On the Surface Interactions of Proteins with Lignin

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 β-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 ~40° and 35° for undenatured 11S and 7S, respectively) is explained by strong nonspecific interactions between soy proteins and lignin.

Self-association and aggregation of kraft lignins via electrolyte and nonionic surfactant regulation: stabilization of lignin particles and effects on filtration - OPEN ACCESS

“…The self-associative behavior of KL has been studied already (Lindström 1980;Lindström 1979;Norgren et al 2002;Nyman et al 1986;Ratnaweera et al 2015) and has been considered as that of typical polyelectrolytes in aqueous media (Helander et al 2013). This has been relevant to our recent reports on the synthesis of supracolloidal lignin particles (Nypelö et al 2015;Ago et al 2016Ago et al , 2017 and their interactions with proteins (Cusola et al 2014;Fritz et al 2015;Hoeger et al 2012;Rahikainen et al 2013;Salas et al 2012). Here, dispersion interactions and hydrogen bonding, among others, affect the colloidal stability in aqueous dispersions.…”

Lignin-based polyoxyethylene ether enhanced enzymatic hydrolysis of lignocelluloses by dispersing cellulase aggregates

“…The mechanism of enhancing the enzymatic hydrolysis of microcrystalline cellulose with high lignin content by EHL-PEG 3.2.1. Effect of EHL-PEG on the nonproductive adsorption of cellulase on the lignin film QCM-D has been reported to monitor the adsorption behavior of polyelectrolyte (Norgren et al, 2007), soy protein (Salas et al, 2013) and cellulase (Rahikainen et al, 2013;Sammond et al, 2014) on the lignin film in real time dynamics. Here, QCM-D was used to investigate the effect of EHL-PEG and PEG4600 on the nonproductive adsorption of cellulase on the lignin film.…”

Efficient and Supplementary Enzyme Cocktail from Actinobacteria and Plant Biomass Induction

“…On the other hand, 4% (w/v) of bagasse showed total protein of ≈180 mg L −1 , which was lower than expected. This was assumed due either to enzyme nonspecific adsorption on lignin or to the activation of some repressor, such as catabolite repression . So 2.5% (w/v) of pretreated bagasse proved to be the optimal amount for inducing secretion in a biomass‐degrading enzyme cocktail.…”