亚硝酸盐还原酶发酵工艺研究
时间:2016-12-20 19:44 来源:毕业论文 作者:毕业论文 点击:次
| 摘要：亚硝酸盐作为氮循环的中间产物，是潜在的致癌物质，在多数食品中均有检出。近年来，亚硝酸盐含量超标已对食品、水质、养殖和环境等造成了不同程度的危害。本课题利用乳酸菌产生亚硝酸还原酶，首先对亚硝酸钠加入的时间进行研究，通过相同时间的培养可知，亚硝酸钠在乳酸菌培养6h后加入的降解量比直接加入的增加了9.12µg/mL，降解效果更好。其次，在培养基氮源的研究中，氮源，即硝酸钠或硫酸铵，含量越高，降解效果越好；而酵母膏的最适添加量为7g，此时亚硝酸钠降解效果最好；当氮源为硝酸钠时，乳酸菌在培养2h后加入亚硝酸钠的降解量达到最高，为96µg/mL，而氮源为硫酸铵是，8h后加入的降解量最高，为71.44µg/mL。最后，研究了海藻酸钠固定化的工艺，得到最适包埋率为4%，加了菌悬体的废水在6h后降解效果明显增加，18h内降解17.9µg/mL。4609 关键词：亚硝酸钠；乳酸菌；海藻酸钠固定；发酵罐 Study on fermentation technology of nitrite reductase Abstract: Nitrite, as intermediate product of the nitrogen cycle, is potential carcinogens and detected in most of the food. In recent years, the nitrite content exceed the standard of food, water, aquaculture and the environment, resulting in varying degrees of damage. This topic using lactic acid bacteria produced nitrite reductase, the first study of sodium nitrite added time, through the cultivation of the same time, sodium nitrite and cultured in 6h after adding lactic acid bacteria degradation than directly adding increased 9.12µg/mL, the degradation effect is better. Secondly, in the research of medium nitrogen source, nitrogen source, namely sodium nitrate or ammonium sulfate, the higher the concentration, the degradation effect is better; and the yeast extract the optimum adding amount of 7g, the best time of sodium nitrite degradation effect; when the nitrogen source for sodium nitrate, sodium nitrite degradation of adding lactic acid bacteria in the 2h after the train reached the highest, 96µg/mL as nitrogen source, and ammonium sulfate is added, 8h degradation was the highest, 71.44µg/mL. Finally, the process of sodium alginate was studied; the optimal embedding rate was 4%, and the wastewater bacteria suspension degradation effect increased significantly after 6h, 18h degradation of 17.9µg/mL. Key Words: Sodium nitrite；Lactic acid bacteria；sodium alginate fixed；Fermentation tank 目 录 毕业设计(论文) 1 1绪论 1 1.1 亚硝酸盐简介 1 1.2 亚硝酸盐的国内外研究现状概述 1 1.2.1 亚硝酸盐在食物中的来源 1 1.2.2 目前国内外降解亚硝酸盐的方法 2 1.2.3 细胞固定化技术 4 1.3 本课题的研究目的和意义 5 1.4 研究内容 5 2材料和方法 6 2.1 材料 6 2.1.1 实验菌种： 6 2.1.2 实验试剂 6 2.1.3 培养基 6 2.1.4 实验设备 7 2.2 实验方法 8 2.2.1 亚硝酸钠的测定：盐酸萘乙二胺法 8 2.2.2 降解亚硝酸钠的测定 9 2.2.3 培养基氮源的研究 10 2.2.4 培养基氮源的优化 10 2.2.5 不同加样时间对降亚硝酸钠的研究 11 2.2.6 菌体海藻酸钠固定化降解亚硝酸钠 11 3结果与分析 13 3.1 降解亚硝酸钠的研究 13 3.1.1 降解亚硝酸钠的测定 13 3.1.2 培养基氮源的研究 14 (责任编辑：qin) |