Utilization of Date Juice for the Production of Lactic Acid by Streptococcus Thermophilus

Abstract

The interest in the fermentative production of lactic acid has increased due to the prospects of environmental friendliness and of using renewable resources instead of petrochemicals. In this context, we have judged that is gainful to use the date juice which is with a low commercial value as a substrate for the production of lactic acid by Streptococcus thermophilus. Further, dates are rich in sugar ranging from 65% to 80% on dry weight basis mostly of inverted form (glucose and fructose), which can used as carbon source for the fermentation and the production of microbial biomass. The parameters optimization for lactic acid production by S. thermophilus grown on medium based on dates in order to improve yields is applied in this study. The results showed that the maximum of lactic acid production (36.9g/l) is obtained after the enrichment of date juice with yeast extract (15%), Tween 80 (1g/l) MgSO4 (0.5g/l), MnSO4 (0.02g/l) and K2HPO4 (1g/l).