Question

Is Spirulina a Bacteria or Algae?

Answer 1

Hint: Cyanobacteria are aquatic and photosynthetic i.e they live in the water and can manufacture their own food. They are unicellular. They are also known as blue green algae.

Complete answer:
Spirulina is a genus of blue green algae belonging to the family of Oscillatoriaceae. They are gram negative with a soft cell wall that consists of complex sugars and proteins. They are filamentous and undifferentiated. Phycocyanin is the main pigment that is blue in color. They inhabit freshwater, alkaline lakes, etc and some are marine also. They are also found in hot springs. They have high nutritional value and are edible.
Reproduction occurs through fragmentation, akinetes, hormogons and sometimes by heterocyst.

Like most cyanobacteria, Spirulina is an obligate photoautotroph and cannot be grown in the dark media containing organic sources of carbon. The phycocyanin, biliproteins involved in the light-harvesting reactions, have been resolved by gel electrophoresis in S. platensis and S. maxima and isolated from the former.

The life cycle of Spirulina for laboratory culture purposes is rather simple. A mature trichome is broken into several pieces through the formation of specialized cells, necridia, that undergo lysis, giving rise to biconcave separation disks. The fragmentation of the trichome at the necridia produces gliding, short (two to four cells) chains of cells, and the hormogonia, which move away from the parental filament to give rise to a new trichome. The cells in the hormogonium lose the attached portions of the necridial cells, becoming rounded at the distal ends with little or no thickening of the walls. During this process, the cytoplasm appears less granulated.

Note:
Spirulina is a biomass of cyanobacteria that can be consumed by humans and animals. The three species are Arthrospira platensis, A. fusiformis, and A. maxima. Cultivated worldwide, Arthrospira is used as a dietary supplement or whole food.