脂肪酶催化合成松香淀粉酯的反应机制及其产物的结构和性能研究

Esterification is an important research direction in the modification of starch; the research group used rosin acid, a characteristics resource of Guangxi Province, as acyl donor for the modification of cassava starch, to synthesize rosin acid starch esters with lipase catalyzed. At present, there is little basic theory research on the enzymatic synthesis of rosin acid starch esters. In this project, the basic theory and application foundation relative to the reaction mechanism on enzymatic synthesis of rosin acid starch esters, and the structure-properties relationship of the esterified products will be researched..By systematically analyzing the effect of solvent system on reactants’ structure and reactivity during the process of rosin acid starch esters synthesis catalyzed by lipase, especially the effect of interaction between the auxiliary solvent and the reactive hydroxyl groups on starch granule, and the effect of interaction between the auxiliary solvent and the rosin acid molecules in the solvent system; studying the influence of solvent system and water molecule on the structure, conformation and stability of lipase; optimizing the enzymatic reaction conditions, and investigating the relationship between reaction conditions and substitution degree(DS) of the esterified products, deducting kinetic equation of the enzymatic reaction of rosin acid starch ester synthesis. Based on the research above, the interaction models between substrates and reaction environment, enzyme and reaction environment, enzyme and substrates will be constructed, and the reaction mechanism of enzymatic synthesis of rosin acid starch esters will be explained. .In addition, the structure and physicochemical properties of rosin acid starch esters will be analyzed and characterized, the structure-properties relationship of esterified products will be studied in this research, that will be benefit to the development and application of the new starch ester.

酯化修饰是目前淀粉改性的重要研究方向，课题组利用广西特色资源松香酸作为酰基供体，在脂肪酶催化下对木薯淀粉进行酯化修饰，合成新型的松香酸淀粉酯。针对目前酶促松香酸淀粉酯合成中应用基础理论研究较为欠缺的问题，本课题针拟在酶促反应机制、酯化产物构效关系的基础理论和应用基础开展研究。.通过系统分析脂肪酶催化松香酸淀粉酯合成过程中溶剂体系对反应物结构及反应活性的影响，特别是溶剂体系中辅助溶剂与淀粉粒上反应羟基以及松香酸分子的相互作用；研究溶剂体系、水分子对脂肪酶结构、构象及稳定性的影响；优化酶促反应条件并分析反应条件与产物取代度相关性，推导酶促合成松香酸淀粉酯的反应动力学；构建反应过程中底物与反应环境、酶与反应环境、酶与底物的相互作用模型，探讨酶促合成松香酸淀粉酯的反应机制。.课题还将对松香酸淀粉酯结构及各项理化性质进行深入的表征分析，研究酯化反应产物的构效关系，为新型淀粉酯的开发及应用提供参考。

酯化修饰是目前淀粉改性的重要研究方向，课题组利用广西特色资源松香酸作为酰基供体，在脂肪酶催化下对木薯淀粉进行酯化修饰，合成新型的松香酸淀粉酯。针对目前酶促松香酸淀粉酯合成中应用基础理论研究较为欠缺的问题，项目在木薯淀粉原料预处理的影响、酶促合成松香酸淀粉酯的反应机制、松香酸淀粉酯的结构性能研究三个方面开展了研究工作。.项目系统研究了微波法、湿热法、超声法、预糊化法以及碱处理法等预处理对木薯淀粉的影响;探讨了在乙醇溶液中，通过添加不同碱、不同盐对木薯淀粉进行热处理，在有效维持木薯淀粉形貌不变，有效改变其晶型及相对结晶度，使之易于进一步的改性反应。对酶促合成松香酸淀粉酯的反应过程进行优化研究，建立了RAS合成工艺中反应温度、物料比、酶加入量对DS影响的数学模型。此外，开展了非均相条件下，脂肪酶催化/非酶促直接在淀粉颗粒表面进行疏水修饰改性的研究。对不同DS的RAS的结构及性质进行表征分析，根据酯化产物结构性质，对其在苯类污染物吸附、药物负载、乳液稳定的应用开展了研究。.研究工作期间，我们发现，对木薯淀粉纳米化处理后，修饰反应效率较高，课题组随后在沉降法制备木薯淀粉纳米颗粒，淀粉纳米颗粒的疏水改性及应用方面展开工作，取得显著进展。.课题还为新型淀粉酯的开发及应用提供了参考。