par Ras El Gherab, Fatma Zohra;Alsayed Mahmoud, Kassem ;Hassaine, Omar;Zadi-Karam, Halima;Karam, Nour-Eddine;Hiligsmann, Serge
Référence 7th International Conference on Engineering for Waste and Biomass Valorisation (2-5 july: Prague - Czech Republic)
Publication Non publié, 2018-07-02
Communication à un colloque
Résumé : The Algerian palm production represents an important pivot for oasis ecosystem. Approximately, 18 million date palm trees are cultivated on a surface of 169.380 ha. Consequently, Algeria is one of the highest date fruit producers with about 500 000 tons yearly commercialized worldwide. However the date-processing companies also generates large amounts of sugar-rich wastes e.g. from damaged fruits. For the last years, attention has been paid on sustainable management of these wastes and on their valorization with the aim of developing the organic matter recycling. Therefore, the objectives of our PhD investigations were to optimize a new culture medium containing date juice for the growth of Lactococcus lactis. This work is a contribution to the valorization of date waste for the production of lactic acid at industrial scale. Cultures in batch and fed-batch mode were carried out with different controlled pH in a Sartorius 2L and 15L stirred bioreactors with optical density (Fundalux probe) and added base monitoring.The results obtained showed that Lactococcus lactis growth and acid production were not significantly affected with a pH ranging between 5.8 and 7. In batch culture at pH 7, the reducing sugars from date juice at an initial concentration of 14 g/l in the culture medium led to 10.9 g/l of final concentration of lactate. Prolongation of the culture in fed-batch mode with the addition of a similar sugar content led to maintain a similar yield of lactate with concentration of 20 g/l. Similarly, lactic acid productivity remains stable with 0.66 g/l/h and 0.62 g/l/h for cultures in mode batch and fed-batch, respectively. However, no further growth was achieved as measured by the OD probe and by classical UFC or OD methods in samples.