Lactobacillus delbrueckii subsp. bulgaricus Lactobacillus delbrueckii subsp. bulgaricus Lactobacillus delbrueckii" subsp. "bulgaricus (until 2014 known as Lactobacillus bulgaricus) is the main bacteria used for the production of yogurt. It is also found in other naturally fermented products. First identified in 1905 by the Bulgarian doctor Stamen Grigorov, the bacterium feeds on lactose to produce lactic acid, which is used to preserve milk. "Lactobacillus delbrueckii" subsp. "bulgaricus" can be found naturally in the gastrointestinal tract of mammals living in Bulgaria, but one specific strain, "Lactobacillus bulgaricus" GLB44, is extracted from the leaves of the "Galanthus nivalis" (snowdrop flower) in Bulgaria as well. The bacterium is
Chlamydomonas nivalis optimal position in the snow for moisture content, light, and temperature. When in the immotile cyst stage, the "C. nivalis" cells must depend on the flow of meltwater to move it by chance to a favourable area. The temperatures in which this species can survive in ranges from below 0 °C to just above 20 °C. Growth is slow when temperatures are below 5 °C. At 5-15 °C the growth of "C. nivalis" cells can outperform the growth of C. reinhardtii cells. Both species grow at the same rate at 20-25 °C. The growth of "C. nivalis" is suppressed when