细胞表面蛋白介导乳酸菌絮凝淀粉机制及其对淀粉加工性质的影响

项目名称： 细胞表面蛋白介导乳酸菌絮凝淀粉机制及其对淀粉加工性质的影响

项目编号： No.31301499

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 农业科学

项目作者： 张莉力

作者单位： 辽宁医学院

项目金额： 22万元

中文摘要： 微生物发酵酸浆法絮凝淀粉主要在甘薯和绿豆淀粉生产中应用，是我国民间传统工艺，该技术的特点是淀粉经微生物絮凝后，粉丝加工性质得到明显改善，是粉条类产品加工的优质原料。但是，近年来，由于该工艺排放的废水中含有大量乳酸菌活细胞造成环境污染，且淀粉改性的机制也不明确，严重限制了酸浆法技术的推广应用。本项目将在甘薯酸浆微生物学研究的基础上，以筛选到的、高絮凝活性的副干酪乳杆菌L1为研究对象，分离纯化位于菌体细胞表面的絮凝因子--淀粉结合蛋白，以絮凝率为指标，研究蛋白质与淀粉的结合条件，确定蛋白质脱离菌体后对其絮凝淀粉活性的影响；同时，利用质谱、生物信息等技术鉴定、预测蛋白质结构及淀粉结合位点，从蛋白质分子水平上阐明乳酸菌与淀粉结合机制；并在此基础上，通过扫描电镜、X射线衍射等研究该结合作用对于淀粉结构及加工性质的影响，为淀粉絮凝剂的开发应用和酸浆法技术生产粉条专用淀粉奠定理论基础和提供技术支撑。

中文关键词： 乳酸菌；絮凝；淀粉；淀粉结合蛋白；

英文摘要： The traditional technology with naturally fermented sour liquid mainly used for the production of sweet potato starch and mung bean starch has hundreds of years, which starch gained an extensive application in vermicelli processing for its unique character. However, there are a large number of bacteria and organic compounds in the discharged wastewater, which seriously cumbers the technology wide application in starch processing. The protein mediating the adhesion to starch is to be separated and purificated from the Lactobacillus paracasei subsp. paracasei L1 with high flocculating activity on base of the microbiological study of sweet potato sour liquid. Then, starch-binding protein of L1 is as the research object and identified by mass spectrometry. Starch-bingding properties, spatial structure and starch-bingding sites of the protein are then studied to reveal the molecular mechanism of Lactobacillus paracasei subsp. paracasei L1 adhesion to starch. Fanally, the crystal structure and chemical composition and character of starch adhered by protein are studied to reveal the effect of protein on the starch. Therefore, this study is beneficial to the development of flocculant for starch and the wide application of sour liquid technology in special starch for processing vermicelli.

英文关键词： Lactic acid bacteria；flocculation；starch；starch-binding protein；