Squalene: A High-Value Compound for COVID-19 Vaccine Adjuvants and Beyond Pathways, Production Strategies, and Market Potential.

Squalene, a naturally occurring triterpene, has gained significant attention due to its critical role as an adjuvant in COVID-19 vaccines and its broad applications in pharmaceuticals, cosmetics, and nutraceuticals. This review explores the potential of squalene production, prompting a shift toward sustainable and innovative approaches. Key biosynthetic pathways across various organisms, including plants, fungi, and microalgae, are analyzed to identify efficient production systems as compared to fast-growing heterotrophic thraustochytrids. Advanced strategies to enhance squalene yields are explored, including the use of chemical enhancers (methyl jasmonate), antioxidants (alpha-tocopherol), cofactor recycling, and squalene epoxidase inhibitors (terbinafine). Additionally, the global market potential of squalene is assessed, highlighting its economic importance and growing demand in the healthcare and cosmetic industries. The challenges of large-scale squalene production are addressed with a focus on sustainable alternatives to shark-derived sources as a high ethical concern. By aligning with Sustainable Development Goals (SDG-3: Good Health and Well-Being), squalene production supports advancements in vaccine development and biotechnological innovations. Future opportunities are highlighted, including novel applications in cancer therapy, functional foods, and anti-aging products, offering pathways to harness its full potential while contributing to a sustainable bioeconomy.