Non-productive adsorption of bacterial β-glucosidases on lignins is electrostatically modulated and depends on the presence of fibronection type III-like domain

Non-productive adsorption of cellulases onto lignins is an important mechanism that negatively affects the enzymatic hydrolysis of lignocellulose biomass. Here, we examined the non-productive adsorption of two bacterial beta-glucosidases (GH1 and GH3) on lignins. The results showed that beta-glucosidases can adsorb to lignins through different mechanisms. GH1 beta-glucosidase adsorption onto lignins was found to be strongly pH-dependent, suggesting that the adsorption is electrostatically modulated. For GH3 beta-glucosidase, the results suggested that the fibronectin type III-like domain interacts with lignins through electrostatic and hydrophobic interactions that can partially, or completely, overcome repulsive electrostatic forces between the catalytic domain and lignins. Finally, the increase of temperature did not result in the increase of beta-glucosidases adsorption, probably because there is no significant increase in hydrophobic regions in the beta-glucosidases structures. The data provided here can be useful for biotechnological applications, especially in the field of plant structural polysaccharides conversion into bioenergy and bioproducts. (C) 2016 Elsevier Inc. All rights reserved.