Elucidation of structure-inhibition relationship of monosaccharides derived pseudo-lignin in enzymatic hydrolysis

Pseudo-lignin is defined as aromatic material, which could be formed through dehydration synthesis and aromatisation of carbohydrate. 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.