Lactobacillus sanfranciscensis
| Lactobacillus sanfranciscensis | |
|---|---|
| Scientific classification | |
| Domain: | Bacteria |
| Phylum: | Firmicutes |
| Class: | Bacilli |
| Order: | Lactobacillales |
| Family: | Lactobacillaceae |
| Genus: | Lactobacillus |
| Species: | L. sanfranciscensis |
| Binomial name | |
| Lactobacillus sanfranciscensis (ex Kline & Sugihara 1971) Weiss & Schillinger 1984 | |
Lactobacillus sanfranciscensis (formerly L. sanfrancisco) is a species of lactic acid bacteria which, through the production mainly of lactic and acetic acids, helps give sourdough bread its characteristic taste. It is named after San Francisco, where sourdough was found to contain the variety, though it is not endemic to the area.[1]
Sourdough starters are leavened by a mixture of yeast and lactobacilli in a ratio of about 1:100. The yeast is most commonly Candida humilis. This yeast cannot metabolize the maltose found in the dough, while the Lactobacillus requires maltose.[2] They therefore act without conflict for substrate, with the Lactobacillus utilizing maltose and the yeast utilizing the other sugars, including the glucose produced by the Lactobacillus.
External conditions such as acidity and temperature affect the growth rates of Lactobacillus sanfrancisco. One study found that of temperature of 33C (91F) leads to maximum growth rates, whereas temperatures over 41C (105F) completely inhibit the bacteria growth. Ideal and max growth temperatures of other organisms may be quite different; for instance a common yeast in sourdough, Candida milleri, prefers 27C (81F) and will not grow above 36C (97F).[3]
For commercial use, specific strains of the L. sanfranciscensis are grown on defined media, freeze-dried, and shipped to bakeries worldwide.
References
- ↑ Karel Kulp; Klaus Lorenz (2003). Handbook of Dough Fermentation. CRC Press. ISBN 0-8247-4264-8.
- ↑ Neubauer H, Glaasker E, Hammes WP, Poolman B, Konings WN (1994). "Mechanism of maltose uptake and glucose excretion in Lactobacillus sanfrancisco". J Bacteriol. 176 (10): 3007–12. PMC 205458
. PMID 8188601. - ↑ Ganzle MG, Ehmann M, Hammes WP (1998). "Modeling of Growth of Lactobacillus sanfranciscensis and Candida milleri in Response to Process Parameters of Sourdough Fermentation". Appl Environ Mocrobiol. 64 (7): 2616–2623. PMC 106434.