Abstract    In this study, the hydrolysis of pretreated sorghum stem and rice husk was investigated at various initial enzyme concentrations and substrate loadings. The slowdown in enzymatic hydrolysis of lignocellulosic materials with conversion has often been attributed to decreasing the activity of enzyme. A kinetic model was developed and expressed mathematically based on enzyme deactivation for enzymatic hydrolysis of lignocellulosic materials. The decline in activation of the adsorbed enzyme is represented by a second order reaction. The models were used to fit experimental data of sorghum stem and rice husk hydrolysis. The models basic parameters which can explain the effects observed experimentally were determined and discussed. The model performed well in predicting hydrolysis trends at experimental condition.

Keywords    Enzymatic hydrolysis, Kinetic modeling, Enzyme deactivation, Rice husk, Sorghum bicolor

چکیده    در کار حاضر، هیدرولیز ساقه سورگوم جارویی و شلتوک برنج پیش‌تیماری شده تحت مقادیر متفاوت از غلظت‌های اولیه آنزیم و میزان بارگذاری سوبسترا مورد بررسی قرار گرفت. کاهش سرعت هیدرولیز آنزیمی مواد لیگنوسلولزی، اغلب به‌ کاهش فعالیت آنزیم نسبت داده شده است. از اینرو یک مدل سینتیکی ریاضی برای هیدرولیز آنزیمی مواد لیگنوسلولزی بر مبنای غیرفعال شدن آنزیم ارائه گردید. در این مدل، کاهش فعالیت آنزیم جذب شده توسط یک واکنش درجه دوم توصیف شد. مدل ارائه شده با داده‌های آزمایشگاهی حاصل از هیدرولیز ساقه سورگوم و شلتوک برنج برازش داده شد. پارامترهای سینتیکی مدل با تطابق نتایج آزمایشگاهی تعیین و مورد ارزیابی قرار گرفتند. عملکرد مدل در تخمین روند هیدولیز آنزیمی تحت شرایط مختلف بسیار خوب ارزیابی گردید.

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