Continuous versus batch production of lipids in the microalgae Acutodesmus obliquus

This work provides a novel quantitative comparison of batch versus continuous microalgal lipid production in the wild type and starchless mutant strain of Acutodesmus obliquus. Both strains showed higher TAG yields on light under batch operation compared to continuous nitrogen limitation. The starchless mutant showed 0.20gTAGmolph -1 for batch and 0.12gTAGmolph -1 for continuous operation, while the wildtype only showed 0.16gTAGmolph -1 for batch and 0.08gTAGmolph -1 for continuous operation. Also, higher TAG contents were found under batch starvation (26% of dry weight for the wildtype and 43% of dry weight for starchless mutant) compared to continuous cultivations (16% of dry weight for the wildtype and 33% of dry weight for starchless mutant). Starch acts as the favoured storage metabolite during nitrogen limitation in A. obliquus, whereas TAG is only accumulated after starch reaches a cellular maximum of 40% of dry weight.