Endophyte-Mediated Limonene Production: A Sustainable Frontier for Pharmaceutical Applications

Limonene (a monoterpene) is well known for its medicinal relevance and versatile pharmaceutical applications. It is widely used in household products, cosmetics, agriculture, pharmaceuticals and as a flavoring agent in food. Additionally, limonene exhibits strong anti-inflammatory, antioxidant, anticancer and antimicrobial properties. These biological activities support its potential role in management of cardiovascular and respiratory and other complications. Traditionally, limonene has been obtained from Citrus sources on an industrial level; however, several studies have reported multiple endophytes as efficient, environmentally friendly and alternative source for limonene production. Moreover, microbial biosynthesis has also emerged as a sustainable strategy for limonene production, leveraging genetically engineered microorganisms like E. coli and S. cerevisiae . These endophytes provide a renewable source of limonene for industrial use and their presence can also be beneficial in improving biological activities because of their potential to engage in biotransformation. Furthermore, these endophytes show enhanced efficiency over conventional plant extraction, yielding limonene along with other valuable metabolites. Studies highlight significant biological applications (antioxidant, antibacterial and pesticidal potential) of endophyte-derived limonene. Due to various therapeutic and pharmaceutical benefits of limonene, this review emphasizes the role of endophytes as an alternative source for limonene. Here, we have reviewed and proposed new ways to improve the process of limonene production and limonene’s performance in terms of bioactivity, thereby allowing its use in a broader number of processes within the pharmaceutical industry.