AP BIOLOGY

Detailed explanation-1: -Lactobacillus is a genus of bacteria which can convert sugars into lactic acid by means of fermentation. Milk contains a sugar called lactose, a disaccharide(compound sugar) made by the glycosidic bonding between glucose and galactose (monosaccharides). Lactobacillus bacteria are helpful in a formation of curd.

Detailed explanation-2: -Complete answer: Lactobacillus is responsible for spoiling/fermenting/curdling of the milk. Lactobacillus is a gram-positive bacteria used commercially in the dairy industry to make many dairy-related products.

Detailed explanation-3: -Lactobacillus converts lactose, the sugar in milk, to lactic acid during fermentation. The lactic acid being acidic, coagulates the milk proteins which results in the formation of curd.

Detailed explanation-4: -They make lactic acid by breaking down carbohydrates. This is mainly done by breaking down the sugar lactose in milk. Lactobacilli grow well in milk and foods made from milk. They’re responsible for the “souring” of milk.