Plackett-Burman法筛选保加利亚乳杆菌发酵培养基氮源

研究了酸奶发酵菌种保加利亚乳杆菌的增菌培养基组成，考查了7种氮源对其生长的影响．以廉价易得的原料作为基础培养基，采用Plackett—Burman（PB）试验设计筛选了影响保加利亚乳杆菌生长的重要因素．结果表明：新生牛血清（p=0．0253）、酵母粉（p=0．0707）、酪蛋白水解物（p=0．0939）3种氮源对保加利亚乳杆菌的增殖效果比较明显，三者在大于90％的概率水平上差异显著，新生牛血清、酵母粉呈负效应，酪蛋白水解物成正效应．其他因素在大于90％的概率水平上差异不显著．因此，可选择该3种物质作为保加利亚乳杆菌的增殖因子．初步确定了3种氮源的添加量，为进一步优化确定培养基奠定了基础．

Screening nitrogen source of fermentation medium of Lactobacillus bulgaricus by Plackett-Burman design

As one of the yogurt fermentation bacterias-Lactobacillus bulgaricus, of which en- richment medium components, was optimized after examined seven kinds of nitrogens which affected its growth. Based on the cheap and readily available raw materials, the important factors that influnce on the growth of Lactobacillus bulgaricus were filtered with Plackett- Burman （PB） experimental design method. The results showed that three kinds of nitrogen sources of newborn calf serum（p=0. 025 3）, yeast extract（p=0. 070 7） and casein hydroly- zate （p=0. 093 9）had a significant affect on the growth of Lactobacillus bulgaricus, which showed significant differences in more than 90% probability level. What＇s more, newborn calf serum and yeast extract showed a negative effect, the casein hydrolyzate had a positive effect. The other factors did not show significant differences in more than 90% probability level. So we chosed the three substances as the multiplication factors of Lactobacillus bulgar- icus. The trials initially identified the amount of three kinds of nitrogen sources in order to laid the foundation for further optimization of medium for the future.