β-胡萝卜素降解菌营养需求和提高酶活力的研究

发布时间：2018-04-04 22:18

本文选题：β-胡萝卜素降解菌　切入点：化学合成培养基　出处：《西北农林科技大学》2012年硕士论文

【摘要】：本试验的β-胡萝卜素降解菌是本实验室分离筛选的，经过初步鉴定和分子鉴定，最终得到的结论是葡萄球菌属的一种革兰氏阳性细菌。类胡萝卜素经过降解，可以生成具有9、10、11和13个碳原子的降异戊二烯化合物（norisoprenoids），如氧化异佛尔酮、β-大马酮、β-紫罗兰酮、假紫罗兰酮和二氢弥猴桃内酯等，这些化合物因为感官阈值较低，对食品香气品质具有较明显影响，可以增加食品的香味，提高食品品质。传统的降解类胡萝卜素方法是光、氧、热等理化方法，，但是这些方法耗能大、成本高、化学污染严重、安全性差，所以现在以微生物酶转化类胡萝卜素为多种芳香物质是一种新的发展趋势，目前国内外研究较少，有很好的理论意义和应用价值，并且微生物酶转化类胡萝卜素生产成本低、专一性强、操作方便、安全性高，并且对环境友好。本试验以β-胡萝卜素降解菌为对象，研究探索出了降解转化β-胡萝卜素的微生物的纯化学合成培养基。采用单一成分缺失的方法确定了菌体生长的营养需求，并对影响酶活力的因素做了初步的研究，试验结果为后续相关机理的研究奠定了基础。本试验主要获得的结论如下：（1）本试验筛选出了适合β-胡萝卜素降解菌体生长的化学合成培养基。确定了培养基的组成成分包括无氨基酵母氮源（YNB）在内共有24种物质，其中包括了碳源、氮源、矿物质和各种生长因子等。（2）通过单一缺失试验确定了菌体生长的必需营养素。共有五种氨基酸是菌体生长所必需的，分别是Gly、Val、Arg、 Pro、Try，另外无机盐K2HPO4和NaNO3也是必需营养素。五种非必需氨基酸分别是Glu、Leu、Lys、Tyr、Thr，其他组分尽管对菌体生长有一定的作用，但缺失时对菌体生长不会受到较大影响。（3）K+、Na+、Mg2+和Fe2+等金属离子其对该β-胡萝卜素降解酶的酶活都具有促进作用。
[Abstract]:The 尾 -carotene degrading bacteria in this experiment were isolated and screened in our laboratory. After preliminary identification and molecular identification, the final conclusion is a Gram-positive bacteria of the genus Staphylococcus.After degradation, carotenoids can produce norisoprenoidsn, a kind of isoprenoidssuch as isophorone, 尾 -malone, 尾 -ionone, pseudoionone and dihydromylenolactone, which have 13 carbon atoms.Because of the lower sensory threshold, these compounds have obvious influence on food aroma quality, which can increase the flavor of food and improve the quality of food.Traditional methods for the degradation of carotenoids are light, oxygen, heat and other physicochemical methods, but these methods consume large amounts of energy, are costly, cause serious chemical pollution, and have poor safety.Strong specificity, easy to operate, high safety, and friendly to the environment.In this experiment, the pure chemical synthesis medium of 尾 -carotene degrading bacteria was studied.The nutrient requirement of bacterial growth was determined by the method of single component deletion, and the factors affecting enzyme activity were preliminarily studied. The results laid a foundation for further study on the related mechanism.The main conclusions of this experiment are as follows:1) the chemical synthetic medium suitable for the growth of 尾-carotene degrading bacteria was selected.A total of 24 substances, including carbon sources, nitrogen sources, minerals and growth factors, were identified as the components of the culture medium, including the non-amino yeast nitrogen source (YNB).2) the essential nutrients for cell growth were determined by single deletion test.There are five kinds of amino acids which are essential for cell growth: Glycine Vala Arg Protry and inorganic salts K2HPO4 and NaNO3 are also essential nutrients.The five non-essential amino acids were Glu-LeuLysLys-Tyr-Thr.Although the other components had a certain effect on the growth of the bacteria, they did not have a significant effect on the growth of the bacteria when they were absent.The activities of 尾 -carotene degrading enzyme were promoted by metal ions such as K ~ (3 +), Na ~ (2 +), mg ~ (2 +) and Fe2.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R151

【参考文献】