The influence of materials added to fermentation medium on ethanol production

The production of ethanol with the method of fermentation has gained great impetus due to advancement in technology, the rapid increase in the world population, the run out of petroleum fuels reserves in crust of earth, the repercussions of the skyrocketing of costs in national economy and protection and use of the national resources. That is why, the determination of conditions that will increase the output efficiency of ethanol is necessary for reproduction and development of microorganisms and the efforts being made on this subject have great importance. The purpose of this study is to investigate the effects of materials added to fermentation medium that is created by Saccharomyces cerevisiae, on ethanol production, ethanol concentration, production rate and pH. The study is executed in three steps. In the first step NaY, MNT and KLN are added to medium with an initial pH value of 4,5. Under these circumstances, adding 15 gL-1 NaY to fermentation medium containing 200 gL-1 sugar, production rate increased. When the medium contains 10 gL-1 MNT, the ethanol concentration reached to maximum value in the existence of 200 gL-1 sugar, on the otherhand the time required to reach to maximum concentration is decreased. The ethanol production rate is increased by 16 percent. The presence of 5 gL-1 KLN did not have any influence on ethanol concentration, but the production rate is raised resulting in approximately %50. In the second stage, active carbon, bentonite and talk are inserted into vii fermentation medium. The experiments were made with a fermentation medium which contains 100 gL-1 sugar. Presence of 10 gL-1 bentonite, yield increased %6, when 10 gL-1 active carbon exists time that was required for reaching to maximum yield decreased. The supplementation of talk adversely affected the fermentation. In the third stage, we investigated the effect of change of Na, Ca and Mg ions on ethanol yield. The maximum ethanol concentration level was reached at the lowest Na concentration, the middle Ca concentration and the middle Mg concentration for the coded values of 931mgL-1, 1515 mgL-1, 128 mgL-1 respectively.