Ethanol Production from Sunflower Seed Hull Hydrolysate by Pichia stipitis under Uncontrolled pH Conditions in a Bioreactor

Authors: MÜJGAN TELLİ OKUR, NURDAN EKEN SARAÇOĞLU

Abstract: Ethanol production from sunflower seed hull hydrolysate was evaluated using Pichia stipitis NRRL Y-7124 in this study. The hydrolysate was prepared with 0.7 M H_2SO_4 and a solid/liquid ratio of 1/5 (w/v) at 90 °C. Fermentation of detoxified hydrolysate was carried out in a batch bioreactor system under uncontrolled pH operation at initial pH of 6 at 30 °C. The influence of different aeration rates on the fermentability of hydrolysates was investigated. The highest ethanol accumulation, 9.66 g l^{-1}, and a yield of 0.41 g g^{-1} were achieved at the lowest tested flow rate, 2.28 vv^{-1} min^{-1}, from 35 g reducing sugar l^{-1}.

Keywords: Ethanol, Fermentation, Hydrolysate, Pichia stipitis, Sunflower seed hull

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