Mechanism And Application Of Microbial Bioconversion Of Cholesterol In Food

One idea of Darless Darwin' theory, as presented in his book on the Origin of Species, is that all of animals and plants originated from an ancestor. It was the same in many aspects of all of living things such as the chemical composition, construction of cell, laws of growth, and response to harmful affection.The study of modern biology had probed deeply into the level molecules. It was known that all of biological functions of living things were corresponded with some molecule which structure is definitive. All of biologic molecules were the same in that the structure of a molecule decided the biological function, which was affected by conditions surrounding the molecule, i.e., the environment surrounding the molecules affected the relationships between structures and functions.The main content of molecular biology was to know the relationship between structures and functions of living materials at the level of molecules. It had broken with the classical convention that the biological phenomena were studied over the levels of cells of animals, plants and microorganisms and went into the deep layers to recognize the nature and law of life. The modern molecular biological technology was established on the basis of the pattern of the variation of structure and function of biological molecules and the mutual actions between biological molecules in nature.Any of great advances of biology will produce a great impact on food science for being the basic science of food processing. Relationship between structure and function of food molecules was step by step known for the advance of molecular biology and had been the basis of theory of modern function food. If molecular biological technique extends into the domain of food processing, process technology of food molecules would be established. It was proved by facts that the basic theory and technology of molecular biology was universal in the fields of biology and related sciences.This paper researched mainly on the mechanism of bio-converting cholesterol in food by microorganism and it's application. The aim of decreasing theunnecessary cholesterol in food was at the regulation of quantity absorbed in body and keeping the stable equilibrium of cholesterol in the inner environment to lower the rate of incidence of disease of blood vessels of heart-brain.It described the general features such as the structure, function, distribution, absorption, metabolism and regulation of cholesterol. The features of five ways in regulation of the level of cholesterol in serum of the body were compared and analyzed, which were: (Dto control the synthesis in the body, ?to break down the cholesterol cycle of liver-intestines"with not dissolving complex integrated cholesterol with a inert compound, ?being on a diet,@removing cholesterol contained in foods by physical and chemical mathods .?byconversion of cholesterol in food by cholesterol oxidase. It showed that the way of converting cholesterol in food by cholesterol oxidase from microorganisms was the better.!n the experiments 103 samples collected from feces of carnivorous and herbivorous animals, fruit and vegetable, fermented foods and soils. 107 bacterial strains that utilize cholesterol as sole carbon and energy sources were isolated from the samples. 39 strains were selected by comparing the rate of growth and the quantity of acid produced in the medium. 4 strains were picked out by determining their Gram stain reaction, shape, endospore forming, litmus milk test and morphological characteristics of their colonies. Finally, one of those strains, No.TI2-l was chosen by tests the substrate-using versatility of bacteria by measuring growth of the organisms 131 different media and the extracellular cholesterol oxidase activity and was identified as aerobic bacillus sp.The cholesterol oxidase produced by strain No.T12-l was purified from the culture broth by procedures including anion exchange chromatography, Hydroxyapatie, gel filtration and uitrafiltratiom. This research had laid the foundation of analysis of series of amino acid of cholesterol oxidase and to transfer the gene of cholesterol oxidase to plants.