Culture and production of spirulina (Spirulina platensis) in supernatant of digested rotten potato

Abstract

An experiment was conducted to evaluate culture and growth performance of spirulina
(Spirulina platensis) in supernatant of three different amount of digested rotten potato (DRP), and
Kosaric medium (KM) as control. Three different concentrations such as 25, 50 and 75% of DRP
were digested under aeration and the reddish white coloured supernatant was collected. Spirulina
was inoculated in supernatant of DRP with the addition of 9.0 g/L NaHCO3 and micronutrients,
and KM for a period of 14 days. The cell weight of spirulina was attained a maximum of 11.48
±1.25 mg/L in KM followed by 11.46±1.03, 9.16±0.84 and 8.13±0.73 mg/L in supernatant
of 50, 25 and 75% DRP, respectively on the 10th day of culture. Similar trend was also observed
in the cases of optical density, chlorophyll a, total biomass, specific growth rates and total
biomass of spirulina. Cell weight of spirulina grown in these media had highly significant
(p<0.01) correlation with the chlorophyll a content and total biomass. The growth performance
of spirulina grown in supernatant of 50% DRP was significantly higher than that of spirulina
grown in supernatant of 25 and 75% DRP. The percentage of crude protein (55.15%) of spirulina
grown in supernatant of DRP was little bit lower than that of spirulina cultured in KM (58.70%).
The crude lipids (17.15%) of spirulina cultured in supernatant of 50% DRP was almost two and
half times higher than that of spirulina grown in KM (6.33%). It indicates that for the production
of spirulina with high lipid content, supernatant of DRP may be used. Therefore, mass culture of
S. platensis may be done in supernatant of 50% DRP.