Browsing by Author "Ozcan Gezen"

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    Lignin recovery from hazelnut shells
    (2023) Ozcan Gezen; Aleyna Filizfidanoğlu; Çağlar Özgener; İrem DENİZ
    The main goal of this work was to study alkaline pretreatment of hazelnut shells (HSs) by utilization of NaOH and Ca(OH)2 with or without glycerol. The highest lignin recovery was obtained for NaOH-glycerol-pretreated HSs. This research also determined the efficiency of enzymatic hydrolysis where xylanase and cellulase were added to the pretreated residue. The highest amount of lignin of 63.2% was achieved when NaOH was used with glycerol in the pretreatment process. These findings revealed that the NaOH-catalyzed glycerol pretreatment applied in this study has great capability to be used in industrial applications.
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    Effect of Different Parameters on Enzymatic Hydrolysis of Hazelnut Shells
    (2024) Ozcan Gezen; irem deniz
    In the last few decades, the increasing levels of environmental pollution have prompted a shift towards alternative energy sources and biobased solutions, such as lignocellulosic biomass. Lignocellulosic biomass (LB) is primarily derived from plants and is composed mainly of polysaccharides, namely cellulose, hemicellulose, and the aromatic polymer lignin. Hazelnut shells (HS), with a high lignin content of 43%, hemicellulose of 30%, and cellulose of 26%, hold promise as a valuable source of LB. In order to process those LB, lignin and hemicellulose are separated using various treatment methods. However, instead of being used solely for combustion, lignin-containing materials can be valorized for a range of purposes, from biomedical applications to the energy sector. In this study, the enzymatic hydrolysis of HS was conducted over different time periods (24, 48, 72, and 96 hours), at different temperature values with varying enzyme concentrations (0.05, 0.1, and 0.25 mL of cellulase/xylanase enzyme cocktail). To enhance the enzymatic hydrolysis, an alkaline pretreatment method using sodium hydroxide (NaOH) was employed. The results demonstrate that the maximum sugar concentration was achieved at 50°C, after 72 hours, and with a cellulase/xylanase cocktail concentration of 0.1 mL.