Initial Assessment of Lignin Recovery From Sugarcane Bagasse and Its Potential Use in Sunscreen Formulations

Abstract

Saccharum officinarum (sugarcane) is a perennial tropical crop grown in Malaysia for its raw cane sugar production. Sugarcane bagasse, which is the fibrous part left after the cane juice extraction has an average amount of lignin content (17%–25%) which has previously shown to have anti‐UV properties. The limited valorization of sugarcane bagasse and the ongoing ozone layer depletion have led to the study of lignin extraction and its efficacy in blocking UV radiation. This study aims to optimize organosolv lignin extraction method from sugarcane bagasse for high lignin recovery. The sugarcane bagasse used in the study has been characterized to contain 16.7% lignin and the organosolv lignin extraction method was further optimized using Box‐Behnken design (BBD) to achieve the highest lignin yield. The lignin was extracted under reflux with three manipulated parameters of reaction time (2–6 h), concentration of catalyst (0–0.4 M), and liquid/solid ratio (10/1–50/1 v/w). The lignin extracted from the optimized parameters was characterized for its surface morphology (VPSEM), functional groups (FTIR), thermal stability (TGA) and sun protection properties (SPF). Through this study, it is determined that the best extraction condition yielded 42.95% of lignin when performed at 5.75 h of reflux duration, 0.357 M of catalyst concentration and 27/1 of liquid/solid ratio. Remarkably, when 10% (w/w) of the extracted organosolv lignin is incorporated, the SPF value of a base cream increased by more than seven folds to 104.58 which highlight its potential as a biobased UV filter in sunscreen. This study shows that biomass lignin is highly potential as a UV protection agent which can be incorporated into sunscreens.