Abstract:
This work involved the study of ethyl alcohol production from the hydrolysis of corn stalk with sulfuric acid solution. The corn stalks of Suwan 1 which were already harvested ( 3 months old) were used as raw material in this experiment. The work can be devided into three stages, pre-hydrolysis, hydrolysis and fermentation as the following. Pre-hydrolysis stage, the particle sizes of corn stalk were studied to find their effect on the yield of total reducing sugar. It was found that the total reducing sugar acquired from particle size of 10 mesh was more then that of 4 and 5 mesh by the yield of 10.6% and 24.5% respectively. Each run in this stage was performed at temperature of 100oc, about 50 minutes, with sulfuric acid solution of 4.4% (wt. / vol.) and the ratio of volume of sulfuric acid solution (ml) :weight of corn stalk (gm) was 10:1. The concentration of reducing sugar in the solution was about 1.5%. When the pre-hydrolysis solution was reused to extract dried corn stalk, the concentration of reducing sugar increased to 2.8%, which is about 90.6% more. Hydrolysis stage, the corn stalk from the pre-hydrolysis stage was steeped in 80% sulfuric acid for 3 hours. After that, it was diluted to 8% concentration and the ratio of volume of the sulfuric acid solution (ml) : weight of corn stalk (gm) was 8:1. Then, the hydrolysis was taken place in an oil bath at the temperature of 100oc for 20 minutes, the concentration of the reducing sugar was 1.4%. Another experiment was performed at 121oc, the corn stalk from the pre-hydrolysis was steeped in 80% sulfuric acid solutions for 2 hours. After that it was diluted to 8% concentration, the ratio of volume of the sulfuric acid (ml):weight of corn stalk (gm) was 6:1. And then, the solution was hydrolyzed with steam in an autoclave at the temperature of 121oc for 7 minutes. The concentration of the acquired product was 2.1% Fermentation stages, the growth rate of Saccharomyces cerevisiae var. ellipsoideus in the sugar solution form corn stalk was studied. The starter in a shaking flask at the speed of 240 rpm. Cultivation yeast in medium containing of NH4Cl 0.13% NgSo4.6H2O 0.01% yeast extract of 0.85% (wt./vol.) was added and then adjust pH to 4.5. it was founded that the best condition for the growing yeast was taken place in the solution of concentration of 4o brix, following 8o and 12o brix respectively. The maximum growth rate of the yeast was between 12-24 hours. In the fermentation stage, the solution was adjusted the absorbance to 0.1 at 580 nanometer. The solution was shaking for 12 hours, it was found that alcohol concentration reached 2.5% at the 60th hour in 8o brix solution.