What microorganism is used to prepare yogurt and buttermilk?

Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus are the microorganisms that are used to prepare yogurt and buttermilk. These microorganisms are responsible for the fermentation of milk, which results in the production of yogurt and buttermilk.

Lactobacillus delbrueckii subsp. bulgaricus is a rod-shaped, Gram-positive bacterium. It is a facultative anaerobe, meaning that it can grow in both the presence and absence of oxygen. Lactobacillus delbrueckii subsp. bulgaricus produces lactic acid as its main metabolic product.

Streptococcus salivarius subsp. thermophilus is a spherical, Gram-positive bacterium. It is a facultative anaerobe, meaning that it can grow in both the presence and absence of oxygen. Streptococcus salivarius subsp. thermophilus produces lactic acid as its main metabolic product.

The combination of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus is essential for the production of yogurt and buttermilk. These microorganisms work together to ferment milk, producing lactic acid and other metabolic products that give yogurt and buttermilk their characteristic flavor and texture.