Co-reporter:Wen Jiang, Yang Yang, Renyou Tao, Xiaoqin Jiang, Xiaohua Zhou, Zhiming Zhou
Carbohydrate Polymers 2017 Volume 176(Volume 176) pp:
Publication Date(Web):15 November 2017
DOI:10.1016/j.carbpol.2017.08.067
•Rice protein was successively hydrolyzed by 3 types of proteases.•A novel chitosan-based biosorbent was prepared.•PMCCR showed efficient adsorption property to aromatic amino acids.•Rice protein enzymatic hydrolysates with Fischer’s ratio higher than 20 was prepared.Rice protein was successively hydrolyzed by rice protein hydrolysis special enzyme, chymotrypsin and carboxypeptidases A. Then a novel chitosan-based biosorbent cross-linked with phenethylamine (PMCCR) was synthesized and firstly used for adsorption of aromatic amino acids (AAA) from rice protein enzymatic hydrolysates (RPEH). The characterizations of PMCCR indicated that phenethylamine was successfully cross-linked with chitosan, and the particle size of PMCCR was 500–1000 μm with pore diameter of 50–100 μm. Furthermore, PMCCR showed an efficient adsorption property to AAA in RPEH, reaching equilibrium at 80 min of 28.54 mg/g, and the adsorption data could be well fitted with Freundlich isotherm model. The amino acids analysis of RPEH after adsorption (RPEHA) showed that AAA in RPEH was basically adsorbed by PMCCR, with a Fisher’s ratio of 21.2. Overall, this novel chitosan-based biosorbent cross-linked with phenethylamine might be highly promising to facilitate efficient adsorption of aromatic amino acids and prepare protein enzymatic hydrolysates with a high Fischer’s ratio.
Co-reporter:Chunhua Zhao;Yan Xiao;Dan Wang;Zhen Zhou;Zhixiong Yang;Xiaoqin Jiang;Jiang Wang
Journal of Chemical Technology and Biotechnology 2016 Volume 91( Issue 7) pp:2047-2055
Publication Date(Web):
DOI:10.1002/jctb.4799
Abstract
BACKGOUND
Currently, the dominant theories on extraction mechanisms of amino acids are mainly deduced from mathematical models or reaction equations, it is thus necessary to obtain direct evidence for the extraction mechanisms by experimental methods. This work aims to reveal the mechanisms of L-lysine (L-Lys) extraction with sec-octylphenoxy acetic acid (CA-12) in sulfonated kerosene by atomic force microscopy (AFM), half-saturated fluorometric experiment and competition experiment.
RESULTS
The ionic bond based on the electrostatic attraction between the amino group of L-Lys and the carboxyl group of CA-12 was verified visually by high-resolution AFM. Half of the amino groups of L-Lys were labeled by o-phthalaldehyde (OPA) to form half-saturated fluorescent derivatives which were then extracted by means of CA-12 in sulfonated kerosene. The electrostatic attraction between the free amino group of L-Lys and the carboxyl group of CA-12 was illustrated by the relationships between OPA dosage and fluorescence intensities of stock solution and extracted liquid. This electrostatic interaction was also demonstrated by the competition experiment using three other amino acids including L-arginine, L-aspartic acid and L-alanine as competitive reagents.
CONCLUSION
The chemical force of L-Lys extraction with CA-12 in sulfonated kerosene was comprehensively demonstrated to be the electrostatic interaction between the amino group and the carboxyl group. © 2015 Society of Chemical Industry
