Efficient removal of lignin with the maintenance of hemicellulose from kenaf by two-stage pretreatment process

• Published in: Carbohydrate polymers 2014, Vol.99, p.447-453
• Main Authors: Wan Azelee, Nur Izyan, Md Jahim, Jamaliah, Rabu, Amir, Abdul Murad, Abdul Munir, Abu Bakar, Farah Diba, Md Illias, Rosli
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Applied sciences; Biological and medical sciences; Calcium Hydroxide - chemistry; Cellulose and derivatives; Endo-1,4-beta Xylanases - chemistry; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Fungal Proteins - chemistry; General agronomy. Plant production; Hemicellulose; Hibiscus - chemistry; Hydrolysis; Kenaf; Lignin - isolation & purification; Lignin and derivatives; Lignin removal; Natural polymers; Peracetic Acid - chemistry; Physicochemistry of polymers; Polysaccharides - isolation & purification; Pretreatment; Use of agricultural and forest wastes. Biomass use, bioconversion; Xylose - chemistry
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2013.08.043

•A mild pretreatment using combination of alkali–acid (Ca(OH)2–peracetic acid).•High lignin removal with low sugar loss.•The percentage of lignin, hemicellulose and cellulose removal after pretreatment of kenaf is calculated.•Low temperature with short pretreatment time.•The pretreated kenaf shows increased enzymatic hydrolysis compared to the unpretreated kenaf. The enhancement of lignocellulose hydrolysis using enzyme complexes requires an efficient pretreatment process to obtain susceptible conditions for the enzyme attack. This study focuses on removing a major part of the lignin layer from kenaf (Hibiscus cannabinus) while simultaneously maintaining most of the hemicellulose. A two-stage pretreatment process is adopted using calcium hydroxide, Ca(OH)2, and peracetic acid, PPA, to break the recalcitrant lignin layer from other structural polysaccharides. An experimental screening of several pretreatment chemicals, concentrations, temperatures and solid–liquid ratios enabled the production of an optimally designed pretreatment process for kenaf. Our results showed that the pretreatment process has provide 59.25% lignin removal while maintaining 87.72% and 96.17% hemicellulose and cellulose, respectively, using 1g of Ca(OH)2/L and a 8:1 (mL:g) ratio of liquid–Ca(OH)2 at 50°C for 1.5h followed by 20% peracetic acid pretreatment at 75°C for 2h. These results validate this mild approach for aiding future enzymatic hydrolysis.