Effect of high hydrostatic pressure on extraction of B-phycoerythrin from Porphyridium cruentum: Use of confocal microscopy and image processing

The aim of the study was to extract B-phycoerythrin from Porphyridium cruentum while preserving its structure. The high hydrostatic pressure treatments were chosen as extraction technology. Different methods have been used to observe the effects of the treatment: spectrophotometry and confocal laser scanning microscopy followed by image processing analysis. Image processing led to the generation of masks used for the identification of three clusters: intra, extra and intercellular. All methods showed that high hydrostatic pressure treatments between 50 and 500 MPa failed to extract B-phycoerythrin from Porphyridium cruentum cells. The fluorescence emission was negatively impacted by high hydrostatic pressure treatment from 400 MPa for the extracellular and intercellular cluster and from 500 MPa for the intercellular cluster. These results suggest that high pressure treatments could induce the denaturation of B-phycoerythrin in all clusters but with different intensities depending on the cluster. [Display omitted] •5 min at 500 MPa treatment had no effect on cell morphology.•Extra and intercellular clusters showed fluorescence decrease from 400 MPa.•Intracellular cluster showed fluorescence decrease from 500 MPa.•Intracellular cluster may play a protective effect towards B-phycoerythrin.