Bio-fuel production from carbondioxide gas

The carbon dioxide concentration in the atmosphere increases 2-3 ppm every year, due to the combustion of fuels originated from fossils. However, with the climate change and decrease of current energy resources it is necessitated to put the new renewable energies into practice. The feasibility of S. elongatus PCC 7942 cyanobacteria in biofuel production is based on its low cost, making the species isolation easily from the sea, coast and soil and also these bacterias' producing 1- butanol out of CO2 via photosynthesis. These cyanobacteria species which will enable the decrease of carbon dioxide in the atmosphere and render it useful can easily be isolated from the sea or water. In eleven different studies within the scope of this thesis, 1-butanol production from CO2 with S. elongatus PCC 7942 culture has been achieved. In each study, the yields of 1-butanolproduced/CO2utilized have been calculated. The maximum concentration of produced 1- butanol is 35.37 mg/L and 1- butanolproduced/CO2utilized efficiency is 92.4. The maximum outcomes have been achieved under the operation parameters which are 30° C temperature, 60 W intensity of light, pH= 7.1, 120 mV redox potential, 0.083 m3 /sn flow rate with CO2 and 0.5 mg/l dissolved O2 concentration. Among the enzymes on the metabolic trail of the production of 1-butanol via using S. elongatus PCC 7942 cyanobacteria, the concentration of the enzymes 3-hidroxybutyryl-CoA dehydrogenase (Hbd), Trans-2- enoyl-CoA reductase (Ter) and Aldehyde/alcohol dehydrogenase (AdhE2) has been measured with spectrophotometer. At maximum yield; the measured concentrations are 0.016 µg/ml for hbd; 0.0022 µg/ml for Ter and 0.0048 µg/ml for AdhE2. The cost analyses necessary for 1-butanol production has been done and the cost of 1 litre 1-butanol has been determined as maximum 1.31 TL/L. For the eleven studies within the scope of this master thesis, the effects of waiting-period, pH, temperature, addition of NaCl, redox potential, MgSO4, intensity of light, addition of dissolved O2, addition of pAM2991 plasmid to the numbers of S. elongatus PCC 7942 cyanobacteria, productions of 1-butanol, yields of 1-butanolproduced /CO2utilized have been investigated.