Microbial Production of Nanolignin from Cotton Stalks and Its Application onto Cotton and Linen Fabrics for Multifunctional Properties

Abstract

Microbial means of nanolignin production from the bulk lignin derived out of cotton stalks could add value to the agricultural biomass, without affecting the environment. Also, such nanolignin can be used to impart multifunctional properties on the surface of cotton and linen fabrics. The bulk lignin was extracted by kraft pulping process from cotton stalks and subjected to controlled microbial hydrolysis by a lignin degrading fungal isolate, Aspergillus oryzae to obtain the nanolignin. For comparison, nanolignins were prepared by two different established processes, high-shear homogenization and ultrasonication. The microbial process yielded 45.3% nanolignin while homogenization and ultrasonication processes yielded 79.50% and 62.60%, respectively. The nanolignins were characterized for size by DLS particle size analyzer, morphology by AFM and SEM, chemical nature by FTIR, glass transition temperature by DSC and crystallite size by XRD. The microbial nanolignin was applied on to cotton and linen fabrics using pad dry cure method using acrylic binder and studied for its multifunctional properties after 5 and 10 wash cycles. Both the fabrics (cotton and linen) treated with nanolignin showed 100% antibacterial activity against Staphylococcus aureus and Klebsiella pneumonia, and, enhanced UV absorbing and antioxidant properties. This study demonstrated the microbial process for production of nanolignin from cotton stalks and protocol to apply nanolignin to impart antibacterial, antioxidant and UV protection properties on the surface of cotton and linen fabrics.