摘要
引言
木质纤维素类生物质的生化转化过程包括预处理过程、水解液发酵过程和产物分离过程,而预处理过程是减少整个生化转化成本和提高生化转化效率的关键[1-3]。与其他预处理方法相比,高温液态水处理（liquid hot water）（温度在170～250℃,压力高于饱和蒸气压）是一种绿色处理方法,
Sweet sorghum bagasse（SSB）was hydrolyzed with liquid hot water in a flow-through reactor with the objective of achieving complete saccharification of hemicellulose of SSB and understanding the hydrolysis mechanism.The effect of reaction temperature（155—235℃）and flow rate（5—30 ml·min-1）on the concentration of xylose,glucose,arabinose,their total sugars and their degradation products（furfural,5-HMF,acetic acid,glucuronic acid,formic acid and glycolic acid）in the liquid fractions was investigated.The experimental results indicated that xylose was more sensitive to temperature and flow rate than arabinose and glucose.The concentration of total xylose including xylose monomer and xylose oligomer dropped dramatically when temperature was higher than 195℃.A lower flow rate（5 ml·min-1）resulted in a higher furfural yield due to longer residence time for xylose in the reactor.In contrast,a higher flow rate（30 ml·min-1）would reduce the thickness of stagnant fluid layer surrounding the solid particles and lower resistance to penetration of water into the solids for hydrolysis and diffusion of oligomers into solution.It was hypothesized that the major xylan in SSB hemicellulose was O-acetyl-4-O-methyl-glucuronoarabinoxylan.Xylose,arabinose,glucose and their oligosaccharides could be considered as the primary products.Glucuronic acid and acetic acid were produced from the decomposition of glucuronic and O-acetyl groups in the branched chain of hemicellulose.Furfural and 5-hydroxymethyl-2-furaldehyde（5-HMF）were the direct degradation products of sugars.Moreover,glucuronic acid would be further oxidatively degraded into glycolic acid.Low molecular weight organic acids,such as formic acid were the further degradation products.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2012年第2期599-605,共7页
CIESC Journal
基金
国家科技支撑计划项目(2011BAD22B01)
国家高技术研究发展计划项目(2010AA101606)
中国科学院知识创新工程项目(KSCX2-YW-G-063,KSCX1-YW-11-A3)~~
关键词
高温液态水
甜高粱渣
水解
半纤维素
机理
liquid hot water
sweet sorghum bagasse
hydrolysis
hemicellulose
me chanism
