Production of lactic acid from cheese whey by batch cultures of Lactobacillus helveticus

The production of lactic acid by Lactobacillus helveticus from a cheese whey residue obtained from a dairy was investigated. Batch fermentation experiments showed that the optimal temperature to carry out the process was 42°C and the optimum pH was 5.9, giving at these conditions a maximum concentration of lactic acid of 53 g/l. The addition of yeast extract to the cheese whey residue as a nitrogen source for L. helveticus did not increase the lactic acid production significantly. The results obtained in this work confirmed that it is possible to increase the value of residues from the dairy industry for the production of value-added products such as lactic acid, which has important industrial applications. Also, the effect of the addition of a nitrogen source to the culture media of the fermentation experiments did not present a cost-beneficial improvement on lactic acid production as other authors have shown. The last finding could reduce the cost of the culture media used for lactic acid production when scaling up the process.