Natural Carotenoids: Recent Advances on Separation from Microbial Biomass and Methods of Analysis

Abstract

Biotechnologically produced carotenoids occupy an important place in the scientific research. Owing to their role as natural pigments and their high antioxidant properties, microbial carotenoids have been proposed as alternatives to their synthetic counterparts. To this end, many studies are focusing on their efficient and sustainable production from renewable substrates. Besides the development of an efficient upstream process, their separation and purification as well as their analysis from the microbial biomass confers another important aspect. Currently, the use of organic solvents constitutes the main extraction process; however, environmental concerns along with potential toxicity towards human health necessitate the employment of “greener” techniques. Hence, many research groups are focusing on applying emerging technologies such as ultrasounds, microwaves, ionic liquids or eutectic solvents for the separation of carotenoids from microbial cells. This review aims to summarize the progress on both the biotechnological production of carotenoids and the methods for their effective extraction. In the framework of circular economy and sustainability, the focus is given on green recovery methods targeting high-value applications such as novel functional foods and pharmaceuticals. Finally, methods for carotenoids identification and quantification are also discussed in order to create a roadmap for successful carotenoids analysis.

Current Advances in Carotenoid Production by Rhodotorula sp.

“…It uses various economical and renewable substrates, such as lignocellulosic hydrolysates, organic industrial waste, and vegetable mandi waste. It has optimal growth at low pH, which makes it possible to reduce bacterial growth [1]. However, it is crucial to consider certain factors that can significantly influence the fermentation process (Figure 3).…”

“…Carotenoids are a group of compounds extensively used in the chemical, pharmaceutical, and food industries. Their market size has been expanding, from 1.5 billion in 2019 to 2.0 billion dollars in 2026, at a rate of 4.2% per year [1]. Carotenoids, a precursor of vitamin A, can enhance immune response, and they have antioxidant capacity because they can scavenge oxygen radicals [2].…”

Algal Carotenoids: Chemistry, Sources, and Application

“…In line with the principles of environmentally friendly extraction, extraction processes have recently been developed that minimize the use of organic solvents, utilize renewable resources, and also ensure a high content of extracted compounds and their quality. Various methods have been developed for the rapid and efficient extraction of carotenoids from algae, usually combined with cell disruption to facilitate the release of carotenoid pigments [16][17][18][19]. Strategies involving mechanical disruption followed by solvent extraction have increased the yield of extracted carotenoid compounds [20][21][22].…”

“…[11,12,17,[25][26][27][28][29]. Recent reviews [16,18,20,[30][31][32][33] compared the different conventional and novel methods for the extraction of carotenoids from algae, such as physical, chemical, mechanical (grinding, milling, pressure), microwave-assisted extraction, ultrasound-assisted extraction, enzymatic hydrolysis, application of electric fields, ionic liquids, deep eutectic solvents, chemical solvation, extraction with supercritical fluids, etc.…”

Recent Advances in the Carotenoids Added to Food Packaging Films: A Review

“…These pigments have a high chemical reactivity due to a conjugated system of double bonds, rendering them susceptible to simple isomerization and oxidation reactions. [47].…”