On the Surface Interactions of Proteins with Lignin

Carlos Salas, Orlando J. Rojas*, Lucian A. Lucia, Martin A. Hubbe, Jan Genzer

*Corresponding author for this work

    Research output: Contribution to journalArticleScientificpeer-review

    45 Citations (Scopus)

    Abstract

    Lignins are used often in formulations involving proteins but little is known about the surface interactions between these important biomacromolecules. In this work, we investigate the interactions at the solid-liquid interface of lignin with the two main proteins in soy, glycinin (11S) and beta-conglycinin (7S). The extent of adsorption of 11S and 7S onto lignin films and the degree of hydration of the interfacial layers is quantified via Quartz crystal microgravimetry (QCM) and surface plasmon resonance (SPR). Solution ionic strength and protein denaturation (2-mercaptoethanol and urea) critically affect the adsorption process as protein molecules undergo conformational changes and their hydrophobic or hydrophilic amino acid residues interact with the surrounding medium. In general, the adsorption of the undenatured proteins onto lignin is more extensive compared to that of the denatured biomolecules and a large amount of water is coupled to the adsorbed molecules. The reduction in water contact angle after protein adsorption (by similar to 40 degrees and 35 degrees for undenatured 11S and 7S, respectively) is explained by strong nonspecific interactions between soy proteins and lignin.

    Original languageEnglish
    Pages (from-to)199-206
    Number of pages8
    JournalACS Applied Materials and Interfaces
    Volume5
    Issue number1
    DOIs
    Publication statusPublished - 9 Jan 2013
    MoE publication typeA1 Journal article-refereed

    Keywords

    • adsorption
    • lignin
    • proteins
    • soy glycinin
    • beta-conglycinin
    • quartz crystal microbalance
    • QUARTZ-CRYSTAL MICROBALANCE
    • SMOOTH MODEL SURFACES
    • SOYBEAN 11S GLOBULIN
    • BETA-CONGLYCININ
    • SOY PROTEINS
    • VISCOELASTIC PROPERTIES
    • FUNCTIONAL-PROPERTIES
    • PLASMON RESONANCE
    • SOLID-SURFACES
    • THIN-FILMS

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