This work is aimed at evaluating the sustainable extraction of carotenoids from the yeast Rhodotorula glutinis , comparing the effect of ultrasound‐assisted extraction (UAE) and microwave‐assisted extraction (MAE), respectively. The extraction process was optimized using a 2 2 central composite rotatable design (CCRD). In addition, a kinetic study was carried out in the region of the highest yield. The antioxidant activity of the extracts in the optimized condition. Additionally, a sustainability assessment was performed in comparison to conventional extractions. The region of highest carotenoid yield for UAE was > 450 W, 45–55 v/w solvent:biomass ratio, while for MAE, it was 200–350 W, > 65 v/w solvent:biomass ratio. A maximum yield of 76.60% (31.78 μ g β ‐carotene/g bm) was observed for UAE and 42.21% (17.51 μ g β ‐carotene/g bm) for MAE. The kinetic tests showed that after 6.4 min for UAE and 4.8 min for MAE, the extraction process reaches the diffusion period (extraction rate = 0). The results showed that UAE and MAE exerted different effects on the yeast cell disruption. Moreover, MAE promotes thermal degradation, while UAE induces an isomerization phenomenon that led to differences in the carotenoid profiles. Extraction by maceration with ethyl acetate/methanol showed the highest antioxidant activity. Thus, the UAE proved to be an efficient green method in recovering carotenoids produced by R. glutinis . Both techniques were considered sustainable for the metrics evaluated in the study, mainly due to the reduction in extraction time and the nonuse of toxic solvents.
Maia et al. (Thu,) studied this question.