| 杨木预水解过程中化学组分的降解行为及P因子调控作用 |
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| 作者姓名： | 任利彤 黎博文 赵思 冯年捷 吴茜 |
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| 作者单位： | 湖北工业大学材料与化学工程学院,武汉 430068;湖北工业大学生物工程与食品学院,武汉 430068 |
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| 基金项目： | 湖北省自然科学基金(4115/00051);湖北工业大学大学生创新创业训练计划(201810500040);湖北工业大学博士生启动基金(BSQD2017016) |
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| 摘 要： | 预水解具有环境友好性,符合生物炼制的理念。前期关于预水解的研究多集中于半纤维素的降解、分离和利用,而有关预水解过程中木质素降解的系统研究鲜有报道。以杨木为原料,在130~210℃条件下保温30~120 min进行预水解,结合P因子研究得率、葡聚糖、木聚糖、酸不溶木质素和酸溶木质素的降解率,揭示P因子对木质素降解行为的调控作用,探讨各化学组分在预水解过程中的相互作用。研究表明,预水解过程中木质素发生了一定程度的碎片化。随温度升高和时间延长,酸不溶木质素降解率均逐渐升高;当温度为190和210℃时,随时间延长,酸溶木质素降解率先升高后降低。试验证明,P因子对杨木木质素的降解具有调控作用。随着P因子增加,酸不溶木质素降解率呈指数上升,且分为快速降解(P因子<1500)和缓慢降解(P因子>1500)两个阶段;酸溶木质素降解率先上升后下降,在P因子为1926时达到最大值45.9%。此外,预水解过程中碳水化合物和木质素的降解具有相互作用关系。碳水化合物的降解为木质素的溶出打开了物理通道,同时木质素的重新吸附阻碍了其进一步降解。
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| 关 键 词： | 杨木 化学组分 预水解 降解 P因子 |
Effect of P factor on degradation of poplar chemistry composition during prehydrolysis process |
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| Authors: | REN Litong LI Bowen ZHAO Si FENG Nianjie WU Qian |
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| Institution: | (School of Materials and Chemical Engineering,Hubei University of Technology,Wuhan 430068,China;School of Food and Biological Engineering,Hubei University of Technology,Wuhan 430068,China) |
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| Abstract: | Prehydrolysis for lignocelluloses biomass bioconversion has attracted the most attention among the conventional hydrolysis methods,due to its environment-friendly process performance.Previous studies mainly focused on the degradation of hemicellulose in lignocellulosic biomass,in which,xylitol and furfural were the main extraction products.However,the hydrolysis of acetyl groups in hemicellulose is of specific interest as acetic acid is produced and catalyzed secondary hydrolysis reactions,which concurrently promotes some lignin fractions dissolution during the prehydrolysis process.Various processes have been developed for highly puritied extraction products isolated from prehydrolysis liquor.However,due to the various and complex lignin produced by the secondary hydrolysis reactions,it is still difficult to achieve the high purity.Therefore,the studies of lignin degradation still require thorough investigation to provide more valuable information to highly puritied extraction products isolated from the prehydrolysis liquor.In this study,poplar was used in the prehydrolysis tests under different conditions.The changes of yields of glucan,xylan,acid-insoluble lignin and acid-soluble lignin were investigated during the temperature of 130-210℃for 30-120 min.Then,the degradation behaviors of the chemical composition were also depicted with P factor to reveal the regulation effect.Based on the above results of the chemical composition degradation,it was further expected to assess the interaction effect of carbohydrate and lignin on the degradation.The results showed that the amount of lignin in lignocellulosic biomass was degraded during the prehydrolysis process due to the break of chemical bond between lignin units,which depended on the reaction temperature and holding time.For the acid-insoluble lignin,the degradation process can be divided into two phases,namely,a fast phase in the initial 30 min,and a slow one from 30 min to 120 min.For the acid-soluble lignin,at the temperature of 190 and 210℃,the degradation showed a fast increase in the initial 30 min and followed by a slow decrease from 30 min to 120 min.There was a regulation effect of P factor on the lignin degradation.For the acid-insoluble lignin,the degradation showed an exponential growth with the increase of P factor.For the acid-soluble lignin,the degradation reached the maximum of 45.9%at P factor of 1926.Besides,the degradation of carbohydrate and lignin had an interaction effect.The degradation of carbohydrate improved the cell wall porosity and permeability in the initial 30 min,which would benefit the dissolution of lignin in the lignocellulosic biomass.However,the readsorption of lignin occurred in the fiber surface from 30 min to 120 min,which would prevent further degradation of lignin. |
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| Keywords: | poplar chemical composition prehydrolysis degradation P factor |
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