The effects of nitrogen deficiency on the production of polyhydroxybutyrate (PHB) using Spirulina platensis

Abstract

The effects of nitrogen deficiency at the level of 0% (N-), 50% (N-), and 100% (N-) for the growth of Spirulina platensis (Cyanophyceae) for the production of Polyhydroxybutyrate (PHB) was investigated. Biomass and optic density of the cell under laboratory conditions were measured. Spirulina platensis cultures were grown in Zarrouk medium and kept at the constant room temperature of 25±2°C, illuminated with fluorescent lamps at Photosynthetic Active Radiation (PAR) level of 120 μmol m2 s -1 with photoperiod of 24:0 (light:darkness, L:D) and aerated continuously. The experiment was carried out with three replications. The percentages of PHB measured were 1.13, 1.43, 2.61 and biomasses obtained were 2.30, 2.92, and 1.85 g/L for control (0%N-), 50% N(-) and 100% N(-), respectively for S. platensis biomass harvested. The highest PHB value and the lowest biomass were recorded from the culture treated at the level of 100% N(-).