New biotechnological routes to upcycle food by-products and waste into high-value lipids through microalgae

The increasing demand for sustainable sources of long chain polyunsaturated fatty acids (PUFAs), such as DHA and EPA, has driven research into alternative production methods. This review explores the potential of using FBW and by-products as substrates for microalgae cultivation, offering a cost-effective and environmentally friendly approach to PUFA production. Through a structured narrative and a deep bibliometric analysis, key trends and research hotspots were identified, highlighting the most promising microalgae and thraustochytrids species, including Aurantiochytrium sp., Phaeodactylum tricornutum, and Nannochloropsis oculata. These species demonstrated high lipid yields and significant PUFA content when grown on diverse FBW substrates, such as dairy by-products, molasses, and palm oil mill effluent. The review emphasizes the importance of pretreatment processes of recycled nutrients, such as enzymatic hydrolysis and fermentation, in enhancing nutrient bioavailability and optimizing microalgal growth. Economically, the use of FBW can reduce operating costs with potential increases in return on investment. However, challenges such as the initial setup costs of pretreatment processes and the need for contamination control must be addressed. To assist investors, a decision tree was developed, guiding through critical decision points, from resource assessment to process optimization and economic analysis. This tool supports informed decision-making, ensuring the balance of costs, benefits, and sustainability goals.