Leuconostoc mesenteroides : Application and Prospects

Leuconostoc mesenteroides as a bacterium associated with vegetable fermentations has been familiar to humane being since long time. This organism initiates the desirable lactic acid fermentation in these products. This bacterium differs from other lactic acid species in that it can tolerate fairly high concentration of salt and sugar (up to 50% sugar). Recently a strong interest about this strain has been extensively increased because these bacteria can produce functional foods such as various type of glucans, high quality of oligosaccharides, and mannitol. Dextransucrase of L. mesenteroides synthesizes either linear α-1,6 glucose linkage or branched type (α-1,6 glucose backbone and α-1,4, α -1,3, and α-1,2 glucose branch) glucan. Glucans are used for food ingredients such as dietary fiber, texturizer, and anticaking agent. For medical field they have been used as blood plasma expenders and blood flow improvers. The recent studies have showed the strong possibility that the controlled size of glucans could be used for new drug delivery agents. In the presence of other sugars, called acceptors, the dextransucrase is shifted toward oligosaccharides synthesis by successive transfers of the glucose residue of sucrose to the non-reducing end of the acceptor. These oligosaccharides have a strong applicability to cosmetic, food, and medical ingredients. Another important product by this strain is mannitol. Mannitol dehydrogenase of L. mesenteroides converts fructose to mannitol. As the demand of natural product increased, bio-techniques to produce natural mannitol by whole cells or enzymes have been emerged.