Tailor-made solvents for microbial carotenoids recovery

Abstract

In recent years, microbial carotenoids have emerged as a promising alternative for the pharmaceutical and food industries, particularly in promoting human health due to their potent antioxidant and antimicrobial properties. Microbial carotenoids, particularly those produced by yeast, bacteria, and microalgae, are synthesized intracellularly, requiring the use of solvents for their effective extraction and recovery. The conventional use of toxic volatile organic solvents (VOCs) like hexane, petroleum ether, and dimethyl sulfoxide in the extraction of microbial carotenoids has been common. However, ongoing research is introducing innovative, non-toxic, environmentally friendly tailor-made solvents, such as ionic liquids (IL) and deep eutectic solvents (DES), indicating a new era of cleaner and biocompatible technologies. This review aims to highlight recent advancements in utilizing IL and DES for obtaining carotenoids from microorganisms. Additionally, we explore the utilization of in silico tools designed to determine the solubilities of microbial carotenoids in tailor-made DES and ILs. This presents a promising alternative for the scientific community, potentially reducing the need for extensive experimental screening of solvents for the recovery of microbial carotenoids in the separation processing. According to our expert perspective, both IL and DES exhibit a plethora of exceptional attributes for the recovery of microbial carotenoids. Nevertheless, the current employment of these solvents for recovery of carotenoids is restricted to scientific exploration, as their feasibility for practical application in industrial settings has yet to be conclusively demonstrated. KEY POINTS: • ILs and DES share many tailoring properties for the recovery of microbial carotenoids • The use of ILs and DES for microbial carotenoid extraction remains driven by scientific curiosity. • The economic feasibility of ILs and DES is yet to be demonstrated in industrial applications.

Keywords: Alternative solvents; Carotenoids; Deep eutectic solvents; Ionic liquids; Microorganisms.