Leuconostoc

Leuconostoc is a genus of gram-positive bacteria, placed within the family of Lactobacillaceae. They are generally ovoid cocci often forming chains. Leuconostoc spp. are intrinsically resistant to vancomycin and are catalase-negative (which distinguishes them from staphylococci). All species within this genus are heterofermentative and are able to produce dextran from sucrose. They are generally slime-forming. The name Leuconostoc comes from Greek adjective leukos meaning clear; and the word nostoc gelatinous colonies, Leuconostoc - colorless nostoc. Blamed for causing the 'stink' when creating a sourdough starter, some species are also capable of causing human infection. Because they are an uncommon cause of disease in humans, standard commercial identification kits are often unable to identify the organism. Leuconostoc spp., along with other lactic acid bacteria such as Pediococcus and Lactobacillus, are responsible for the fermentation of cabbage, making it sauerkraut. In this process, fresh cabbage is fermented in a light brine, where the sugars in the cabbage are transformed by lactofermentation to lactic acid which gives the cabbage a sour flavour and good keeping qualities. Leuconostoc spp. are similarly part of the symbiotic colonies of bacteria and yeast (SCOBY) involved in the fermentation of kefir, a fermented milk beverage and kombucha, a fermented tea.