Translations:Lactobacillus acidophilus/6/en
Metabolism
L. acidophilus is a homofermentative anaerobic microorganism, meaning it only produces lactic acid as an end product of fermentation; and that it can only ferment hexoses (not pentoses) by way of the EMP pathway (glycolysis). L. acidophilus has a slower growth time in milk than when in a host due to limited available nutrients. Because of its use as a probiotic in milk, a study done by the American Journal of Dairy Science examined the nutrient requirements of L. acidophilus in an effort to increase its low growth rate. The study found that glucose and the amino acids cysteine, glutamic acid, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tyrosine, valine, and arginine are essential nutrients to the growth of L. acidophilus, with glycine, calcium-pantothenate, and Mn2+ acting as stimulatory nutrients. The study helps to explain the low growth rate of L. acidophilus in milk, as some of the amino acids necessary to L. acidophilus growth are lacking in milk. Adding amino acids with high rates of consumption to fermented milk is a possible solution to the problem.