The aim of this study is to optimize the production of Baker's yeast, vinegar, Citric acid, Ethanol and a-amylase using dates of low commercial value as the basal fermentation medium. The results of this study showed that the optimal Baker's yeast production was obtained with a dilution rate of 0.22 h-1. As for the Ethanol production, the optimum yield obtained was 131.0 g/L under optimum conditions of an incubation period of 72 h, inocula content of 4 % (w/v), sugars content of 180.0 g/L and ammonium phosphate content of 1.0 g/L. As for the acetic fermentation, under optimal conditions, temperature of 30 °C, an initial acidity of 1.2 % and an aeration of 2VVM, the productivity of vinegar obtained is 0.0476 g/100 ml/h. Also, the obtained results show that it is possible to obtain by continuous fermentation each 36 h, the vinegar with an acidity ranging between 72.0 to 85.0 g/L. Concerning the Citric acid production, the cumulative effect of temperature (30 °C), methanol content (3 %), initial pH (3.5) and ammonium nitrate concentration (2.5 g/L) during the fermentation process of dates syrup did increase the citric acid production to 97.0 g/L.