Comparison of Cellular Autofluorescence Patterns of Two Model Microalgae by Flow Cytometry

Abstract

Microalgae are widely used in biotechnological research, especially for the production of biochemical compounds, antioxidants, secondary metabolites, pigments, carbohydrates, proteins and lipids. Various analytical methods are needed throughout both experimental and downstream processing of industrial microalgae products. As one of these methods, flow cytometry is an advantageous option for detecting fluorescently labeled recombinant proteins, lipids and metabolic compounds. It is important to take into account the autofluorescent properties of specific compartments of target cells to well establish a distinct labeling protocol during such analytical processes. Because the amount of autofluorescence may interfere with the fluorescent signal detection of specifically labeled protein or lipid content, this can prevent the precise signal detection of labeled molecules. Furthermore, it can lead to an overestimation of the amount of labeled compounds in the cells. In this study, the autofluorescent properties of two freshwater model microalgae Chlamydomonas reinhardtii (CC-124) and Chlorella vulgaris (CV-898), both of which are predominantly used in industry, were examined by flow cytometry measurements. The experimental findings revealed that fluorescent channel-2 (FL2-H) stands as the most suitable channel to achieve minimal autofluorescence of both CC-124 and CV-898 microalgae strains. The obtained results highlight that one should pay attention to the autofluorescence signals in CC-124 and CV-898 cell lines during the flow cytometry-based detection of biological products when deciding on fluorophore.