Recent Advances in Fungal β-Carotene Production: Signalling, Metabolic Engineering, and Bioprocess Development

Abstract

β-Carotene (C40H₅₆) is one of the most commercially important carotenoids owing to its provitamin A activity, antioxidant properties, and extensive applications in food, feed, nutraceutical, pharmaceutical, and cosmetic industries. Growing consumer demand for naturally derived pigments has intensified interest in microbial fermentation as a sustainable alternative to petrochemical synthesis. Among microbial producers, the heterothallic zygomycete Blakeslea trispora remains the dominant industrial platform due to its exceptional β-carotene biosynthetic capacity, efficient submerged fermentation performance, and unique trisporic acid-mediated mating-type signalling system that strongly enhances carotenogenesis.
This review critically examines recent advances in the biology, metabolism, and industrial exploitation of B. trispora for β-carotene production. The taxonomy, morphology, heterothallic life cycle, and trisporic acid signalling network are discussed in relation to carotenoid biosynthesis. Particular emphasis is placed on the complete mevalonate pathway from acetyl-CoA to β-carotene, highlighting key regulatory enzymes including HMG-CoA reductase (hmgR), isopentenyl pyrophosphate isomerase (ipi), geranylgeranyl pyrophosphate synthase (carG), phytoene synthase/lycopene cyclase (carRA), and phytoene desaturase (carB). Advances in fermentation technology, including fed-batch cultivation, oxygen management, lipid supplementation, and process optimisation strategies, are evaluated alongside downstream recovery and purification approaches. The review further analyses recent progress in strain improvement through classical mutagenesis, metabolic engineering, systems biology, and emerging genome-editing technologies. Emerging research directions involving CRISPR-based metabolic engineering, multi-omics-guided strain design, artificial intelligence-assisted bioprocess optimisation, agro-industrial waste valorisation, process analytical technologies, and nanoencapsulation-based formulation systems are also explored.

Keywords