Palm oil mill effluent, as alternative cultivation media for safe and efficient production of microalgae-derived bioproducts

Palm oil mill effluent (POME) is a nutrient-rich wastewater with high organic content and colloidal matters; its direct discharge poses serious threats to both soil and aquatic ecosystems. However, the pollutant from POME can potentially be used as nutrient sources for microalgae production. The existing organic substances in POME that can be converted into bioavailable carbon, enhancing its compatibility for mixotrophic or heterotrophic microalgal growth. Certain microalgae exhibit resilience and adaptability to grow in POME, utilizing the carbon and nutrient content to synthesize high-value bioproducts. This review reports the feasibility of POME as an alternative cultivation medium, recent advancements in enhancing microalgal productivity, and the diverse bioproducts generated, including lipid biofuels, bioplastics, and other biomass-derived bioenergy. The impact of physicochemical characteristics of POME towards the cultivation and microalgae-derived bioproducts are also compared. This paper also highlights major challenges in POME-grown microalgae, including the reliance on targeted nutrient supplementation despite nutrient abundance, the high cost of downstream bioproduct recovery, and limited knowledge in the regulatory framework and safety compliance of wastewater-grown microalgae. Potential future research focus includes the utilization of organic nutrients in POME to enhance nutrient recycling efficiency and maximize the production of cost-effective biomass that aligns with industrial standards. • Palm oil mill effluent (POME) is a potential nutrient-rich media for microalgae. • POME-based medium supports mixotrophic and heterotrophic microalgae. • The recent applications of POME-grown microalgae were discussed. • The safety of POME-grown microalgae was assessed for high-value applications.