Succinic acid production from Bacteroides fragilis: Process optimization and scale up in a bioreactor

We report the effect of different physiological and nutritional parameters on succinic acid production from Bacteroides fragilis. This strain initially produced 0.70 g L−1 of succinic acid in 60 h. However, when process optimization was employed, 5.4 g L−1 of succinic acid was produced in medium consisting of glucose (1.5%); tryptone (2.5%); Na2CO3 (1.5%), at pH 7.0, when inoculated with 4% inoculum and incubated at 37 °C, 100 rpm for 48 h. A marked enhancement in succinic acid production was observed when the optimized conditions were employed in a 10 L bioreactor. A total of 12.5 g L−1 of succinic acid was produced in 30 h. This is approximately 12-fold increase in succinic acid production when compared to the initial un-optimized medium production. This enhancement in succinic acid production may be due to the control of CO2 supply and the impeller speed. This is also resulted in the reduction of the production time. The present study provides useful information to the industrialists seeking environmentally benign technology for the production of bulk biomolecules through manipulation of various chemical parameters.