli, to produce hydrocarbons. The fermented product was quantified after every day till the fermentation time is over i.e. no more products were formed. Biofuel production from Aspergillus niger, Escherichia coli and Lacto-bacillus was 64%, 45% and 50% after 72 hr. Fermented product contains mainly hydrocarbons as identified by GC-MS analysis. Calorific value of sample and biofuel determined on Differential Scanning Calorimetry were 0.6MJ kg− 1 for sample before fermentation and 3.56 MJ kg− 1, 3.33 MJ kg− 1 and 2.67 MJ kg− 1 for KW fermented by Aspergillus niger, Escherichia coli and Lacto-bacillus, respectively. Hence, maximum of 64% reducing sugars were converted into hydrocarbons (biofuel) after fermentation by Aspergillus niger.

scholarly journals Acid and enzymatic hydrolysis to recover reducing sugars from cassava bagasse: an economic study

2002 ◽  
Vol 45 (3) ◽  
pp. 393-400 ◽  
Author(s):  
Adenise Lorenci Woiciechowski ◽  
Saul Nitsche ◽  
Ashok Pandey ◽  
Carlos Ricardo Soccol
Keyword(s):  
Enzymatic Hydrolysis ◽  
Acid Hydrolysis ◽  
Reducing Sugars ◽  
Economic Study ◽  
Process Economics ◽  
Operational Costs ◽  
Cassava Bagasse ◽  
Cylindrical Reactor ◽  
Statistical Program ◽  
Hydrolysis Of

The objective of this work was to study the acid and enzymatic hydrolysis of cassava bagasse for the recovery of reducing sugars and to establish the operational costs. A statistical program "Statistica", based on the surface response was used to optimize the recovery of reducing sugars in both the processes. The process economics was determined considering the values of reducing sugars obtained at laboratory scale, and the operations costs of a cylindrical reactor of 1500 L, with flat walls at the top and bottom. The reactor was operated with 150 kg of cassava bagasse and 1350 kg of water. The yield of the acid hydrolysis was 62.4 g of reducing sugars from 100 g of cassava bagasse containing 66% starch. It represented 94.5% of reducing sugar recovery. The yield of the enzymatic hydrolysis was 77.1 g of reducing sugars from 120 g of cassava bagasse, which represented 97.3% of reducing sugars recovery. Concerning to the time, a batch of acid hydrolysis required 10 minutes, plus the time to heat and cool the reactor, and a batch of the enzymatic hydrolysis needed 25 hours and 20 minutes, plus the time to heat and to cool the reactor. Thus, the acid hydrolysis of 150 kg of cassava bagasse required US$ 34.27, and the enzymatic hydrolysis of the same amount of cassava bagasse required US$ 2470.99.

DETERMINATION OF MICRO-AMOUNTS OF 5β-PREGNAN-3α-OL-20-ONE IN URINE USING INFRARED-SPECTROMETRY

1962 ◽  
Vol 41 (2) ◽  
pp. 234-246 ◽  
Author(s):  
H. J. van der Molen
Keyword(s):  
Infrared Spectrum ◽  
Quantitative Determination ◽  
Acid Hydrolysis ◽  
Chromatographic Separation ◽  
Pure Form ◽  
Infrared Spectrometry ◽  
Hydrolysis Of

ABSTRACT A procedure for the quantitative determination of 5β-pregnan-3α-ol-20-one in urine is described. After acid hydrolysis of the pregnanolone-conjugates in urine, the free steroids are extracted with toluene. Pregnanolone is isolated in a pure form as its acetate; after chromatographic separation of the free steroids on alumina, the fraction containing pregnanolone is acetylated and rechromatographed on alumina. Quantitative determination of the isolated pregnanolone-acetate is carried out with the aid of the infrared spectrum recorded by a micro KBr-wafermethod. The reliability of the method under various conditions is discussed under the headings, specificity, accuracy, precision and sensitivity. It is possible to determine 30–40 μg pregnanolone in a 24-hours urine portion with a precision of 25%.

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