Agro-industrial wastes for the synthesis of carotenoids by Xanthophyllomyces dendrorhous: Mesquite pods-based medium design and optimization

Utilization of agro-industrial wastes as cheap nutrient sources for the microbial production of added-value compounds in combination with a statistical approach integrated into earlier process development is a route to ensure a competitive and sustainable bioprocess. In this context, a wastes-based medium was designed and optimized for the biotechnological production of carotenoids by Xanthophyllomyces dendrorhous. The work involved different stages such as waste screening (corncob, cotton husk, mesquite pods, corn steep liquor, residual brewery yeast, and urea), optimization of medium components (Taguchi method), data analysis, and validation of optimum settings. Mesquite pods and corn steep liquor were the selected wastes. The relative influence of factors and individual effects of media components were identified. Mesquite extract was the factor with the highest influence on the total production of carotenoids, while corn steep liquor impacted the yield (carotenoids/biomass). A strategy to define the possible impact of interactions among factors (main disadvantage of saturated designs) was proposed and it was demonstrated that the process performance can be improved with minimum experimental requirements. Optimum designed medium contained (g/L), mesquite pods extract (20), corn steep liquor (3) and yeast extract (3) which allowed to surpass by 40% the carotenoids production using the control medium.