title: Structural changes of Arthrospira sp. after low energy sonication treatment for microalgae harvesting: Elucidating key parameters to detect the rupture of gas vesicles.
abstract: The buoyancy suppression by low energy sonication (LES) treatment (0.8W·mL-1, 20kHz, 10s) has recently been proposed as an initial harvesting step for Arthrospira sp. This paper aims to describe the structural changes in Arthrospira sp. after LES treatment and to present how these structural changes affect the results obtained by different analytical techniques. Transmission electron microscopy (TEM) micrographs of trichomes evidenced the gas vesicles rupture but also revealed a rearrangement of thylakoids and more visible phycobilisomes were observed. Differences between treated and untreated samples were detected by confocal microscopy, flow cytometry and optical microscopy but not by electrical impedance spectroscopy (EIS). After LES treatment, 2-fold increase in autofluorescence at 610/660nm was measured (phycocyanin/allophycocyanin emission wavelengths) and a ten-fold decrease in side scatter light intensity (due to a reduction of trichome's inner complexity). This was further confirmed by optical microscopy showing changes on trichomes appearance (from wrinkled to smooth).
authors: Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain. Electronic address: marti.lecina@gmail.com.
authors: Martí
authors: M
authors: Lecina
authors: Electronic and Biomedical Instrumentation Group, Department of Electronic Engineering, Universitat Politècnica de Catalunya (UPC), Campus Nord, C-4, C/ Jordi Girona 1-3, 08034 Barcelona, Spain.
authors: Benjamin
authors: B
authors: Sanchez
authors: Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors: Carles
authors: C
authors: Solà
authors: Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors: Jordi
authors: J
authors: Prat
authors: Servei de Microscòpia, Universitat Autònoma de Barcelona, Edifici C, Facultat de Ciències, 08193 Bellaterra, Spain.
authors: Mònica
authors: M
authors: Roldán
authors: Dep. Productes Naturals, Biologia Vegetal i Edafologia, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
authors: Mariona
authors: M
authors: Hernández
authors: Electronic and Biomedical Instrumentation Group, Department of Electronic Engineering, Universitat Politècnica de Catalunya (UPC), Campus Nord, C-4, C/ Jordi Girona 1-3, 08034 Barcelona, Spain.
authors: Ramon
authors: R
authors: Bragós
authors: Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors: Carlos J
authors: CJ
authors: Paredes
authors: Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors: Jordi J
authors: JJ
authors: Cairó
mesh_terms: D017097:Electric Impedance; D058086:Microalgae; D008854:Microscopy, Electron; D045524:Phycobilisomes; D010798:Phycocyanin; D013010:Sonication; D053545:Spirulina / Q000737:chemistry*
chemical_list: D045524:Phycobilisomes; C002497:allophycocyanin; D010798:Phycocyanin
keywords: Arthrospira sp.; Gas vesicles rupture; Low energy sonication treatment; Microalgae harvesting monitoring; Morphological/structural changes