Cultivation responses of the extremotolerant green alga Pseudococcomyxa simplex PSSC23 (Trebouxiophyceae, Chlorophyta) under various cultivation conditions: growth and photosynthetic pigment profiles
摘要
Pseudococcomyxa simplex PSSC23 is an extremotolerant green microalga characterized by its extensive ecological adaptability, rendering it a promising candidate for biotechnological applications. In this study, we systematically evaluated the physiological and biochemical responses of P. simplex PSSC23 to various environmental gradients, including temperature (10–35 °C), irradiance (19.1–79.9 μmol photons m⁻2 s⁻1), salinity (0–40 ppt), and pH (2–10) in 10-day batch cultures conducted in triplicate and sampled every 24 h. The strain was identified by 18S rDNA and rbcL sequencing, with confirmation provided by phylogenetic analyses. Optimal growth occurred at 24 °C and ~ 44 μmol photons m⁻2 s⁻1, with measurable tolerance across sub-optimal salinity and pH ranges. Lutein was identified as the predominant carotenoid, accounting for over 60% of the total carotenoid content. Its intracellular concentration was observed to increase under acidic conditions and saline environments; however, this increase was associated with a reduction in yield. Collectively, the extensive and established capabilities of the strain P. simplex PSSC23 position it as a versatile microalgal chassis suitable for outdoor cultivation and integrated biorefineries. These systems can effectively combine production with concurrent wastewater treatment and recovery.