The effect of the lignin isolation method from oil palm empty fruit bunch black liquor for seed coating material

Lignin has potency as a seed coating treatment for preserving seed from deterioration prior to plant and prevent seed growth quickly. Nonetheless, given the complexity of lignin characteristics, it is necessary to develop isolation methods to ensure appropriate utilization, particularly for seed coating. This study intended to observe the oil palm empty fruit bunch (OPEFB) lignin for seed coating treatment and evaluate the effect on chili seed growth. Previously, lignin was extracted by inorganic acid, specifically H2SO4 and HCL, via a precipitation method with washing treatment of 3 and 5 times. The effectiveness of lignin as seed coating was evaluated by soaking chili seeds in a lignin-NaOH solution. The results showed that HCl-isolated lignin has a higher purity of 91.62% compared to H2SO4-isolated lignin after 5 washing treatments. Meanwhile, H2SO4-isolated lignin has a higher yield of 19.29%. The syringyl/guiacyl (S/G) ratio of isolated lignin by HCl and H2SO4 with different washing treatments ranges from 0.97 to 1.97. Thermal analysis reveals that HCl-isolated lignin is more stable than H2SO4-isolated lignin, with a mass residue of 49.4%. The glass transition (Tg) ranges from 126.42 to 168.05 degrees C. The result showed that the shelf life of lignin-coated seed was up to 30 weeks at room temperature and more resistance to fungal contaminants. Germination of chili-coated seeds occurs in the second to fourth weeks after the planting period.