Optimization of Lignin Extraction and Isolation of Substituted Hydroxycinnamic Acids from Sugarcane (Saccharum officinarum) Bagasse Lignin Hydrolysate

Abstract The aim of present study was valorization of abundant waste of sugarcane industry i.e. bagasse for the production of lignin-based substituted hydroxycinnamic acids. Alkaline hydrolysis conditions of dilute acid pretreated bagasse for delignification were optimized using response surface met...
Ausführliche Beschreibung

Abstract The aim of present study was valorization of abundant waste of sugarcane industry i.e. bagasse for the production of lignin-based substituted hydroxycinnamic acids. Alkaline hydrolysis conditions of dilute acid pretreated bagasse for delignification were optimized using response surface methodology. Morphological changes in bagasse fibers were monitored through scanning electron microscopic (SEM) images. Lignin hydrolysate was utilized for the isolation of major substituted hydroxycinnamic acids (HCAs). Lignin and isolated compounds were structurally characterized via FT-IR, 1H, 13C NMR and mass spectral techniques and evaluated for their antioxidant potential using 2, 2-diphenyl-1-picrylhydrazyl radical scavenging activity. The optimized conditions for maximum delignification i.e. 81.94 mg lignin/g bagasse were 10.25% (w/v) NaOH, 75.00 min of reaction time and temperature of 100.39 °C. Ferulic acid and p-coumaric acid were isolated in good yields from lignin liquor and characterized by spectral, mass spectrometry and elemental studies. Phenolic extract of lignin liquor in ethyl acetate, from which individual HCAs were extracted using preparative thin layer chromatography, exhibited the higher radical scavenging index followed by ferulic acid, lignin and p-coumaric acid. It was concluded that lignin-based HCAs isolated from bagasse have the potential to be employed as natural and safe antioxidants to prevent autooxidation and rancidity of fats and oils. Ausführliche Beschreibung