Cell Analysis of Algae with Impedance Flow Cytometry for label-free measurements without interference of turbid or autofluorescent media

The often small size of algae cells makes their analysis more challenging compared to other cell types. In addition, autofluorescence in microalgae makes analysis of cell properties and counting even more difficult with optical methods. Amphasys’ Impedance Flow Cytometer is based on electrical properties of cells and is not affected by autofluorescence or the small cell size.  

This allows: 

  • Characterization of phenotypic differences  
  • Measurement of time-resolved cell growth and metabolic activity  
  • Monitoring of stress and identification of stress tolerant algae strains 
  • Monitoring of bioprocess related production of proteins, lipids etc. 

The benefits for algae measurements are: 

  • Simultaneous measurement of cell count and cell viability. 
  • Measurement of metabolic status  
  • Label-free analysis with immediate results  
  • No interference from autofluorescence or turbidity. 

Case study: Fatty Acid Production in Microalgae

Microalgae synthesize all necessary carbohydrates by photosynthetic CO2 assimilation. By changing the culture conditions, microalgae can adapt their metabolism to growth in the dark if alternative carbon sources, e.g., sugar, glycerol, or even carbon containing waste, are provided. 

During the metabolic adaptation process, algae cultures turn from green to white color caused by loss of chloroplasts. In parallel, they generate large oil droplets to store the carbon as fatty acids. These fatty acids can be harvested and processed into other chemicals, like biodiesel. 

With the non-invasive technology of Amphasys the transformation from photosynthetic microalgae to fatty acid producing cells can be monitored in bioreactors without the need for extra labelling, laborious microscopic studies or biochemical assays. 

The diagram shows that in the dark in presence of glucose the population grows faster than in the reference under photosynthetic conditions. The scatterplots show – in addition to the faster growing population in the dark – an increase in amplitude (y-axis) because of a growth in cell volume related to the formation of the fatty acid droplets inside the cells. In light under photosynthetic conditions, without addition of glucose, microalgae grow slower, and the formation of fatty acids doesn’t take place. 

Amphasys Cell Analyzer

The Ampha X30 is Amphasys’ next generation for cell analysis in Bioprocessing. It is tailor made for analyzing a broad range of different cell types like bacteria, mammalian, insect, algae or yeast. The newly designed technological platform enables highly accurate determination of, cell viability, concentration, differentiation, and cell status. This information must be considered in scale-up process during propagation in biofuel, bioplastic, enzyme, pharmaceutical or ethanol production.

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