Effect of light spectrum, salinity, and glucose levels on Spirulina morphology

Abstract

This study evaluated how light spectrum, salinity, and glucose level affect Spirulina morphology, using response surface methodology (RSM). A full factorial experiment was conducted including three light conditions with different predominant spectral characteristics (“white”: 100% white; “red”: 80% red, 15% blue, and 5% green; and “yellow”: 80% yellow, 15% blue, and 5% green), four NaCl concentrations (0, 5, 15, 30 g/L), and four glucose levels (0, 1.5, 2, 2.5 g/L). Light spectrum conditions and salinity had significant effects on the filament length, spiral diameter, and screw pitch length. Glucose only had a significant effect in terms of the spiral diameter. The maximum filament length (1274 μm; under 30 g/L NaCl and 2.5 g/L glucose), spiral diameter (47 μm; under 1 g/L NaCl and 2 g/L glucose), and screw pitch length (112 μm; under 1 g/L NaCl and 2 g/L glucose) were attained under yellow light. In line with the simulation, more compacted filaments, that is, with a greater diameter (41 μm) and shorter screw pitches (78 μm), are observed under “red” light (4 g/L NaCl and 2.5 g/L glucose). Because longer but compact filaments are desirable for easier harvesting, we recommend a light spectrum that is predominantly red with a NaCl concentration of 5.8 g/L deprived of glucose, for the cost‐effective harvesting of Spirulina biomass.

Development of Low-Cost Growing Media with Mungbean as A Source of Carbon for Spirulina

“…It is a type of unicellular blue-green microalgae that can be grown in large quantities with a high level of carbonate and bicarbonate in tropical and subtropical water bodies (Shen et al, 2021). The filaments are up to 500 mm long and have a diameter of 3-5 mm (Nosratimovafagh et al, 2023). In commercial cultivations, Spirulina can successfully be grown on freshwater, saltwater, and brackish water.…”