title: Understanding the Nonproductive Enzyme Adsorption and Physicochemical Properties of Residual Lignins in Moso Bamboo Pretreated with Sulfuric Acid and Kraft Pulping.
abstract: In this work, to elucidate why the acid-pretreated bamboo shows disappointingly low enzymatic digestibility comparing to the alkali-pretreated bamboo, residual lignins in acid-pretreated and kraft pulped bamboo were isolated and analyzed by adsorption isotherm to evaluate their extents of nonproductive enzyme adsorption. Meanwhile, physicochemical properties of the isolated lignins were analyzed and a relationship was established with non-productive adsorption. Results showed that the adsorption affinity and binding strength of cellulase on acid-pretreated bamboo lignin (MWLa) was significantly higher than that on residual lignin in pulped bamboo (MWLp). The maximum adsorption capacity of cellulase on MWLp was 129.49 mg/g lignin, which was lower than that on MWLa (160.25 mg/g lignin). When isolated lignins were added into the Avicel hydrolysis solution, the inhibitory effect on enzymatic hydrolysis efficiency of MWLa was found to be considerably stronger than that with MWLp. The cellulase adsorption on isolated lignins was correlated positively with hydrophobicity, phenolic hydroxyl group, and degree of condensation but negatively with surface charges and aliphatic hydroxyl group. These results suggest that the higher nonproductive cellulase adsorption and physicochemical properties of residual lignin in acid-pretreated bamboo may be responsible for its disappointingly low enzymatic digestibility.
authors.affiliation: Co-Innovation Center for Efficient Processing and Utilization of Forest Products, Nanjing Forestry University, Nanjing, 210037, China.|College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China.
authors.forename: Caoxing
authors.initials: C
authors.lastname: Huang
authors.affiliation: Co-Innovation Center for Efficient Processing and Utilization of Forest Products, Nanjing Forestry University, Nanjing, 210037, China.|College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China.
authors.forename: Juan
authors.initials: J
authors.lastname: He
authors.affiliation: College of Light Industry Science and Engineering, Nanjing Forestry University, Nanjing, 210037, China.
authors.forename: Douyong
authors.initials: D
authors.lastname: Min
authors.affiliation: Co-Innovation Center for Efficient Processing and Utilization of Forest Products, Nanjing Forestry University, Nanjing, 210037, China.|College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China.
authors.forename: Chenhuan
authors.initials: C
authors.lastname: Lai
authors.affiliation: Co-Innovation Center for Efficient Processing and Utilization of Forest Products, Nanjing Forestry University, Nanjing, 210037, China. swhx@njfu.com.cn.|College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China. swhx@njfu.com.cn.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yong
mesh_terms: D000327:Adsorption; D066241:Carbon-13 Magnetic Resonance Spectroscopy; D002480:Cellulase / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism; D055598:Chemical Phenomena; D006868:Hydrolysis; D007700:Kinetics; D008031:Lignin / Q000737:chemistry* / Q000302:isolation & purification; D010209:Paper; D006109:Poaceae / Q000187:drug effects*; D013464:Sulfuric Acids / Q000494:pharmacology*; D013696:Temperature
chemical_list: D013464:Sulfuric Acids; D002482:Cellulose; D008031:Lignin; D002480:Cellulase; C033158:sulfuric acid
keywords: Adsorption isotherm; Moso bamboo; Nonproductive adsorption; Physicochemical properties; Pretreatment