Structural changes in the crosslinking process of a protein bioadhesive

Abstract

In a previous research study, a protein from Bacillus subtilis was cloned in an overexpressing strain and produced in higher amounts than in natural conditions, with the aim of assessing whether this protein can be a candidate to be considered in the formulation of new biobased, bioinspired adhesives with industrial purposes. A bioadhesion assay, as well as the morphological analysis by scanning electron microscopy and confocal laser scanning microscopy, confirmed the involvement of the protein under study in the biofilm formation and adhesion processes of the bacterium. Furthermore, its suitability for being used as a polymeric base for adhesive formulations was assessed in terms of thermal properties, wettability of different substrates, surface tension, particle size distribution and bondability to polymeric adherends. The results obtained were promising. Nevertheless, it was found that the adhesive should be conveniently formulated in order to improve its performance. In this work, the purified protein has been modified using glutaraldehyde, which is commonly used in protein crosslinking. Structural changes produced in the protein, which could affect its suitable use as an adhesive, were assessed in terms of crystallinity, morphology, thermal properties and spectroscopic properties.