COMPARATIVE ANALYSIS OF Spirulina platensis GROWTH BY APPLYING UREA AS A VIABLE NITROGEN SUBSTITUTE FOR Na- NITRATE

Abstract

An experiment was conducted in the 2a Biotech Laboratory of Horticulture Department of Sher-e-Bangla Agricultural University during the period of 1 March 2018 to 15 March 2018 to observe the growth and yield performance of Spirulina platensis. Spirulina platensis was allowed to culture in standard Zarrouks Media (T ) and three different concentrations of Modified Zarrouks Media viz. Zarrouks Media containing 0.01M urea (T 2 ), Zarrouks Media containing 0.02M urea (T 3 1 ) and Zarrouks Media containing 0.04M urea (T ). This experiment was arranged in a Completely Randomized Design. Fifteen days of production was carried out and to find out a promising Spirulina production technology. The growth rate of Spirulina platensis was found to vary in different concentrations of urea solution. The basic concentration of 4mg/L of inoculum gained maximum cell weight (607mg/L) in Zarrouks Medium (ZM) and is significantly (p>0.05) higher than the maximum cell weight (454mg/L) found in Modified Zarrouks Medium (MZM) containing 0.01M of urea solution (T 4 1 ); 0.02M of urea solution (T ) and 0.03M of urea solution (T 3 ) respectively on the 12 th day of the culture period. Similar trend was also observed in the case of chlorophyll a content and optical density (OD) measurement of Spirulina platensis as well. T showed the best result in the given growth parameters such as specific growth rate (0.086), OD (0.66mg/L) and chlorophyll a content (7.133mg/L) in comparison with treatments utilizing the urea solution viz. T 2 . Quality Spirulina production technology can be obtained by using low dosage of urea solution in comparison to other standard type of Spirulina production technology. These findings may be a source of valuable information for a cheap and quality Spirulina production system in Bangladesh by using urea as the readily available nitrogen source.