Studies on the interaction of the carbohydrate binding module 3 from the Clostridium thermocellum CipA scaffolding protein with cellulose and paper fibres

Abstract

The adsorption of a carbohydrate binding module (CBM3) from the Clostridium thermocellum scaffolding protein (CipA) to cellulose was analysed in this work. The effect of CBM-PEG on the drainability of E. globulus and P. sylvestris pulps and on the physical properties of the respective papersheets was also studied. The CBM binding to cellulose is often described as ''irreversible'', but this classification does not fully characterize this interaction. Indeed, the results obtained demonstrate that, although the adsorption on cellulose is rather stable, CBM inter-fibre mobility may be observed. The results also showed that the CBM-PEG conjugate improves the drainability of E. globulus and P. sylvestris pulps without affecting the physical properties of the papersheets.

Modification of paper properties using carbohydrate-binding module 3 from the Clostridium thermocellum CipA scaffolding protein produced in Pichia pastoris: elucidation of the glycosylation effect

“…E. globulus fibers were refined at 3000 revolutions in a PFI mill (ISO 5264/2) while the other pulp was used as supplied. Fibers were treated with the recombinant CBMs essentially as described in Machado et al (2009). Briefly, the CBM3wt or CBM3mt was allowed to adsorb on the fibers by mixing vigorously the protein at the ratio of 2 or 4 mg per gram of pulp (relative to oven dry pulp, i.e.…”

“…Thus, in recent years, research has focused on the use of CBMs and CBM-CBM fusions obtained recombinantly from the bacterium Escherichia coli to enhance the mechanical properties of paper, particularly those related to paper strength (Cadena et al 2010;Levy et al 2002Levy et al , 2004Shi et al 2014). Among the different recombinant CBMs tested, recombinant CBM3, originally from the Clostridium thermocellum scaffolding protein CipA, was reported not to affect pulp and paper properties (Machado et al 2009). Nevertheless, when conjugated with polyethyleneglycol (PEG), recombinant CBM3 improved pulp drainability, without affecting the paper properties (Machado et al 2009).…”

“…Among the different recombinant CBMs tested, recombinant CBM3, originally from the Clostridium thermocellum scaffolding protein CipA, was reported not to affect pulp and paper properties (Machado et al 2009). Nevertheless, when conjugated with polyethyleneglycol (PEG), recombinant CBM3 improved pulp drainability, without affecting the paper properties (Machado et al 2009). This result was attributed to a stabilizing effect of PEG in fibers, driven by the high hydrophilic nature of that molecule, which was used to mimetize glycosylation in CBM3 (Machado et al 2009).…”

“…Nevertheless, when conjugated with polyethyleneglycol (PEG), recombinant CBM3 improved pulp drainability, without affecting the paper properties (Machado et al 2009). This result was attributed to a stabilizing effect of PEG in fibers, driven by the high hydrophilic nature of that molecule, which was used to mimetize glycosylation in CBM3 (Machado et al 2009). In fact, nonglycosylated CBMs have shown the opposite effect: they increase considerably the hydrophobicity of fibers (Levy et al 2002) and reduce pulp drainage (Cadena et al 2010).…”

“…CBMs with linked oligosaccharides are thought to stabilize the fibers due to steric effects, thus reducing the interfiber interactions in water suspensions (Pinto 2006). However, despite the several indications that glycosylation may be essential for the positive effects of CBMs in cellulose fibers (Machado et al 2009;Pinto 2006), this subject has not yet been thoroughly studied.…”