Studies On Screening Of Bacterial Strains Producing Elastase And Function Property Of Elastase

Elastase is a kind of broad-spectrum endopeptidase that can degrade specially undissolvable elastin, which also belongs to serine protease family. Elastase benefits the bodies of people in many aspects, such as effecting on lipid metabolism, reducing cholesterin, inhibiting the development of arteriosclerosis, promoting the lipid hydrolyzation in liver as to preventing experimental liver fibrosis and fat liver, reducing blood pressure, helping to resist the lack of oxygen, protecting cardiac muscle and preventing diabetes. Furthermore, as the resource, elastase can be made into high-class cosmetics that postpone the aging of people. In food industry, elastase can be made into the new type of enzyme preparation because of its excellent tenderizing effect. Nutrient and functional foods can be researched and produced when many originally inedible protein resources, such as ligaments and tendons, are processed by elastase, so food resources will be widened and the additional values of animal by-product will be improved. In many previous studies, it was indicated that elastase has broad applications in medical therapy, food industry, consumer goods industry, chemistry industry and so on. Thus, elastase is a kind of widely-used functional protease, and it has a wide market prospect. Nowadays elastase has high production costs and low yields, which is almost isolated from animal pancreas home and abroad, limit its application fields. Short supply of animal pancreas causes the high price of commercial elastase. So in China, elastase is only used in medicament, and its application in food industry still rests on the experimental stage. In this study, elastase-producing strain was screened, isolated and breed, and we got 1 strain from 46 possible strains which came from cattle stomach. Elastase morphologic character and biochemical characteristic was systematically studied. And investigated its capability of producing elastase, optimized its culture conditions and fermentation technology,and subsequently established the temperature-changed constant and dynamic model of fermentation. We purified the elastase with the aid of SephadexG-75 column chromatograph and SDS-PAGE, and studied its enzymology property as well as its kinetics of enzyme-catalyzed reactions. Later elastase hydrolyzation and tenderizing effect on meat was studie, contrasted the operating characteristic of elastase to that of other existing protease, finally set up the model of its kinetics of enzyme-catalyzed reactions.l.Obtainning elastase-producing strain that has high growth speed and steady capability of producing elastase with high enzyme activity from the animal by-product (cattle stomach) by screening and mutagenetic technique.The strain that had higher growth speed and stable capability producing elastase with high activity had was obtained from 25 kinds of animal by-products (cattle stomach) by microbiology screening and compound mutagenetic techniques. It was studied systematically on morphology feature, growth characteristics, physical and biochemical property. Under the microscope, research results sljow that the strain was a kind of Gram-negative bacillus and they had middle-sized cells (length: 2.53um, width: 0.64um) that were singly arranged in disorder without spores, but both ends of the cell were a little arc. It could grow well on the peptone medium, and form a protruding light yellow round bacterial colony, and there was apparently clear zone around the bacteria colony when cultured in elastin medium. The growth state varied with the cultural temperature, and the cultural time of the strain was the shortest at the temperature from 37 to 40 , usually 18-24h. By observing the bacteria under dark-field microscope, it was found that could move slightly along a straight way. The bacterium, capable of producing elastase, was a kind of chemoheterotrophic microbe, and its tests of oxidase and peroxidase both produced positive result. Cultured at 37 , the bacteria could produce pigment which was deep green on neutral and alkalin...