Scale translation from shaken to diffused bubble aerated systems for lycopene production by Blakeslea trispora under stimulated conditions

This study deals with the scale up of Blakeslea trispora culture from the successful surface-aerated shake flasks to dispersed-bubble aerated column reactor for lycopene production in the presence of lycopene cyclase inhibitor 2-methyl imidazole. Controlling the initial volumetric oxygen mass transfer coefficient (k_La) via airflow rate contributes to increasing cell mass and lycopene accumulation. Inhibitor effectiveness seems to decrease in conditions of high cell mass. Optimization of crude soybean oil (CSO), airflow rate, and 2-methyl imidazole was arranged according to central composite statistical design. The optimized levels of factors were 110.5 g/L, 2.3 vvm, and 29.5 mg/L, respectively. At this optimum setting, maximum lycopene yield (256 mg/L) was comparable or even higher to those reported in shake flasks and stirred tank reactor. 2-Methyl imidazole use at levels significantly lower than those reported for other inhibitors in the literature was successful in terms of process selectivity. CSO provides economic benefits to the process through its ability to stimulate lycopene synthesis, as an inexpensive carbon source and oxygen vector at the same time.