Multispectral imaging flow cytometry for process monitoring in microalgae biotechnology

Abstract

In the course of efficient development and optimization of biotechnological processes, the need for methods to track morphological and compositional changes of single cells is increasing. So far, the material composition of cells is determined by chemical analysis of a pooled cell sample, which reflects the average composition of the taken cell collection. Conventional flow cytometry enables the analysis of individuals from a population. However, it cannot resolve such valuable information like morphological details and distribution of molecular compounds inside the cells. This gap is bridged by a combination of imaging flow cytometry and multispectral imaging. The potential of this Multispectral Imaging Flow Cytometry (MIFC) approach has been investigated and confirmed in the presented parameter study on the bioproduction of Astaxanthin (Ax) by the microalgae Haematococcus pluvialis (HP). As far as multispectral imaging in transmission mode, only three spectral channels (446 nm, 532 nm, 646 nm) were used to measure the amount of substance and the molecular distribution of the core components chlorophyll (Chl) and Ax. Both could be clearly separated from the phase-contrast information generated from the cellular structures and morphology. In general, the results from the MIFC method comply with the conventional measurements but extend them for details on the morphology and on compositional changes within the cultivated cell population during the cultivation process and in response to the applied stimuli.

Keywords

• Multispectral imaging flow cytometry
• Multispectral
• Algae
• Process monitoring
• Chemometrics
• Biotechnology