Comparative analysis of isoprostanoid profiles in Chlorella sorokiniana grown under autotrophic and heterotrophic conditions

Oxylipins are bioactive lipid mediators derived from polyunsaturated fatty acids (PUFAs), with roles in oxidative stress responses, immunomodulation, and inflammation. While microalgae are recognized as valuable sources of oxylipins, their profiles remain less studied across different species and cultivation conditions. In this study, we characterized the non-enzymatic oxylipin profile of Chlorella sorokiniana grown under autotrophic and heterotrophic conditions to assess the influence of cultivation strategies on their production. A total of 22 isoprostanoids, mainly Phytoprostanes (PhytoP), Phytofurans (PhytoF), Isoprostanes (IsoP), and Neuroprostanes (NeuroP). Autotrophic cultivation resulted in a higher accumulation of isoprostanoids, particularly the alpha-linolenic acid (ALA) derivatives, PhytoP and PhytoF species, likely due to oxidative stress induced by fluctuating light and temperature conditions. In contrast, heterotrophic growth, performed under controlled conditions, yielded lower overall oxylipin levels highlighting the presence of 10(R)-10-F4t-NeuroP which was only present in heterotrophic Chlorella. We observed a correlation between the PUFA composition of Chlorella and its non-enzymatic oxylipin profile. Notably, several oxylipins identified in Chlorella have been associated with antiinflammatory, immunomodulatory, and neuroprotective properties, emphasizing the potential of this micro-alga as a source of high-value bioactive oxylipins. This study paves the way to the utilization of Chlorella as a source of bioactive oxylipins, as well as to develop cultivation strategies to enhance the production of these lipid mediators.