The reaction process and corresponding mechanism of coagulation and gelation of native soy protein isolates (SPIs) induced by microbial transglutaminase (MTGase) were investigated. The protein constituents of SPIs, including a majority of subunits of β‐conglycinin and acidic subunits of glycinin, could be polymerized by MTGase to form high weight molecular (WM) biopolymers. Both the coagulation and gelation reactions of native SPI solutions induced by MTGase were dependent upon the initial protein substrate concentration ([C] 0 ). In the coagulating reactions, the turbidity of SPI solutions continually increased with increasing [C] 0 in the range from 0.25 to 3.0%. As for the gelation reactions, with the concentration increasing from 3 to 8% (w/v), the onset time of gelation of native SPIs induced by 0.8 units/mL of MTGase at 37C shortened by ∼5‐fold, and the storage modulus (G′) of finally formed gels (after 4 h) increased from ∼1 to 1300 Pa. Both the coagulation and gelation reactions of SPI solutions were promoted remarkably by increasing the enzyme concentration. Sodium Dodecyl Sulfate‐Polyacrylamide Gel Electrophoresis analysis showed that the protein constituents of MTGase‐induced aggregates of SPI (2% w/v) were mainly composed of basic subunits of glycinin and some of newly cross‐linked high MW biopolymers. The solubility analysis of protein constituents indicated that the covalent cross‐linkage, hydrophobic and H bindings and disulfide bonds were mainly involved in the coagulation of SPI induced by MTGase.
The mixture of ionic liquid (IL) and aqueous ethanol has been proven to be a promising biomass pretreatment solvent, facilitating the separation of cellulose and faster breakdown of hemicellulose through the disruption of lignin. However, lignin and sugar monomers from the hydrolysis of polysaccharides are soluble in IL and difficult to separate. This complicates the recycling of IL. To address this, CrCl3 and CrCl3·6H2O are used as catalysts for the one-pot conversion of lignin and sugars in the ionic liquid 1-butyl-3-methyl imidazolium chloride ([BMIM]Cl). Furfural resin or humin is produced and separated from IL after the reactions. When catalyzed by CrCl3.6H2O and at a high temperature (≥170 °C), almost all the lignin and sugars are transformed to humin, which leads to the high efficiency of IL recycling. And the mechanisms of the reactions are studied with guaiacylglycerol-beta-guaiacyl ether (GG) and glucose as model compounds.
A new method for selective separation of wood components is presented. Based on Hansen's theory of solubility, ionic liquid (IL) 1-butyl-3-methylimidazolium bromine ([Bmin]Br) was mixed with aqueous ethanol. HBr the acid catalyst in the degradation of wood components, was found to form in situ by ion exchange between IL and organic acid. The hydrogen bonding capacity of the mixture was enhanced as the presence of IL, which led to the promotion of the solubilization of lignin and other products from carbohydrates hydrolysis. The data showed that, variations of the IL concentration caused cellulose to be separated from pine wood with a purity of more than 94%, or to be hydrolyzed and converted into saccharides together with hemicellulose. Because of the complete hydrolysis of hemicellulose, the cross-linked matrix of lignin and hemicellulose was destroyed, which led to the isolation of lignin with a high purity of about 93%.
The mixture of aqueous ethanol and ionic liquid (IL) 1-butyl-3-methylimidazolium bromine ([Bmin]Br) was used to treat woody biomass, and different analysis methods such as I H-NMR, GC-MS, HPAEC, and FTIR were used to determine the efficiency of separation and the products. It is shown that macromolecules of lignin were degraded and dissolved into the solvent mixture, and were separated by adding anti-solvent into the solution. The presence of ionic liquid enhanced the hydrogen bonding capacity of the solvent, and hindered the adsorbing of lignin micro-molecules by cellulose, which resulted in the cellulose being separated as solid residue with high purity (2:94%). Therefore, the mixture of aqueous ethanol and IL offers a novel method for wood separation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.