Effect of pH and pH-Shifting on Lignin–Protein Interaction and Properties of Lignin-Protein Polymers.

Autor: Pradyawong, Sarocha1 (AUTHOR), Shrestha, Ruben2 (AUTHOR), Li, Ping2 (AUTHOR), Sun, Xiuzhi Susan3 (AUTHOR), Wang, Donghai1 (AUTHOR) dwang@ksu.edu
Předmět:
Zdroj: Journal of Polymers & the Environment. May2022, Vol. 30 Issue 5, p1908-1919. 12p.
Abstrakt: Innovation of high-value added lignin derivatives has become a topic of interest, but lignin modification and utilization remain a challenge due to lignin's complicated structure. In our previous study, we successfully improved water resistance and adhesion performance of soy protein adhesives using unmodified lignin. This study focuses on lignin modification as well as lignin-protein properties and interactions. Lignin modification was achieved by pH changes and pH-shifting. Cleavage of β-O-4 linkage was observed at pH 8.5 and pH 12, resulting in smaller particle sizes and changes in thermal properties. Partial repolymerization was found after pH-shifting treatments. Lignin increased the strength of protein films under high temperature and significantly enhanced the water resistance of soy protein at pH 12. Cross-linking of protein and lignin took place via carbonyl, amino, and hydroxyl groups. Multiple-point interactions between lignin and protein resulted in a stronger lignin-protein network. Additional lignin-protein complexes with high molecular weight were detected with an elevated lignin concentration at pH 8.5. The binding interaction between lignin and protein, although of non-specific nature, was also observed by isothermal titration calorimetry (ITC). Findings of this study contribute to the further development of green lignin-protein products. [ABSTRACT FROM AUTHOR]
Databáze: GreenFILE