Growth Characteristics of Mixotrophic Scenedesmus acuminatus under Semi-Continuous Culture System

Abstract

The purpose of this study was to determine optimum value of aeration, acetate dosage, and CO2 input for the cultivation of Scenedesmus acuminatus;. Highest specific growth rate and maximum biomass productivity was obtained by the aeration of 0.72 vvm and lower specific growth rates and maximum biomass productivity were obtained for other aeration tests. When putting 0.3 M of ammonium acetate in JM medium, the highest specific growth rate and maximum biomass productivity were obtained. CO2 input tests were performed during semi-continuous culturing tests. The highest specific growth rate (0.460 d-1) and maximum biomass productivity (0.936 g L-1 d-1) were obtained after replacing 50% of solution with 0.3 M of acetate solution for CO2 input tests. However, more dilutions after the first dilution resulted in lower specific growth rate and maximum biomass productivity. In aeration tests, the highest specific growth rate (0.381 d-1) and maximum biomass productivity (0.253 g L-1 d-1) were obtained when cultivating it with JM medium, but the specific growth rate and maximum biomass producitivty were significantly decreased when 50% of solution was replaced by acetate containing solution. Key words: Scenedesmus acuminatus, Semi-Continuous Cultivation, Carbon Dioxide, Nitrogen, Phosphate, Acetate