Isolation, characterization and localization of extracellular polymeric substances from the cyanobacteriumArthrospira platensisstrain MMG-9

Abstract

Arthrospira platensis is a cyanobacterium known for its nutritional value and secondary metabolites. Extracellular polymeric substances (EPS) are an important trait of most cyanobacteria, including A. platensis. Here, we extracted and analysed different fractions of EPS from a locally isolated strain of A. platensis. Three different fractions of EPS were distinguished. These were EPS released into the medium (REPS), EPS loosely bound to the organism (LEPS) and EPS tightly bound to the organism (TEPS), which were extracted by different procedures. The LEPS fraction was smaller than the other two fractions. The EPS of A. platensis exhibited high diversity. Total protein and carbohydrate content was determined in each of these fractions. The largest amount of total carbohydrates and total proteins was in the TEPS fraction. Eight sugar moieties were detected and analysed in all EPS fractions using HPAE-PAD. Fructose, mannose and ribose were rare sugar residues in all fractions of EPS. With the exception of fructose, all sugars tested for were detected in TEPS. The amount of sugars detected was significantly higher in TEPS compared with the two other fractions, especially for galactose, xylose and glucose. The EPS were localized by confocal laser scanning microscopy (CLSM) after staining with different fluorescent dyes and it was found that A. platensis possessed a thick and smooth layer of EPS around the spiral trichomes.

Trichormus variabilis (Cyanobacteria) Biomass: From the Nutraceutical Products to Novel EPS-Cell/Protein Carrier Systems

“…Released-EPS fraction was obtained according to Ahmed and colleagues procedure [ 81 ]. The culture solutions from the PBRs were centrifuged (5000× g for 20 min) and the supernatants containing REPS were separated from pellets.…”

Influence of culture conditions on the production of extracellular polymeric substances (EPS) by Arthrospira platensis

“…In general, the culture medium of the cyanobacteria is centrifuged or ltrated to remove the cells and then the supernatant or ltrate is concentrated to reduce the water content. Some authors have employed the use of a heat bath (Parikh and Madamwar 2006) or a process using a membrane, such as tangential ultra ltration (Han et al 2014) or micro ltration (Ahmed et al 2014), to attain the concentrate. However, membrane processing depends on the viscosity of the culture medium, pore size distribution and transmembrane pressure (Li et al 2011).…”

Influence of culture conditions on the production of extracellular polymeric substances (EPS) by Arthrospira platensis

“…In general, the culture medium is centrifuged or filtrated to remove cells and then the filtrate is concentrated to reduce the water content. Some authors use a heat bath (Parikh & Madamwar, 2006) or a membrane process, such as tangential ultrafiltration (Han et al, 2014) or microfiltration (Ahmed et al, 2014) to concentrate the medium. However, membrane processing depends on the viscosity of the culture medium, pore size distribution and transmembrane pressure (Li et al, 2011).…”