Enzymatic degradation of lignin extracted from oil palm empty fruit bunch using laccase and cutinase

Abstract

Enzymatic degradation products of lignin, having potential for added value, were obtained by extraction and subsequent enzymatic treatments of oil palm empty fruit bunch (OPEFB). The objective was to optimize the production of OPEFB lignin degradation products and study the effects of different enzymes and reaction media. Powder of OPEFB lignin was recovered from organsolv black liquor by using methanol, acidified water, and deionized water, respectively. OPEFB lignin was later subjected to enzymatic hydrolysis in an incubator shaker for 24 h using laccase and cutinase in various reaction media, including phenol, water, and acetate buffer. Nine compounds were recovered as OPEFB lignin degradation products, namely hydroxybenzoic acid, hydroxybenzaldehyde, vanillic acid, vanillin, syringic acid, syringaldehyde, coumaric acid, ferulic acid, and guaiacyl alcohol. When laccase was used in water, the product with the highest concentration was syringaldehyde (4061.1 ± 89.9 mg/L), and followed by hydroxybenzoic acid (1029.8 ± 50.2 mg/L). Vanillic acid was the product with the highest concentration (126 ± 97.5 g/L) found when laccase was used in phenol. When cutinase was used in water, products with the highest concentrations in the medium were syringaldehyde (4837.6 ± 156.4 mg/L) and syringic acid (2387.7 ± 105.3 mg/L). High performance liquid chromatography (HPLC) was used to quantify the OPEFB lignin degradation products.