Biofuel Production from Carbon Dioxide Gas in Polluted Areas

Although carbon dioxide (CO₂) in the air is at a low level (between 0 and 0.03%), the concentration of it is significantly higher in industrial regions. The CO₂ concentration in the atmosphere increases 2–3 ppm every year because of the burning of fossil fuels. Global studies have focused on reducing the carbon dioxide level to the minimum limit (450 ppm) by reducing CO₂ emissions 50–80% by the year 2050. In this study, in order to minimize the CO₂ levels in the Aliağa and Atatürk industrial districts in Izmir, Turkey, S. elongatus from cyanobacteria were isolated from the Gölcük Lake in Ödemiş, Izmir, and were used to produce 1-butanol from CO₂ via photosynthesis as a fuel source, instead of gasoline, for cars. The maximum 1-butanol concentration produced was 79 mg/L, and the 1-butanol_produced/CO_2utilized efficiency was 87.6% in the S. elongatus species isolated from the Gölcük Lake at a temperature of 30 °C, at 60 W light intensity, at pH = 7.1, at 120 mV redox potential, at a flow rate of 0.083 m³/min using CO₂ from the Aliağa industrial region, and at 0.5 mg/L dissolved O₂ concentration. The maximum 1-butanol concentration produced was 59 mg/L, and the 1-butanol_produced/CO_2utilized efficiency was 67.9% in the Atatürk industrial district due to low levels of polluted air in this region. In order to produce 10.000 m³ 1-butanol from 1000 g/L CO₂, the cost was calculated as 0.13 euro, while the addition of plasmid increased the cost to 0.66 euro to produce 10.000 m³ 1-butanol.