Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa 50011.
Appl Environ Microbiol. 1991 Oct;57(10):2821-8. doi: 10.1128/aem.57.10.2821-2828.1991.
A propionic acid-tolerant derivative of Propionibacterium acidipropionici P9 was obtained by serially transferring strain P9 through broth that contained increasing amounts of propionic acid. After 1 year of repeated transfers, a strain (designed P200910) capable of growth at higher propionic acid concentrations than P9 was obtained. An increase in the proportion of cellular straight-chain fatty acids and uncoupling of propionic acid production from growth were observed for strain P200910. Growth rate, sugar utilization, and acid production were monitored during batch and semicontinuous fermentations of semidefined medium and during batch fermentation of whey permeate for both strain P200910 and strain P9. The highest propionic acid concentration (47 g/liter) was produced by P200910 in a semicontinuous fermentation. Strain P200910 produced a higher ratio of propionic acid to acetic acid, utilized sugar more efficiently, and produced more propionic acid per gram of biomass than did its parent in all fermentations.
通过在含有逐渐增加丙酸浓度的肉汤中连续传代,获得了耐丙酸的丙酸丙酸杆菌 P9 衍生物。经过 1 年的反复传代,获得了一株(命名为 P200910)比 P9 能够在更高丙酸浓度下生长的菌株。观察到 P200910 菌株的细胞直链脂肪酸比例增加,并且丙酸的产生与生长解偶联。在半连续发酵和乳清渗透物的分批发酵中,监测了 P200910 和 P9 菌株的分批发酵中,监测了生长速率、糖利用和酸产生。在半连续发酵中,P200910 产生了最高的丙酸浓度(47 g/L)。在所有发酵中,P200910 菌株比其亲本菌株产生更高比例的丙酸和乙酸,更有效地利用糖,并且每克生物质产生更多的丙酸。