scholarly journals Application of Environment-Friendly Solid Supported Acid Catalyst for Hydrolysis of Jaggery

2020 ◽  
Vol 5 (1) ◽  
Keyword(s):  
Acid Catalyst ◽  
Environment Friendly ◽  
Hydrolysis Of

scholarly journals Pseudomonas putida MPE, a manganese-dependent endonuclease of the binuclear metallophosphoesterase superfamily, incises single-strand DNA in two orientations to yield a mixture of 3′-PO4 and 3′-OH termini

2020 ◽  
Author(s):  
Shreya Ghosh ◽  
Anam Ejaz ◽  
Lucas Repeta ◽  
Stewart Shuman
Keyword(s):  
Pseudomonas Putida ◽  
Bound Water ◽  
Acid Catalyst ◽  
Nuclease Activity ◽  
Single Strand ◽  
Dna Endonuclease ◽  
Dependent Endonuclease ◽  
Leaving Group ◽  
Phosphodiester Hydrolysis ◽  
Hydrolysis Of

Abstract Pseudomonas putida MPE exemplifies a novel clade of manganese-dependent single-strand DNA endonuclease within the binuclear metallophosphoesterase superfamily. MPE is encoded within a widely conserved DNA repair operon. Via structure-guided mutagenesis, we identify His113 and His81 as essential for DNA nuclease activity, albeit inessential for hydrolysis of bis-p-nitrophenylphosphate. We propose that His113 contacts the scissile phosphodiester and serves as a general acid catalyst to expel the OH leaving group of the product strand. We find that MPE cleaves the 3′ and 5′ single-strands of tailed duplex DNAs and that MPE can sense and incise duplexes at sites of short mismatch bulges and opposite a nick. We show that MPE is an ambidextrous phosphodiesterase capable of hydrolyzing the ssDNA backbone in either orientation to generate a mixture of 3′-OH and 3′-PO4 cleavage products. The directionality of phosphodiester hydrolysis is dictated by the orientation of the water nucleophile vis-à-vis the OH leaving group, which must be near apical for the reaction to proceed. We propose that the MPE active site and metal-bound water nucleophile are invariant and the enzyme can bind the ssDNA productively in opposite orientations.

The Effect of Dicarboxylic Acid Catalyst Structure on Hydrolysis of Cellulose Model Compound D-Cellobiose in Water

2021 ◽  
Vol 08 ◽  
Author(s):  
Harshica Fernando ◽  
Ananda S. Amarasekara
Keyword(s):  
Dicarboxylic Acid ◽  
Model Compound ◽  
Acid Catalyst ◽  
Catalytic Activities ◽  
Polycarboxylic Acids ◽  
Hydrolysis Of Cellulose ◽  
Phthalic Acids ◽  
Turn Over Frequency ◽  
Turn Over ◽  
Hydrolysis Of

Background: Polycarboxylic acids are of interest as simple mimics for cellulase enzyme catalyzed depolymerization of cellulose. In this study, DFT calculations were used to investigate the effect of structure on dicarboxylic acid organo-catalyzed hydrolysis of cellulose model compound D-cellobiose to D-glucose. Methods: Binding energy of the complex formed between D-cellobiose and acid (Ebind), as well as glycosidic oxygen to dicarboxylic acid closest acidic H distance were studied as key parameters affecting the turn over frequency of hydrolysis in water. Result: α-D-cellobiose - dicarboxylic acid catalyst down face approach showed high Ebind values for five of the six acids studied; indicating the favorability of down face approach. Maleic, cis-1,2-cyclohexane dicarboxylic, and phthalic acids with the highest catalytic activities showed glycosidic oxygen to dicarboxylic acid acidic H distances 3.5-3.6 Å in the preferred configuration. Conclusion: The high catalytic activities of these acids may be due to the rigid structure, where acid groups are held in a fixed geometry.

scholarly journals Combination of Autohydrolysis and Catalytic Hydrolysis of Biomass for the Production of Hemicellulose Oligosaccharides and Sugars

Reactions ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 30-46
Author(s):  
Léa Vilcocq ◽  
Agnès Crepet ◽  
Patrick Jame ◽  
Florbela Carvalheiro ◽  
Luis C. Duarte
Keyword(s):  
Agricultural Waste ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Energy Crop ◽  
Catalytic Hydrolysis ◽  
Experimental Conditions ◽  
Different Types ◽  
Hemicellulosic Sugars ◽  
Hydrolysis Of

