Development of a sweet whey-based medium for culture of Lactobacillus

In this study, the potential use of sweet whey as a base medium for lactic acid bacteria culture and its effect on the technological characteristics of lactobacilli was evaluated. Bacteria were grown on raw or deproteinized whey supplemented with different amounts of yeast extract and/or tomato juice. Results obtained showed that biomass production on whey supplemented with yeast extract was higher than those observed with tomato juice. Whilst, supplementation by either whey, tomato juice or yeast extract increased significantly the growth of both lactic acid bacteria, the performance was in the same range as that on a modified MRS medium. Additionally, acidification and proteolytic activities resulting from control and modified MRS medium were of comparable values. The present investigation demonstrates that sweet whey can be used as an alternative substrate for lactic acid bacteria cultural purposes and provide opportunity to make a new growth medium with low cost.   Key words: Acidification, bacterial growth, Lactobacillus, proteolytic activity, sweet whey, tomato juice, yeast extract.