The utilization of hazelnut shell for ethanol production

The purpose of this study is to investigate utilization of an important agricultural waste in Turkey such as hazelnut s helis for ethanol productîon. This study consist of three parts. At the first part, the kinetic model of hazelnut shells hydrolysis with sulfuric acid was studied. Reactions were carried out between 0,1-0,7 M sulfuric acid concentration with 1/7,14 solid to liquid ratio at temperature of 100-120 °C. At the second stage of this \vork, the effect of different pretreatment methods upon to the fermentation of hazelnut shell hydrolysate by Pichia stipitis were investigated in shaking flasks experiments. Among ali tested detoxifîcation methods, the most effectîve pretreatment regarding to ethanol concentration reached was, the one in which hazelnut shells were first treated with % 3 NaOH at room temperature, followed by overliming and then treated with charcoal twice at 60 °C, one hour. With this method, a ma x i mal ethanol concentration of 16,79 g/l was reached. This value is equal to %91,25 of ethanol concentration that was obtained from synthretic D-xyIose under sanı e conditions. in the third part of this work, D-xylose and hazelnut shell hydrolysate fermentations were carried out in a pH controlled fermentor system. Fermentatıon experiments for fermentatîon of D-xylose by Pichia stipitis were carried out by using di t teren t air f!ow rates and initial substrate concentration chosen by using Box-WiIson experimental design. Optimum fermentation conditions were estimated by using Design Expert computer package program. 7,39 g/1 ethanoi was obtained from the optimum air flow rate and substrate concentration vvith hazelnut shell hydrolysate fermentation. 1 his value is equal to % 82 of ethanoi concentration that was obtained from synthetic medium at the same conditions. in addition, in the pH controlled fermentor system, kinetic models \vcrc developed for biomass growth, substrate consuptions and ethanoi produetion for D-xylose fermentation. Key Words : Ethanoi fermentation, detoxification methods, hazelnut shells, Pichia stipitis