Optimization of Total Carotenoid Production by Rhodotorula mucilaginosa from Artichoke Agroindustrial Waste Using Response Surface Methodology

Abstract

The carotenoids have vast medical, industrial, dietary, and pharmaceutical importance due to their provitamin A precursor, immunomodulator, antioxidant and photoprotective activity. The purpose of the research was to optimize the production of carotenoids using Rhodotorula mucilaginosa from artichoke agroindustrial waste as a low-cost substrate. The artichokes bracts waste was bleached by sodium hypochlorite (NaClO 2%) and was characterized through whiteness index and FTIR. The bleached artichoke waste (BABW) used in the fermentation went through acid hydrolysis, applying 8% of the bleached artichokes residue and sulfuric acid (2.5%) for 1 h at 90°C, obtaining a greater reduced sugars content at 3.1 g/L. Rhodotorula mucilaginosa was isolated and molecularly identified. The production of carotenoids from a culture media based on hydrolyzed BABW, peptone (0.5%), yeast extract (0.1%) and sodium chloride (0.5%) was evaluated at different conditions of pH (5–8) and agitation speed (80–160 rpm) applying the surface response methodology by a rotational central compound design. The best carotenoids performance obtained had 2968.95 µg/L VVC and 1228.53 µg/g TFC at pH 5, 120 rpm and 30°C for 72 h. The chemical characterization of the extracted carotenoids was confirmed by UV-VIS and Raman spectroscopy methods. The results suggest that Rhodotorula mucilaginosa is capable of producing carotenoids from artichoke waste fermentation, providing a low-cost and sustainable alternative route for use in the global market.