Repeated nitrogen starvation doesn't affect lipid productivity of Chlorococcum littorale

Abstract

In the present work we wanted to know what happens during time to biomass and lipid productivities of Chlorococcum littorale repeatedly subjected to N-starvation. Experiments were done using repeated cycles of batch-wise N run-out (after 2days N=0). Two different cycles were used: repeated short-starvation (6days of N=0) over a total period of 72days and repeated long-starvation (13days of N=0) over a total period of 75days. Batches (using fresh inocula) were done separately as control. Shorter and longer periods of starvation showed no differences in biomass productivities and PSII quantum yield evolution. The repeated short-starvation-batches showed the same lipid productivities as the control short-starvation batches. Most importantly, the biomass lipid content was the same between control and repeated-batches. Altogether, the results point to C. littorale as a resilient and stable strain, with potential to be used under semi continuous cultivation.

Keywords: Adaptive laboratory evolution (ALE); Chlorococcum littorale; Microalgae; Nitrogen-starvation; Repeated-batch.