Growth Kinetics of Algae Cells Under Heterotrophic Conditions

Abstract

Algae cells were cultivated both at micro and macro level under heterotrophic conditions in a prepared growth medium to analyze the cell response under the given conditions. Micro-cultivation of the cells was carried out separately in small-sized flasks, whereas mass cultivation of the cells was performed in a large-size tank. Pre-culturing of green algae Chlorella vulgaris (C Vulgaris) proved that the cells responded productively in the organic mode of growth medium. Saturated cycles of DO concentration in the range of 14 mg/L/d or above were observed during mass cultivation of C Vulgaris along with consequent occurrence of lowered pH values, which vindicated the optimum algae growth. The optimum C Vulgaris growth transpired that during the log phase every 1 g growth in C Vulgaris cell mass caused a COD reduction of 13%. Similarly, every 1g drop in C Vulgaris growth during stationary or death phase coincided with a COD increase of 730 mg l-1 likely caused by the release of soluble organic fraction of the decaying algae cells along with the generation of insoluble algae detritus in the cultivation medium.