458 / 2018-09-05 09:57:11

Unveiling the structural properties of pseudo-lignin and its impact on the enzymatic hydrolysis of cellulose

全体主题 > 生物质液体燃料

Pseudo-lignin is defined as aromatic material, which could be formed through dehydration synthesis and aromatisation of carbohydrate. It has been hypothesized that pseudo-lignin could bond with melted lignin and deposit on the surface of lignocellulose, which would block cellulase access to the substrate and decrease enzymatic efficiency. From the biofuel production perspective, it’s significant to further understand the inhibitory mechanisms empirically observed between cellulolytic enzymes and pseudo-lignin.
In this work, dilute sulfuric acid was carried out to treat monosaccharides and holocellulose to generate pseudo-lignin and the residual lignin (RL) in acid-pretreated bamboo was isolated. The structural informations of pseudo-lignin were assayed by nondestructive techniques (SEM, FTIR, and 31P NMR). Meanwhile, the nonproductive adsorption performance of pseudo-lignin and cellulase was evaluated, taking RL as the comparison. Results showed that pseudo-lignin represented sensible droplets and was consist of aliphatics, carbonyl and aromatic structures. The amounts of aliphatic hydroxyl groups and carboxylic acid in pseudo-lignin were 0.61-0.79 mmol/g and 0.64-0.68 mmol/g, respectively. Total OH content of RL (3.51 mmol/g) was higher than pseudo-lignins (2.52-3.05 mmol/g). Due to the lower negative surface charge, hydrophobic nature, Langmuir constant (K) and binding strength (R) of pseudo-lignin, it represented weaker negative impact on enzymes than RL.