Comparison of delignification of oil palm empty fruit bunch (EFB) by microwave assisted alkali / acid pretreatment and conventional pretreatment method

Abstract

Pretreatment of lignocellulosic biomass are key technologies for the production of fermentable sugars to produce biofuels and high value added organic acids. Microwave-Alkali (MW-A) pretreatment is an efficient, time saving and fast method to remove a high amount of lignin. Lignin content of the oil palm biomass was determined after Microwave-Alkali (Mw-A) pretreatment and conventional pretreatment methods. In conventional pretreatment, empty fruit bunches (EFB), was soaked in 2.5 M NaOH for 2 hours in autoclave. While, in microwave assisted dilute acid/ alkali, the EFB was soaked in dilute sulphuric acid by conventional autoclave heating which remove 90 % of hemicellulose. In the second step, acid treated EFB was soaked in 2.5 M NaOH solution, and applied for microwave pretreatment. The amount of acid insoluble lignin was determined by klason’s method. The results revealed that lignin obtained from untreated EFB was 24.87, conventional heating autoclave pretreatment 16.34, microwave- alkali dilute acid/alkali treated 8.67 (g/100gm). The results showed that a high amount of lignin 71.91% of lignin has removed by microwave assisted alkali/acid pretreatment as compared with conventional heating (34.65 %).