An experiment was conducted to evaluate the Specific Growth Rate (SGR) and affiliated physico-chemical attributes of Spirulina platensis in supernatant of three different concentrations of digested rotten guava (DRG), and Kosaric Medium (KM) as control. Three different concentrations such as 20, 40 and 60 rotten guavas were allowed to digest under aerated condition. After 34 days, the reddish white colored supernatant was screened and taken in 2.0 L conical flask with three replications. Then, Spirulina was inoculated to grow in these three digested rotten guava media (DRGM) (treatments) with the addition of 9.0 g/L NaHCO3, micronutrients and KM for a period of 14 days. The cell weight of Spirulina was attained a maximum of 12.43±0.20 mg/L (dry wt. basis) in KM followed by 0.818 ± 0.003, 0.815 ± 0.0015 and 0.809± 0.0012 mg/L in supernatant of 60, 20 and 40% DRGM, respectively. The percentage of crude protein (53.35 ± 0.32%) of Spirulina grown in supernatant of 40% DRGM significantly (p < 0.05) lower than that of cultured in KM (58.36 ± 0.32%). But crude lipids (10.15 ± 0.14%) of Spirulina cultured in supernatant of 60% DRGM was significantly (P < 0.05) and almost two times higher than that of Spirulina grown in KM (6.30 ± 0.22%). It means that for the production of high lipid content in Spirulina, supernatant of DRGM may be used. The physico-chemical parameters viz. light intensity (2748 to 2768 lux/m2/s), temperature (19.0 to 22.2°C), pH (8.1 to 10.6), alkalinity (1522 to 2698 mg/L), nitrate-N (1.25 to 3.64 mg/L) and phosphate-P (11.30 to 55.40 mg/L) were within the optimum level during the culture period. So, mass culture of Spirulina may be practiced in supernatant of 60% DRGM.
Md Saiful Islam, Md Ahsan Bin Habib, Md Hashibur Rahman, Md Arifuzzaman, Sagorika Smriti, Al-Amin, Sharmin Sultana Mukti. Assessment of the physico-chemical properties and specific growth rate (SGR) of Spirulina platensis in lab scale cultivation. International Journal of Fisheries and Aquatic Research, Volume 7, Issue 2, 2022, Pages 21-29