Strong static magnetic field enhances biomass and high-value lipid production in Chlorella pyrenoidosa via metabolic regulation.

Abstract

trong static magnetic field (SMF) treatment represents a promising physical strategy for regulating microalgal metabolism. This study investigated the effects of SMF on growth and lipid production in Chlorella pyrenoidosa. Results showed that SMF exposure at 3T for 10 min under photoperiodic conditions was optimal, achieving a biomass of 1.25 g/L (a 42% increase over the control). The biomass productivity increased 1.82-fold to 0.31 g/L/d, and the logarithmic growth phase was shortened by 2 days (Δt = 4 d). Lipid content reached 34.4% (1.26-fold of control), and total lipid yield increased 1.60-fold (439.17 mg/L), with the proportion of polyunsaturated fatty acids (PUFA) rising from 70.14% to 74.28%, and α-linolenic acid increasing from 48.45% to 54.12%. SMF induced an increase in reactive oxygen species, which was accompanied by enhanced non-enzymatic antioxidant capacity involving carotenoids, reduced glutathione, and α-tocopherol. Integrated physiological, transcriptomic, and proteomic analyses indicated that short-term SMF treatment was associated with intracellular calcium elevation and proteomic-level enrichment of mitogen-activated protein kinase (MAPK)-related regulatory processes, potentially contributing to cellular metabolic restructuring. SMF promoted photosynthetic light-harvesting capacity, DNA replication and repair-related networks, and motor protein-associated intracellular transport, while reorganizing central carbon metabolism under mixotrophic conditions to potentially favor lipid accumulation. This study highlights the potential of short-term SMF treatment as a strategy for improving microalgal biomass and PUFA-enriched lipid production.