Lactic acid production from a mixture of cultures of Lactococcus lactis and Streptococcus salivarius using batch fermentation

Production of lactic acid (LA), yield (Yp/s) and substrate conversion (SC) from Lactococcus lactis, Streptococcus salivarius and their mixtures were tested. Lactococcus lactis was selected from 20 homofermentative strains isolated from a sugar cane crop (variety CC85-92) and Streptococcus salivarius was isolated from a commercial lactic ferment. Batch fermentation experiments at 32 C with a glucose concentration of 60 gL-1 and a pH of 6,0 were carried out. A maximum of 47,63 gL-1 of lactic acid concentration, 95,4% of substrate conversion and 83 gg-1 were obtained from the mixture of strains after a fermentation of 48 h. Key words: sugar cane, Lactococcus lactis, Streptococcus salivarius, mixture of strains