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    Öğe
    Biochemical properties of ?-glucosidase from Turkish Hacihaliloglu apricot (Prunus armenica L.) as affected by harvest year
    (Elsevier Science Bv, 2017) Unal, Mustafa Umit; Sener, Aysun
    beta-glucosidase was extracted and purified from Turkish Hacihaliloglu apricot variety and some of its biochemical properties were studied in a two-year study (2008 and 2009). Two isoenzymes (isoenzyme A and B) were obtained upon ammonium sulfate fractionation, ion exchange chromatography using DEAE-Toyopearl 650 M and gel filtration chromatography using Sephadex G-100. The pH optimum was found to be 5.0 for both isoenzymes. The optimum temperature for isoenzyme A activity in both years was found to be 50 degrees C, whereas those for the isoenzyme B in 2008 and 2009 were 50 degrees C and 55 degrees C, respectively. Km values of the isoenzyme A and B were found to be 2.49 and 1.12 mM in 2008, and 2.41 and 1.06 mM in 2009, respectively. The Z values for isoenzyme A in 2008 and 2009 were found to be 20.3 degrees C and 17.9 degrees C, respectively. Those for isoenzyme B in 2008 and 2009 were 21.1 degrees C and 23.0 degrees C, respectively. Ea values for isoenzyme A were 108.1 kjimolK and 1223 kj/molK, while those for isoenzyme B were found to be 103.5 kj/mol K and 95.1 kjimolK in 2008 and 2009, respectively. Of the inhibitors tested, CaCl2 was the most effective. (C) 2017 Elsevier Ltd. All rights reserved.
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    Öğe
    Effect of temperature and nitrogen supplementation on bioethanol production from waste bread, watermelon and muskmelon by Saccharomyces cerevisiae
    (Taylor & Francis Ltd, 2022) Unal, M. Umit; Chowdhury, Golam; Sener, Aysun
    This study was undertaken to investigate the effect of temperature (25 degrees C and 30 degrees C) and nitrogen supplementation (with 20 g/L peptone or without) on bioethanol production from waste bread, watermelon and muskmelon feedstocks by Saccharomyces cerevisiae. Nitrogen addition resulted in higher ethanol yields at both temperatures. Fermentation at 30 degrees C produced a higher ethanol yield than at 25 degrees C. The highest ethanol yield of 0.502 gethanol /g fermentable sugar, at 98.22% of the theoretical maximum, was obtained from the fermentation of muskmelon juice at 30 degrees C with nitrogen supplementation. Ethanol yields at both temperatures were significantly different (p < 0.05) between the trials with nitrogen and without nitrogen supplementation for watermelon and muskmelon but not for waste bread hydrolysate. On the other hand, ethanol yields showed significant differences (p < 0.05) at 25 degrees C and 30 degrees C for all feedstocks with nitrogen and without supplementation.