Screening Formula Of Nutrients For Beta-Carotene-Degradating Microorganisms And Improve The Enzyme Activity

The beta-carotene-degradating microorganism is screened by ourselves in our lab. Afterthe initial identification and molecular identification, it is belong to staphylococcus and is agram-positive bacteria. After degradation, norisoprenoids such as isophorone, β-damascenone,β-ionone, pesudoionone and dihydroactinidiolide, which carried9,10,11and13carbonatoms will be obtained. These compounds have low sensory threshold values, which affect thefood aroma quality, increase the food odour and therefore improve food quality. Thetraditional methods of degradating beta-carotene are physicochemical methods such as Light,oxygen, heat and et al. But these methods have lot of defects, such as big energy consumption,high cost, the chemical pollution, poor safety et al. So the microbial enzymes degradatecarotenoids into a variety of aromatic materials is a developing tendency now. There are just alittle research in this field in our country and abroad and have very good theoreticalsignificance and application value. Microbial enzymes transformation of carotenoids havemany advantages, low cost, the strong specificity, convenient operation, high safety, friendlyto environment and so on. The goal of this research was to study on thebeta-carotene-degradating microorganism, found out a new chemically defined medium,determined the nutritional requirements of the bacteria growth by single omission techniqueand studied on the factors of influence on the enzyme activity. The experimental result was afoundation for the subsequent related mechanism study.This experiment mainly obtained the results as follows:(1) Screened and obtained a suitable chemically defined medium, determined24compounds in the medium include carbon source, nitrogen source, minerals andvarious growth factor etc.(2) Determined essential nutrients of the bacteria growth by single omission technique.The essential nutrients included five kinds of amino acid(Gly、Val、Arg、Pro and Try)and two kinds of inorganic salt(K2HPO4and NaNO3); the non-essential nutrientswere Glu、Leu、Lys、Tyr and Thr. Others were Stimulatory compounds.(3) The metal ion of K+、Na+、Mg2+and Fe2+were having stimulative effect in the aspect of improving enzyme activity.