Adsorption of bovine serum albumin on the surfaces of poplar lignophenols.

Two phenolic compounds (p-cresol and pyrogallol) were introduced into the benzyl position of poplar lignin by a phase separation method to obtain lignin-based derivatives with different structural properties called poplar lignophenols (LPs). The maximum protein adsorption capacity of LPs is 50-70 times greater than that of the industrial lignin under the same conditions. The interaction between poplar LPs and bovine serum albumin (BSA) near its isoelectric point (pH = 4.5) was studied using a quartz crystal microbalance with dissipation monitoring (QCM-D). The adsorption and desorption of BSA molecules on different LPs were investigated at various pH values of the buffer solution (2.1, 6.4, and 10.0), and the interaction mechanism between LP and BSA species was examined. The obtained results showed that hydrogen bonding was the strongest binding force between LPs and BSA as compared with hydrophobic and electrostatic interactions. The findings of this work can help to establish a relationship between the contents of hydroxyl groups, molecular structures, and molecular sizes of LPs and proteins under different pH conditions.