Biobutanol production from Scenedesmus in wastewater

In this thesis study, the biobutanol production potential of Scenedesmus sp. grown in TAP and synthetic wastewater was investigated. For this purpose, microalgae were studied under various concentrations of urea and different light intensities. The optical densities (OY), biomass concentrations, carbohydrate amounts, carbohydrate percentage, carbohydrate yield and biobutanol concentration of Scenedesmus sp. were investigated. The results showed that the highest optical density value was 0.83 at 80 mg/L urea, and the lowest value was 0.12 at 20 mg/L. The highest value of optical density was found to be 0.83 at 80 μmol/m-2s-1 of light intensity, while the lowest value was measured as 0.11 at 20 μmol/m-2s-1. The biomass concentrations of microalgae under various urea and light intensities were investigated. The maximum biomass concentration for urea was 0.85 g/L at 80 mg/L, while the highest biomass concentration for light intensity was 0.85 g/L at 80 μmol/m-2s-1. Moreover, we examined the carbohydrate amounts of microalgae under different urea and light intensities. The highest carbohydrate value was measured as 0.24 at 80 mg/L of urea. Similarly, the highest carbohydrate value was measured as 0.24 g/L at 80 μmol/m-2s-1. In addition, the carbohydrate percentages of microalgae at various urea concentrations and light intensities were investigated. The maximum carbohydrate percentage was achieved at 60 mg/L of urea, with a yield value of 30%. In the measurement made in light intensity, the highest carbohydrate value was measured at 80-100 μmol/m-2s-1, and a 28% carbohydrate yield was measured. At the 80 mg/L of urea, and light intensity, biobutanol concentration was 0.04. In conclusion, Scenedesmus sp. can effectively be used for biofuel production in laboratory settings, but, a situation that may necessitate its application in larger-scale industries.