Jose Martinez Chamas, Maria Cristina Rubio, and Pedro Aredes Fernandez*
*Facultad de Bioquímica Química y Farmacia – Instituto de Biotecnología – UNT, Ayacucho 471, 4000, Argentina (pedroaredes@hotmail.com)

The preservation of starter cultures for malolactic fermentation (MLF) of wines is necessary for their following use. The conservation is regularly carried out at low temperatures in a suitable medium. The conservation of a starter culture and its fermentation activity depend on the method of conservation selected and the environment in which the conservation is carried out. The Oenococcus oeni RAM10 strain was grown in a novel designed medium (M7) to promote biomass production and improve malolactic activity. We evaluated the effect of the medium on cell viability and the loss of fermentative capacity (LFC) after culture conservation by refrigeration, freezing with glycerol, and lyophilization with glutamate, fructose, and grape juice as protective agents. Grown and conserved cultures in M7 showed less LFC than those preserved in conventional MLO (control medium) for refrigeration and freezing conservation methods. The viability did not show significant differences for both media during refrigeration. The conservation of O. oeni by freezing in both media with glycerol exhibited greater cell viability. However, cultures conserved in M7 induced MLF with lower LFC (17%) than MLO, which had an LFC of 24% until three months of storage. Lyophilization in MOP7 in the presence of glutamate and grape juice maintained high viability until six months of storage, with a LFC of 20 and 25%, respectively. Fructose showed a lower lioprotective effect and a high LFC at the same time. Storage in MOP7 permitted conservation of cultures with the least LFC after refrigeration, freezing, or lyophilization methods. Lyophilization using grape juice as the lioprotector preserved the cultures for at least six months. This protective agent has the advantages of being inexpensive and easy to access.

Funding Support: Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)