Optimization of culture medium for submerged cultivation of Mycolicibacterium neoaurum AC-3067D – a beta-carotene producing strain

The replacement of glucose with glycerol has demonstrated the most significant influence on beta-carotene biosynthesis using Mycolicibacterium neoaurum AC-3067D. However, from a technological standpoint, residual glycerol hinders the drying of biomass, which can be used to produce feed additives for poultry and livestock. This study aims to determine the optimal concentrations of glycerol, glucose, and Tween 80 using a 23 full factorial experiment, along with testing an optimized medium during the deep cultivation of Mycolicibacterium neoaurum in a 3L bioreactor. We evaluated the accumulation of Mycolicibacterium neoaurum biomass and beta-carotene content in response to the replacement of 20 g/L glycerol with a combination of 10 g/L glycerol and 10 g/L glucose. The results demonstrated comparable productivity of the strain between the modified and control media, yielding 17.8 g/L biomass and 182.5 mg/kg beta-carotene. The study showed that the incorporation of Tween 80 (1 g/L) into the nutrient medium resulted in a 14.0% and 32.2% increase in biomass and beta-carotene yield, respectively, in comparison to the control. The medium, optimized using a 2 3 full factorial experiment, contained glycerol (15.0 g/L), glucose (5.0 g/L), and Tween 80 (1.5 g/L). The cultivation of Mycolicibacterium neoaurum in a bioreactor using this growth medium resulted in a maximum productivity of 376.5 mg/kg of beta-carotene and 25.2 g/L of biomass.

carotenoids, Mycolicibacterium neoaurum, biosynthesis, cultivation, bioreactor