Nutritional requirements and simplified cultivation medium to study growthand energetics of a sourdough lactic acid bacterium Lactobacillus fermentum Ogi E1 during heterolactic fermentation of starch

Aims: Nutritional requirements of Lactobacillus fermentum Ogi E1 were studi ed in order to define a simplified fermentation medium. Methods and Results: When grown with MRS-medium in 21 bioreactors, a biphas ic pattern of growth and metabolite production was observed. Study of nutri tional requirements resulted in a simplified medium (SYAM) that allowed, un der anaerobiosis, similar results to be obtained as in MRS medium, but with out biphasic fermentation kinetics. The best substrates for both growth and amylase production were starch and maltose. Although melibiose, raffinose, fructose, sucrose and glucose also supported growth, lower amylase activit y was observed. Conclusions: The physiology of the strain can be investigated with SYAM med ium, using either starch or maltose as substrate. The strain also presented potential for alpha -galactoside fermentation. Significance and Impact of the Study: Lactobacillus fermentum was one of th e dominant bacteria of African maize dough fermentations. Amylolytic strain s with activity against other compounds (i.e. raffinose) suggested a potent ial to be used as starter for cereal fermentation.