Three different types of biomass sourced from forestry waste (eucalyptus residues), agricultural waste (wheat straw), and energy crop (miscanthus) were used as starting materials to produce hemicellulosic sugars, furans (furfural and hydroxymethylfurfural), and oligosaccharides. A two-step hybrid process was implemented; biomass was first autohydrolysed without any additive to extract hemicelluloses and dissolve it in water. Then, the hydrolysate was treated with a solid acid catalyst, TiO2-WOx, in order to achieve hydrolysis and produce monomeric sugars and furans. This article investigates the role of the biomass type, autohydrolysis experimental conditions, polymerisation degree and composition of hemicelluloses on the performance of the process coupling autohydrolysis and catalytic hydrolysis. The highest global yields of both oligosaccharides and monomeric sugars were obtained from Eucalyptus (37% and 18%, respectively).

scholarly journals Efficient Production of Acetic Acid from Nipa (Nypa fruticans) Sap by Moorella thermoacetica (f. Clostridium thermoaceticum)

2019 ◽  
Author(s):  
Dung Van Nguyen ◽  
Pinthep Sethapokin ◽  
Harifara Rabemanolontsoa ◽  
Eiji Minami ◽  
Haruo Kawamoto ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Oxalic Acid ◽  
Acid Catalyst ◽  
Cost Effective ◽  
Efficient Production ◽  
Acid Fermentation ◽  
Acid Yield ◽  
Moorella Thermoacetica ◽  
Nypa Fruticans ◽  
Hydrolysis Of

To valorize the underutilized nipa sap composed mainly of sucrose, glucose and fructose, acetic acid fermentation by Moorella thermoacetica was explored. Given that M. thermoacetica cannot directly metabolize sucrose, we evaluated various catalysts for the hydrolysis of this material. Oxalic acid and invertase exhibited high levels of activity towards the hydrolysis of the sucrose in nipa sap to glucose and fructose. Although these two methods consumed similar levels of energy for the hydrolysis of sucrose, oxalic acid was found to be more cost-effective. Nipa saps hydrolyzed by these two catalysts were also fermented by M. thermoacetica. The results revealed that the two hydrolyzed sap mixtures gave 10.0 g/L of acetic acid from the 10.2 g/L of substrate sugars in nipa sap. Notably, the results showed that the oxalic acid catalyst was also fermented to acetic acid, which avoided the need to remove the catalyst from the product stream. Taken together, these results show that oxalic acid hydrolysis is superior to enzymatic hydrolysis for the pretreatment of nipa sap. The acetic acid yield achieved in this study corresponds to a conversion efficiency of 98%, which is about 3.6 times higher than that achieved using the traditional methods. The process developed in this study therefore has high potential as a green biorefinery process for the efficient conversion of sucrose-containing nipa sap to bio-derived acetic acid.

Hydrolysis of lignocellulosic biomass using silica based separable solid acid catalyst

2019 ◽  
Vol 29 (1) ◽  
pp. 41-47
Author(s):  
Jong-Hwa Kim ◽  
Jong-Chan Kim ◽  
Da-Song Lee ◽  
Hanseob Jeong ◽  
Soo Min Lee ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Solid Acid ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Hydrolysis Of

A self-confinement synthesis of a POM-decorated MOF thin film for actively hydrolyzing ethyl acetate

2020 ◽  
Vol 56 (89) ◽  
pp. 13840-13843
Author(s):  
Zhou Fang ◽  
Danke Chen ◽  
Zhuoyi Li ◽  
Xu Ma ◽  
Xinyi Wan ◽  
...  
Keyword(s):  
Thin Film ◽  
Ethyl Acetate ◽  
Solid Acid ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

A solid acid catalyst POM@MOF thin film was prepared and utilized for the efficient hydrolysis of esters with a long durability.

Hydrolysis of Cellulose by a Solid Acid Catalyst under Optimal Reaction Conditions

2009 ◽  
Vol 113 (8) ◽  
pp. 3181-3188 ◽  
Author(s):  
Daizo Yamaguchi ◽  
Masaaki Kitano ◽  
Satoshi Suganuma ◽  
Kiyotaka Nakajima ◽  
Hideki Kato ◽  
...  
Keyword(s):  
Solid Acid ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Reaction Conditions ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of ◽  
Optimal Reaction

FeCl3–SiO2 as heterogeneous catalysts for the preparation of dihydropyrano[3,2-b]chromenediones

2011 ◽  
Vol 76 (12) ◽  
pp. 1791-1797 ◽  
Author(s):  
Wei-Lin Li ◽  
Jin-Ying Liang ◽  
Tian-Bao Wang ◽  
Ya-Qin Yang
Keyword(s):  
Heterogeneous Catalyst ◽  
Heterogeneous Catalysts ◽  
Solid Acid ◽  
Kojic Acid ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Environment Friendly ◽  
Appreciable Change

FeCl3–SiO2 is environment-friendly heterogeneous catalyst for the condensation of kojic acid and aldehydes with dimedone to afford dihydropyrano[3,2-b]chromenediones. The solid acid catalyst is stable and can be easily recovered and reused without appreciable change in its efficiency.

Sign in / Sign up

Export Citation Format

Share Document