Biological activities and thermal behavior of lignin from oil palm empty fruit bunches as potential source of chemicals of added value

The lignin is the most important renewable source of aromatic compounds on earth. It could represent up to 40% of dry matter in a biomass, however, its potential is underestimated being used as heat recovery source in industrial processes. Therefore, this work aimed to show the chemical feature of lignin isolated from sequential acid-alkaline pretreatment of oil palm empty fruit bunches. The extracted lignin was subjected to studies of this thermal behavior and biological properties as antioxidant, antimicrobial, and antidiabetic. The 2D HSQC spectroscopy analysis showed syringyl aromatic structure and presence of aromatic rings in lignin. The antioxidant assay showed that 2 mg of lignin were required to inhibit 50 wt.% DPPH, while the antimicrobial test inhibited the growth of Escherichia coli, Salmonella enterica serovar thyphimurium, Bacillus subtilis and Staphyloccocus aureus. The antidiabetic assay revealed inhibition of 20% of alpha-amylase activity. The thermogravimetric analysis gave out two peaks of decomposition at 230 degrees C and 350 degrees C and the glass transition temperature at 70 degrees C. These results showed the potential of lignin as precursor of chemicals of added value in a biorefinery process using as feedstock oil palm empty fruit bunches. (C) 2016 Published by Elsevier B.V.