Effect of Laccase-Mediated Biopolymer Grafting on Kraft Pulp Fibers for Enhancing Paper's Mechanical Properties.

Lourdes Ballinas-Casarrubias,Samuel B Pérez,Guillermo González-Sánchez,Eduardo Duarte Villa,Luis Villanueva-Solís,Carlos Espinoza-Hicks,Miguel De Dios Hernández,Alejandro Camacho-Dávila,Hilda Amelia Piñón Castillo

doi:10.3390/polym9110570

Lourdes Ballinas-Casarrubias, Samuel B Pérez + Show 7 more

Open Access

https://doi.org/10.3390/polym9110570

Copy DOI

Abstract

High-resistance paper was manufactured by laccase-grafting of carboxymethyl cellulose (CMC) and chitosan (CPX) on Kraft pulp fiber. The reaction was mediated in the presence of laccase by one of the following polyphenols in the presence of air: gallic acid (GA), vanillic acid (VA) and catechol (1,2–DHB). Enzyme was added at constant loading (24 kg ton−1), 1% pulp consistency, 0.005% CMC, pH = 6.3 ± 0.5 and 2 mM of mediator. CPX content was assessed at two levels (0% and 0.005%). Treated pulps were analyzed by different mechanical tests (ring crush, mullen, corrugating medium test (CMT) flat crush of corrugating medium test and tension). An improvement in these parameters was obtained by biopolymer coupling and selected mediator. When using GA, three parameters increased more than 40%, while ring crush increased 120%. For the case of VA, properties were enhanced from 74% to 88% when CPX was added. For 1,2–DHB, there was not found a statistically significant difference between the results in the presence of CPX. Scanning electron microscopy, confocal microscopy, FTIR and 13C NMR were used in all papers in order to evaluate grafting. Hence, it was possible to correlate polymerization with an improvement of paper’s mechanical properties.

Highlights

Process innovation relies on developing new products and technologies under green chemistry principles
Laccases were used for delignification in the bleaching process of paper [31,32]
Once oxidized, it interacts with the phenolic substrate to generate the oxidized species (Scheme 1)

Summary

Introduction

Process innovation relies on developing new products and technologies under green chemistry principles. Industries are using enzymes for the implementation of eco-friendly technologies. As a result, they can overcome the limitations of physicochemical processes; especially in terms of the new regulation requirements. Among the most-used enzymes in the paper industry are laccases (E.C. 1.10.3.2), which are produced naturally by many microorganisms, principally fungi They catalyze the oxidation of substrates such as phenols and polyphenols with wide oxidative capability, due to their high redox potential [4]. Laccases require oxygen as co-substrate, rendering water as the only byproduct. They are able to oxidize specific phenolic end groups in lignin [5]

Methods

Results

Conclusion