title: Decomposition behavior of hemicellulose and lignin in the step-change flow rate liquid hot water.
abstract: Hemicellulose and lignin are the main factors limiting accessibility of hydrolytic enzymes besides the crystallinity of cellulose. The decomposition behavior of hemicellulose and lignin in the step-change flow rate hot water system was investigated. Xylan removal increased from 64.53% for batch system (solid concentration 4.25% w/v, 18 min, 184°C) to 83.78% at high flow rates of 30 ml/min for 8 min, and then 10 ml/min for 10 min. Most of them (80-90%) were recovered as oligosaccharide. It was hypothesized that the flowing water could enhance the mass transfer to improve the sugars recovery. In addition, the solubilization mechanism of lignin in the liquid hot water was proposed according to the results of Fourier transform-infrared spectroscopy and scanning electron microscopy of the water-insoluble fraction and gas chromatography-mass spectrometry of the water-soluble fraction. It was proposed that lignin in the liquid hot water first migrated out of the cell wall in the form of molten bodies, and then flushed out of the reactor. A small quantity of them was further degraded into monomeric products such as vanillin, syringe aldehyde, coniferyl aldehyde, ferulic acid, and p-hydroxy-cinnamic acid. All of these observations would provide important information for the downstream processing, such as purification and concentration of sugars and the enzymatic digestion of residual solid.
authors.affiliation: Guangzhou Institute of Energy Conversion, Key Laboratory of Renewable Energy and Gas Hydrate, Chinese Academy of Sciences, Guangzhou 510640, China.
authors.forename: Xinshu
authors.initials: X
authors.lastname: Zhuang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yu
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Qi
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wang
authors.forename: Xuesong
authors.initials: X
authors.lastname: Tan
authors.forename: Zhenhong
authors.initials: Z
authors.lastname: Yuan
mesh_terms: D019149:Bioreactors; D002482:Cellulose / Q000737:chemistry; D003373:Coumaric Acids / Q000737:chemistry; D006358:Hot Temperature; D006868:Hydrolysis; D008031:Lignin / Q000737:chemistry* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D011134:Polysaccharides / Q000737:chemistry*; D012212:Rheology / Q000379:methods*; D012995:Solubility; D045868:Sorghum / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water / Q000737:chemistry*; D014994:Xylose / Q000032:analysis
chemical_list: D003373:Coumaric Acids; D011134:Polysaccharides; D014867:Water; C007916:hemicellulose; D002482:Cellulose; D008031:Lignin; C027433:bagasse; D014994:Xylose