Study On Isolation、Identification Of Lactic Acid Bacillus And Its Preparation

There is concern that the extensive use of artificial antibiotics is leading to a marked increase in antibiotic resistance among pathogens. Furthermore, certain residual antibiotics in carcasses have a negative effect on the consumer flora and fauna. Lactic Acid Bacillus with the fine features of lactic acid bacteria and Bacillus, and lactic acid production as well as strong resistance, high temperature storage characteristics, and more suitable for the promotion and application in animal husbandry. Experiments were conducted to select lactic acid bacillus from piglet manure, and soil of Northeast Agricultural University, soil of Heilongjiang Academy of Agricultural Sciences effects prevention and treatment of yellow and white scour of piglets by common nutrition medium. And then do a lots of experiments to the aime strains, the result it will provide certain theoretical basis and practical guidance for probiotic preparations used in the actual production. The results were as follows.Using common nutrition medium,26Gram-positive Bacillus of lactic acid bacteria isolated from the bacteria source. At first, Antibacterial performance test to isolated26bacteria, screening have a stronger inhibitory effect of15bacteria to piglet pathogenic bacteria; and then use a pH1.8medium processing train the15strains of bacteria by in vitro acid test screening in liquid2h obtained eight bacteria, this condition showed good tolerability and high activity; Finally, in0.3%bile salt concentration in the liquid medium for2h, filtering out the survival number and survival rates higher strains the Y4, Y6, Y13, Y16.the strain that we want was inoculated in an ordinary nutrient medium at37℃for24h to observe the characteristics and their morphological physiology characteristics as observed under phase contrast microscope:Rod-shaped cells, the end of Health and the formation of oval-shaped spores, spore capsule obvious enlargement, contact enzyme-positive, the4strains were morphologically and physiologically characterized and identified to be the genus Bacillus. Then, through physiological and biochemical tests were identified to be Lactic Acid Bacillus.Experimental Two:Determination the production capacity of acid and digestive enzyme about Y4, Y6, Y13, Y16and Bacillus subtilis, Bacillus licheniformis cultured24h,the results showed that all strains are able to produce a certain amount of digestive enzymes such as amylase production: α-amylase Y16<Y13<Bacillus subtilis<Y4<Bacillus licheniformis<Y6(47.99U/mL). High alkaline protease production of various strains:Y16<Bacillus licheniformis<Y13<Y4<Y6<Bacillus subtilis.various strains of VFA各菌株的VFA产量由低至高为：Y13<Bacillus subtilis <Y4<Bacillus licheniformis<Y16<Y6(259.48mmol/L). Experimental Three: At first determine growth curve of lactic acid bacillus, and then optimization of the liquid fermentation medium. The conclusion that lactic acid bacillus growth curve of live bacteria counting peak appeared at30hours, while the spore number peak appeared at36hours; Experiments indicated that the optimum liquid medium including1%bean cake powder,1%bran powder,1%corn powder,1%glucose,0.3%CaCO3,0.2%K2HPO4,0.002%MnSO4·H2O,0.01%MgSO4·7H2O,0.1%NaCl,100mL H2O. During this fermentation medium composition for fermentation, living bacteria number up to1.95X1012cfu/mL.Experimental Four: in the preparation process of the probiotics, the effectively live bacteria the low-temperature drying temperature is50℃; carrier composition suitable proportion of rice husk: soybean meal is1:3; and then determination of shelf life (the effectively live bacteria). The present results demonstrate that the effectively live bacteria of derived vacuum packaging probiotics significantly higher than the effectively live bacteria of the non-vacuum packaging in shelf life of180d.