Analysis of population structures of the microalga Acutodesmus obliquus during lipid production using multi-dimensional single-cell analysis

Abstract

Microalgae bear a great potential to produce lipids for biodiesel, feed, or even food applications. To understand the still not well-known single-cell dynamics during lipid production in microalgae, a novel single-cell analytical technology was applied to study a well-established model experiment. Multidimensional single-cell dynamics were investigated with a non-supervised image analysis technique that utilizes data from epi-fluorescence microscopy. Reliability of this technique was successfully proven via reference analysis. The technique developed was used to determine cell size, chlorophyll amount, neutral lipid amount, and deriving properties on a single-cellular level in cultures of the biotechnologically promising alga Acutodesmus obliquus. The results illustrated a high correlation between cell size and chlorophyll amount, but a very low and dynamic correlation between cell size, lipid amount, and lipid density. During growth conditions under nitrogen starvation, cells with low chlorophyll content tend to start the lipid production first and the cell suspension differentiated in two subpopulations with significantly different lipid contents. Such quantitative characterization of single-cell dynamics of lipid synthesizing algae was done for the first time and the potential of such simple technology is highly relevant to other biotechnological applications and to deeper investigate the process of microalgal lipid accumulation.

Influence of Nitrogen Limitation on Lipid Accumulation and EPA and DHA Content in Four Marine Microalgae for Possible Use in Aquafeed

“…The lower lipid content under stronger N-limitation may be due to the improper harvesting time. Lipid per cell reached a maximum at day six and then started to decrease (Sandmann et al, 2018). This indicates that the harvesting of N. oceanica should be done at a time when lipid content is highest.…”

Decay of Trichomes of Arthrospira platensis After Permeabilization Through Pulsed Electric Fields (PEFs) Causes the Release of Phycocyanin

“…One possibility, for example, would be the combination with fluorescence microscopy. This technology allows for better differentiation between smaller cell debris and dirt particles based on the intrinsic fluorescence of pigments such as chlorophyll or PC (Sandmann et al, 2017(Sandmann et al, , 2018. Such a microscopy-based approach for the investigation of single cells would provide information not only on cell size but also on the pigmentation of cells and, thus, their vitality.…”

Establishment of a simple method to evaluate mixing times in a plastic bag photobioreactor using image processing based on freeware tools

“…Proper mixing in reactors is needed, e.g., for optimal mass and heat transfer and to prevent cells settling. Inadequate mixing is the reason for the appearance of spatial gradients in reactors, which is believed to inherently increase cell-to-cell heterogeneity and thus negatively affect the productivity of bioprocesses and product quality [ 2 , 16 – 18 ].…”