乳酸菌的分离筛选及其微生态制剂的制备

Isolation and screening of lactic acid bacteria and preparation of microbial ecological agents

该研究用市售酸奶中分离纯化到的乳酸菌株和实验室保藏的多种乳酸菌株作为材料,研究不同乳酸菌对大肠杆菌、沙门氏菌、志贺氏菌、金黄色葡萄球菌4种致病菌株的抑菌作用。采用双层平板法从出发菌株中选育到对致病菌株有明显抑制功能的乳酸菌,并将抗菌性能良好的乳酸菌株进行优化组合。组合菌剂转接到脱脂乳中,静置培养48h后,采用真空冷冻干燥技术制备乳酸菌微生态制剂。试验结果表明,从原始菌株中选育到11株对4种致病菌有较强抑制功能的乳酸菌株;优化组合乳酸菌在MRS培养液中,静置培养17h活菌数达到最大值;冷冻干燥过程采用2%麦芽糖作为保护剂,微生态制剂中乳酸菌活菌数为3.36×105cfu/g,存活率达到68.6%。

Antibacterial effect of lactic acid bacteria purified from yogurt and preserved in our laboratory on pathogenic strains of Higellae pathogenic, Staphylococcus aureus, Salmonella, and Escherichia coli were studied. Double-plate method was adopted to select lactic acid bacteria that had a significant inhibition function on pathogenic strains, and lactic acid bacteria strains with good anti-bacterial performances was combined and optimized. Combined strains were inoculated with skim milk to produce microbial ecological agents of lactic acid bacteria by vacuum freeze-drying after 48h static culture. The experimental results shown that among the original lactic acid bacteria strains, eleven strains had significant inhibition effect on the four pathogenic strains, and the number of optimized combination reach its peak after 17h static culture in MRS medium. When using 2% of maltose as protective agent, the number of survival bacteria was 3.36x 105cfu/g, the survival rate of lactic acid bacteria in microbial ecological agents after vacuum freeze-drying could reach 68.6%.