In vivo kinetics of lipids and astaxanthin evolution in Haematococcus pluvialis mutant under 15% CO2 using Raman microspectroscopy

Abstract

In vivo spatiotemporal dynamics of lipids and astaxanthin evolution in Haematococcus pluvialis mutant induced with 15% CO₂ and high light intensity were monitored with high spatial resolution in a non-destructive and label-free manner using single-cell Raman imaging. Astaxanthin intensity increased by 3.5 times within 12h under 15% CO₂, and the accumulation rate was 5.8 times higher than that under air. Lipids intensity under 15% CO₂ was 27% higher than that under air. The lipids initially concentrated in chloroplast under 15% CO₂ due to an increase of directly photosynthetic fatty acid, which was different from the whole-cell dispersed lipids under air. Astaxanthin produced in chloroplast first accumulated around nucleus and then spread in cytoplasmic lipids under both air and 15% CO₂. The calculation results of kinetic models for lipids and astaxanthin evolutions showed that accumulation rate of lipids was much higher than that of astaxanthin in cells.

Keywords: Astaxanthin; Haematococcus pluvialis; Kinetics; Lipids; Raman microspectroscopy.