Production kinetics and characterization of natural food color (torularhodin) with antimicrobial potential

Abstract

The present investigation was conducted to optimize the fermentative production of food color (carotenoid pigments) using Rhodotorula sp. grown under batch cultivation. The effect of different carbon sources, nitrogen source and pH on carotenoid yield was investigated initially. The maximum carotenoid yield of 3520.23 and 2992.65 μg/g were obtained using sorbitol and beef extract as potential carbon and nitrogen sources, respectively, at pH 7.0. Further, process optimization was done using RSM to enhance the carotenoid yield. The optimized condition comprised; 2.0 g/L sorbitol, 0.32 g/L beef extract and 6.25 pH. Optimized condition scale-up in 7.5 L bioreactor (working volume 3.0 L) gave maximum carotenoid and biomass yield of 7325.70 ± 0.04 μg/g and 0.589 ± 0.05 g/L, respectively, after 48 h of cultivation. Leudking Piret model deduced mixed growth associated carotenoid production. The carotenoid pigment was characterized as torularhodin by FTIR and showed antimicrobial activities against E. coli and S. aureus.