本文選題：β-胡蘿卜素降解菌　切入點：化學(xué)合成培養(yǎng)基　出處：《西北農(nóng)林科技大學(xué)》2012年碩士論文

【摘要】：本試驗的β-胡蘿卜素降解菌是本實驗室分離篩選的，經(jīng)過初步鑒定和分子鑒定，最終得到的結(jié)論是葡萄球菌屬的一種革蘭氏陽性細菌。類胡蘿卜素經(jīng)過降解，可以生成具有9、10、11和13個碳原子的降異戊二烯化合物（norisoprenoids），如氧化異佛爾酮、β-大馬酮、β-紫羅蘭酮、假紫羅蘭酮和二氫彌猴桃內(nèi)酯等，這些化合物因為感官閾值較低，對食品香氣品質(zhì)具有較明顯影響，可以增加食品的香味，提高食品品質(zhì)。傳統(tǒng)的降解類胡蘿卜素方法是光、氧、熱等理化方法，，但是這些方法耗能大、成本高、化學(xué)污染嚴重、安全性差，所以現(xiàn)在以微生物酶轉(zhuǎn)化類胡蘿卜素為多種芳香物質(zhì)是一種新的發(fā)展趨勢，目前國內(nèi)外研究較少，有很好的理論意義和應(yīng)用價值，并且微生物酶轉(zhuǎn)化類胡蘿卜素生產(chǎn)成本低、專一性強、操作方便、安全性高，并且對環(huán)境友好。本試驗以β-胡蘿卜素降解菌為對象，研究探索出了降解轉(zhuǎn)化β-胡蘿卜素的微生物的純化學(xué)合成培養(yǎng)基。采用單一成分缺失的方法確定了菌體生長的營養(yǎng)需求，并對影響酶活力的因素做了初步的研究，試驗結(jié)果為后續(xù)相關(guān)機理的研究奠定了基礎(chǔ)。 本試驗主要獲得的結(jié)論如下： （1）本試驗篩選出了適合β-胡蘿卜素降解菌體生長的化學(xué)合成培養(yǎng)基。確定了培養(yǎng)基的組成成分包括無氨基酵母氮源（YNB）在內(nèi)共有24種物質(zhì)，其中包括了碳源、氮源、礦物質(zhì)和各種生長因子等。 （2）通過單一缺失試驗確定了菌體生長的必需營養(yǎng)素。共有五種氨基酸是菌體生長所必需的，分別是Gly、Val、Arg、 Pro、Try，另外無機鹽K2HPO4和NaNO3也是必需營養(yǎng)素。五種非必需氨基酸分別是Glu、Leu、Lys、Tyr、Thr，其他組分盡管對菌體生長有一定的作用，但缺失時對菌體生長不會受到較大影響。 （3）K+、Na+、Mg2+和Fe2+等金屬離子其對該β-胡蘿卜素降解酶的酶活都具有促進作用。
[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.
【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：R151

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