Investigated of sunflower seed hulls hemicellulose hydrolysate fermentation conditions and kinetic to the alcohol

Ill INVESTIGATED OF SUNFLOWER SEED HULLS HEMICELLULOSE HYDROLYSATE FERMENTATION CONDITIONS AND KINETİCS TO THE ALCOHOL ( M. Sc. Thesis ) Müjgan TELLİ OKUR GAZI UNIVERSITY INSTITUTE OF SCIENCE AND TECHNOLOGY December 2003 ABSTRACT In this study, the potential use of hemicellulosic hydrolysate derived from sunflower seed hulls in the ethyl alcohol production with Pichia i stipitis yeast was investigated. For this purpose, the seed hulls pressed baggase obtained from Antakya region was hydrolyzed with sulfuric acid (0.7 M) at 90°C having 1/5 solid/liquid (g/mL). In the first part of the study, the influence of various pretreatments of hydrolysate to reduce toxicity on the fermentability of hydrolysate was investigated. Beside these, Pichia stipitis yeast was adapted to hydrolysate and the effect of adaptation was studied. Fermentation experiments performed in shaking flasks at 30°C indicated that overliming with CaO+Na2S03 addition as pretreatment prior to fermentation improved the fermentation performance of hydrolysate better than the other methods. In the second part of the study, the effects of initial pH and shaking rate were studied in shaking bath experiments at 30°C. The highest alcohol level 11 g/L was achieved at initial pH of 6 and 100 rpm shaking rate from a hydrolysate containing 48 g/L reducing sugar. The alcohol yield and alcohol production rate were 0.32 g/g and 0.065 g/L hour, respectively. In the last part of the study, the fermentation of sunflower seed hulls hydrolysate was carried out in a small scale fermentor set-upIV at 30°C without any pH control. The influence of air flow rate was investigated. To represent the fermentation kinetics, Monod type equations were tested. Science Code : 603.02.01 Key Words :Sunflower seed hulls hydrolysate, Ethyle Alcohol, Fermentation, Pichia stipitis. Page Number :181 Thesis Supervisor : Prof. Dr. Nurdan SARAÇO?LU