Light acclimation across the photobioreactor thickness is key to high biomass production in Picochlorum renovo

In recent years, Picochlorum renovo has emerged as a promising microalgae species due to its rapid growth and high biomass productivity, making it a suitable candidate for large-scale biotechnological applications. Nevertheless, this species remains only partially characterized, and its physiological behavior, adaptive strategies, and industrial potential still require thorough quantitative investigation. Picochlorum renovo was cultivated in chemostat mode under varying incident light intensities and photobioreactor light paths. A remarkable growth and photoconversion efficiency was recorded under light-limited conditions. Consistently, the improved photon absorption capacity appeared to be linked to the peculiar pigment acclimation features of this species to photon scarcity. Indeed, P. renovo preserved both areal biomass productivity (40 g m −2 d −1 ) and photosynthetic efficiency (14% on PAR) and progressively enhanced pigment production (up to 6% of dry weight) across the photobioreactor thickness (up to 15 cm). In compartmentalized reactors, it has shown the capability to adapt to the thickness of the reactor. Efficient pigment acclimation in P. renovo may play a role in its remarkable growth performance and, eventually, highlight its potential for biotechnological applications in compact photobioreactor systems, where efficient photon utilization is crucial for process optimization.