Development of Lignin Extraction Process from Coconut Coir Fiber Using Acid-Assisted Organosolv Technique to Increase Yield and Biological activity Efficiency

Lignin, the second most abundant biopolymer after cellulose, is the central focus of this study. The research aims to harness the potential of coconut (Cocos nucifera) residues, a versatile tropical plant native to South Asia, known for its contributions in food, fuel, folk medicine, and construction materials. More specifically, the study delves into the lignin present in coconut, with a special emphasis on coconut coir fibers as the raw materials for lignin extraction. 

       The extraction process employs acid-assisted organosolv technique to effectively purify the lignin from the coconut coir fibers. The ethanolic extraction process eliminates extractives from the biomass as the initial step. These extractives, which may contain organic compounds such as wax, lipids, gums, resins, flavonoids, and essential oils, are removed using Soxhlet extraction with 95% ethanol. The extractive-free biomass was thus used for lignin extraction by organosolv extraction method. The organosolv extraction is conducted on a laboratory scale, involving the use of acid (H₂SO₄ or HCl)) as catalysts compared to organosolv extraction without a catalyst. The process variables, such as solid-to-liquid ratio, acid concentration, temperature, and residence time, will then be optimized using response surface methodology (RSM) to determine the best combinations of concentrations, temperatures, and times, leading to improved lignin yields and purity.

       Subsequently, the extracted lignin will undergo characterization based on chemical properties (SEM, FTIE, TGA, DSC, NMR, GPC, etc.) and antioxidant activity, including total phenolic hydroxyl content, DPPH assay, and ABTS assay. By investigating lignin extraction from coconut coir fiber using these methods and characterizing the obtained lignin, this study aims to contribute valuable insights into the potential application of coconut-derived lignin as an antioxidant agent.