Enhanced production of Bacopa saponins by repeated batch strategy in bioreactor.

Abstract

Cultivation of cell suspension culture of Bacopa monnieri targeting the production of bacosides was explored in a 5-l stirred tank reactor using statistically optimized conditions. The bioreactor cultivation conditions were modified and this led to profuse biomass growth (2.81 ± 0.20g/l) and total bacosides (1.26 ± 0.23mg/g in cells and 0.60 ± 0.11mg/l in fermenter broth) production in 9days. The values of static volumetric mass transfer coefficient (kLa), dimensionless mixing time (Nm) were measured in the bioreactor. The culture grew efficiently and produced enhanced amount of bacoside A (5.59 ± 0.41mg/g total bacosides in cells and 3.12 ± 0.13mg/l in the fermenter broth) using one cycle of repeated batch strategy adopted in the bioreactor for 15days. The intracellular concentration of bacoside A3 (1.18 ± 0.11mg/g), bacopaside II (2.09 ± 0.35mg/g), bacopaside X (0.79 ± 0.17mg/g) and bacopasaponin C (2.24 ± 0.23mg/g) were significantly higher in repeated batch as compared to batch bioreactor cultivation. The yield of total bacosides in the fermenter broth was 5-times higher in repeated batch as compared to batch cultivation. This strategy can be helpful for the enhanced production of other valuable triterpenoid saponins.