Extraction and characterisation of lignin from sim-sim stems and g.nut stalks

Abstract

Lignocellulosic biomass has been known for potential use to produce chemicals and biomaterials. Lignin is the second most abundant natural polymer with cellulose being number one of Lignocellulosic biomass. Lignin is a three-dimensional, highly cross-linked macromolecule composed of three types of substituted phenols, which include: coniferyl, sinapyl, and p-coumaryl alcohols by enzymatic polymerization, yielding a vast number of functional groups and linkages. This research was intended to extract lignin from Sim-sim stems and G.nut stalks by sodium hydroxide treatment. Isolated lignin was characterized by Fourier transform infrared spectroscopy (FTIR) for chemical composition and function groups. The analysis of FTIR spectra revealed that the chemical structure of lignin varies depending on its species and the isolation method employed. The melting apparatus also revealed that lignin obtained from g.nut stalks had a high melting point compared to lignin from sim-sim stems. It was found that lignin obtained from sim-sim provided the greatest yield of 15.7% compared to lignin from G.nut stalks of 13.9% by weight yielding low lignin.