Champagne Claude P., Gaudreau Helene, Conway John, Chartier Nathalie, Fonchy Evelyne
Food Research and Development Center, Agriculture and Agri-Food Canada, 3600 Casavant Blvd. West, St. Hyacinthe QC, Canada J2S 8E3.
J Gen Appl Microbiol. 1999 Feb;45(1):17-21. doi: 10.2323/jgam.45.17.
An automated spectrophotometric (AS) method was used to evaluate the growth-promoting ability of yeast extracts (YE) on cultures of Lactobacillus acidophilus and Lactococcus lactis subsp. cremoris. The AS data were compared to that obtained from classical shake flask fermentations and from 250 ml bioreactors equipped with pH control. In assays involving the evaluation of 26 different commercial YE, maximum growth rate (&mgr;(max)) values determined with the AS unit ranged from 0.25 to 0.45 h(-1) for Lb. acidophilus and from 0.10 to 0.40 h(-1) for Lc. cremoris. Good correlations were obtained between AS data and manual sampling from the shake flasks or the bioreactors for mmax, as well as maximum optical density (OD(max)). The AS method is thus useful as a screening tool for the selection of YE lots in media formulation. Species reacted differently to the 26 YE, but less variation was observed between strains of the same species. This suggests that a producer of various lactococci or lactobacilli can expect a relatively constant response to a given YE lot between strains of the same species. However, it should not be assumed that the YE having the best growth-promoting properties for Lb. acidophilus will also be the best media supplements for the growth of Lc. cremoris.
采用自动分光光度法（AS）评估酵母提取物（YE）对嗜酸乳杆菌和乳酸乳球菌亚种乳脂亚种培养物的促生长能力。将AS数据与通过经典摇瓶发酵以及配备pH控制的250 ml生物反应器获得的数据进行比较。在涉及评估26种不同商业YE的试验中，AS装置测定的嗜酸乳杆菌最大生长速率（μm(max)）值范围为0.25至0.45 h(-1)，乳脂亚种乳酸乳球菌的最大生长速率值范围为0.10至0.40 h(-1)。对于最大生长速率以及最大光密度（OD(max)），AS数据与摇瓶或生物反应器的手动取样之间获得了良好的相关性。因此，AS方法可用作在培养基配方中选择YE批次的筛选工具。不同菌种对26种YE的反应不同，但同一菌种的菌株之间观察到的差异较小。这表明，各种乳酸球菌或乳酸杆菌的生产商可以预期同一菌种的菌株对给定YE批次的反应相对恒定。然而，不应假定对嗜酸乳杆菌具有最佳促生长特性的YE也将是乳脂亚种乳酸乳球菌生长的最佳培养基补充剂。
