Phytohormone-Assisted Bioprocess Engineering for Enhanced Omega Fatty Acid Production in Marine Thraustochytrids...

Microbial platforms are now recognized as sustainable sources of long-chain polyunsaturated fatty acids (PUFAs). This study presents a novel bioprocessing approach that integrates abiotic stress with exogenous phytohormones, indole-3-acetic acid (IAA), salicylic acid (SA), and abscisic acid (ABA) to enhance the biosynthesis of PUFAs in marine Thraustochytrium sp. BM2. While individual stress strategies are known to either enhance lipid accumulation or modulate oxidative responses. The combined effect of phytohormones and multiple treatments of cold stress conditions (4 °C) enhanced the PUFAs fraction (including DHA, EPA, DPA, and ARA) and lowered the SFAs fraction. IAA combined with cold stress marginally enhanced lipid yield by 73.3% (up to 9.48 g L⁻¹), but the composition of fatty acids was significantly changed. These changes were aligned with significant increases in EPA (100%, 0.38 g L⁻¹), DPA (19%, 1.06 g L⁻¹), and DHA (19%, 1.94 g L⁻¹). SA in combination with cold stress achieved a 39.7% increase in lipid yield (7.63 g L⁻¹), with corresponding improvements in EPA (21%, 0.23 g L⁻¹), DHA (5.2%, 1.72 g L⁻¹), while ARA (300%, 0.12 g L⁻¹). The combined effect of ABA resulted in enhanced levels of EPA, DPA, DHA, and ARA by 21%, 39%, 16%, and 200%, respectively. These results were statistically validated by ANOVA, with all variations demonstrating significance at p < 0.05. This sustainable and eco-efficient strategy addresses the limitations of fish oil-based PUFA production, aligning with the United Nations Sustainable Development Goals (SDGs: 7, 12, and 13) and offering a scalable alternative for the nutraceutical and biofuel industries.