不同金属盐强化乙醇/水预处理对蔗渣酶解效率的影响  

Effects of different metal salts enhanced ethanol/H2O pretreatment on enzymatic hydrolysis of sugarcane bagasse

作　　者：蔡战磊 张贤滨 韩雪艳 谢君[1] 张红丹[1] CAI Zhanlei;ZHANG Xianbin;HAN Xueyan;XIE Jun;ZHANG Hongdan(Institute of Biomass Engineering,South China Agricultural University,Guangzhou 510642,China)

机构地区：[1]华南农业大学生物质工程研究院,广州510642

出　　处：《农业工程学报》2024年第8期207-215,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家重点研发计划项目(2021YFC2101603);国家自然科学基金项目(21978108)联合支持。

摘　　要：预处理过程可以破坏木质纤维素生物质的致密结构、降低生物抗性,是木质纤维素生物质经酶解制备糖基平台化学的重要步骤。该研究以蔗渣为原料,在预处理温度为160℃、预处理时间为10 min时,选取0.025 mol/L的不同金属盐FeCl_(3)、CrCl_(3)、AlCl_(3)、CuCl_(2)、FeCl_(2)、ZnCl_(2)、MnCl_(2)、MgCl_(2)、CaCl_(2)、NaCl、LiCl、Na_(2)CO_(3)对蔗渣进行乙醇/水预处理,并对预处理后样品进行酶解,探究不同金属盐强化乙醇/水预处理对蔗渣酶解效率的影响和规律,并进一步通过扫描电镜(scanning electron microscopy,SEM)、X射线衍射(X-ray diffraction,XRD)、傅里叶变换红外光谱(fourier transform infrared spectroscopy,FT-IR)和热重(thermogravimetric,TG)对蔗渣原料和预处理后的固体进行表征,探究金属盐强化乙醇/水预处理后蔗渣表面形貌与结构变化对酶解效率的影响,分析作用机理。结果表明:与原料甘蔗渣相比,不同金属盐强化乙醇/水预处理后样品中葡聚糖的质量分数从45.5%增加到77.2%,预处理后样品酶解48h后的葡萄糖得率也由51.14%增加到最高93.08%。其中,三价金属盐(FeCl_(3)、CrCl_(3)和AlCl_(3))对蔗渣酶解效率的提升最为显著,这可归因于三价金属盐强化乙醇/水预处理可以更加有效的去除蔗渣中的半纤维素和木质素,增加酶对纤维素的可及性。后续表征分析也表明经过三价金属盐(FeCl_(3)、CrCl_(3)和AlCl_(3))强化乙醇/水预处理后的样品比经过二价金属盐(CuCl_(2)、FeCl_(2)、ZnCl_(2)、MnCl_(2)、MgCl_(2)和CaCl_(2))和一价金属盐(NaCl、LiCl和Na_(2)CO_(3))强化乙醇/水预处理表面结构破坏更为彻底,结晶度相对增加最大,木素和半纤维素去除率最多,热稳定性也相对最高。该研究结果将为后续木质纤维素生物质的高效转化与利用提供参考。Pretreatment has been one of the most important procedures to convert the lignocellulosic biomass into the sugarbased chemicals.The dense structure of lignocellulosic biomass can be destroyed to reduce the biological resistance.This study aims to investigate the influence of pretreatment on the enzymatic hydrolysis of sugarcane bagasse,the compositions of solid residue,and pretreatment liquid.The 0.025 mol/L metal salts(FeCl_(3),CrCl_(3),AlCl_(3),CuCl_(2),FeCl_(2),ZnCl_(2),MnCl_(2),MgCl_(2),CaCl_(2),NaCl,LiCl,and Na_(2)CO_(3))were selected to enhance the ethanol/H2O.The pretreatment was conducted at 160°C for 10 min.Compared with the raw sugarcane bagasse,the glucan content in the metal salt-enhanced ethanol pretreated samples increased from 45.5%to 77.2%.The sugars in the pretreatment solution were mainly xylose.There was the low content of glucose,indicating that the metal salts was effectively removed the hemicellulose and lignin during ethanol/H2O pretreatment.In the enzymatic hydrolysis of pretreated samples,the efficiency of metal salts on enzymatic hydrolysis was ranked in the descending order of:trivalent metal salt(FeCl_(3),CrCl_(3)and AlCl_(3)),divalent metal salt(CuCl_(2),FeCl_(2),ZnCl_(2),MnCl_(2),MgCl_(2)and CaCl_(2)),and monovalent metal salt(NaCl,LiCl and Na_(2)CO_(3)).Furthermore,the surface morphology and structure in the native sugarcane bagasse and pretreated solids were characterized by scanning electron microscopy,X-ray diffraction,Fourier transform infrared spectroscopy and thermogravimetric.SEM images showed that the morphological structure of bagasse changed more violently with the increase of metal hydrochloric acid degree,ranging from the original smooth surface to the rough,where many irregularly shaped fine particles appeared,even a large number of cracks and pores.XRD analysis showed that the crystallinity of bagasse raw materials was 51.9%.Furthermore,the crystallinity was improved differently in the various metal salts after pretreatment.Among them,the most crystallinity was found

关 键 词：生物质 盐 蔗渣 乙醇/水预处理 酶水解 葡萄糖 

分 类 号：TK6[动力工程及工程热物理—生物能]