Abstract

ESPINOZA-ACOSTA, JL et al. Extraction, characterization and antioxidant activity of lignin from water hyacinth (Eichhornia crassipes) and pecan nut shell (Carya illinoinensis). Biotecnia [online]. 2022, vol.24, n.2, pp.94-103.  Epub May 19, 2023. ISSN 1665-1456.  https://doi.org/10.18633/biotecnia.v24i2.1642.

In this work, the potential of water hyacinth (Eichhornia crassipes) and pecan nutshell (Carya illinoinensis) as a source of lignin was investigated. The lignin extraction was carried out using an organosolv procedure and was characterized by infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The antioxidant activity was determined through the stabilization of the DPPH and ABTS free radicals. The results showed higher lignin content and extraction performance in pecan nutshells. The infrared spectrum revealed typical bands of the main functional groups; phenolic -OH groups, C - H3 methyl groups, and O-CH3 methoxyl which are part of the lignin aromatic ring. The water hyacinth lignin (LLA) showed high resistance to thermal degradation which places it as an interesting component for the development of phenolic resins or flame retardants. The lignin extracted from pecan nutshell (LCN) showed a high percentage of inhibition against DPPH and ABTS radicals when solubilized in ethanol, methanol, and ethanol-methanol mixtures (50:50 v/v). The high antioxidant activity of LCN indicates that this type of lignin may have applications in the food and pharmaceutical industries.

Keywords : Lignin; water hyacinth; pecan nutshell; antioxidant activity.