1فارغ التحصیل کارشناسی ارشد میکروبیولوژی، گروه زیست شناسی ، دانشکده علوم، دانشگاه آزاد اسلامی دامغان
2دانشیار پژوهشکده زیست فناوری، سازمان پژوهشهای علمی و صنعتی ایران، تهران
3استادیار گروه زیست شناسی ، دانشکده علوم، دانشگاه آزاد اسلامی دامغان، ایران
چکیده
چکیده در طی فرآیند پیش تیمار اسیدی باگاس نیشکر محصولات ناخواسته ای مانند فوران‌ها و ترکیبات فنولی تولید می‌شوند که اثر ممانعت کنندگی بر رشد میکروارگانیسم ها دارند. در این تحقیق تأثیر سمیت زدایی با استفاده از آهک اشباع به منظور بررسی اثر فاکتور های pH، دما و مدت زمان واکنش به روش آماری فاکتوریل کامل مورد بررسی قرار گرفت و مقدار اتانول تولید شده توسط مخمر ساکارومایسس سرویزیه در تمام شرایط سمیت زدایی مورد بررسی قرار گرفت. سمیت زدایی به روش آهک اشباع در pH های 10، 11 و 12 در دماهای 40 و 60 درجه سانتی‌گراد به مدت 30 و 60 دقیقه و پس از آن رساندن pH به 5 توسط اسیدسولفوریک انجام شد. سپس سویه موتان ساکارومایسس سرویزیه 5052 PTCC در محیط حاوی هیدرولیزات باگاس سمیت زدایی شده و نشده کشت داده شد. نتایج نشان می‌دهد افزایش pH، دما و مدت زمان سمیت زدایی سبب افزایش حذف فورفورال و در نتیجه افزایش توان تخمیری ساکارومایسس شده است، به طوری که سمیت زدایی در 12pH و دمای 60 درجه سانتی‌گراد به مدت 60 دقیقه، سبب 73% کاهش غلظت فورفورال و از طرفی 81% افزایش بازده تولید اتانول، در مدت زمان 18ساعت، شده است. اما از طرف دیگر کاهش غلظت قند طی سمیت زدایی به روش آهک اشباع در pH و دمای بالا، اصلی‌ترین مشکل در طی این فرایند می‌باشد، به طوری که در 12pH و دمای 60 درجه سانتی‌گراد به مدت 60 دقیقه، به ترتیب 47% و 73% کاهش در غلظت قند کل و گلوکز مشاهده شد.
1Department of biology, Faculty of Science, Islamic Azad University, Damghan, Iran
2Department of Biotechnology, Iranian Research Organization for Science and Technology, Tehran, Iran
3Department of biology, Faculty of Science, Islamic Azad University, Damghan, Iran
چکیده [English]
Abstract During the process of acid pretreatment of sugarcane bagasse, unwanted products such as furans and phenolic compounds are produced which show Inhibitory effect on the growth of microorganisms. In this study, the effect of over-liming detoxification was evaluated by full factorial statistical method where three factors of pH, temperature and reaction time were selected as independent variables. Ethanol production efficiency by Saccharomyces cerevisiae was compared in non-detoxified and detoxified treatments. The Overliming involved increasing the pH of hydrolyzes to 10, 11 and 12, keeping for 30 and 60 min at temperatures of 40 and 60 °c, followed by readjustment of the pH to 5.5. The mutant strain of Saccharomyces cerevisiae PTCC 5052 was cultured in the detoxified and non-detoxified media, containing bagasse hydrolysate. Based on the results increasing the pH, time and temperature resulted in more effective destruction of furfural and lead to better fermentability for hydrolyzes. furfural was decreased 73% after Overliming for 60 minutes, at 60 C, pH 12 and ethanol yield was increased 81% in comparison with non-detoxified hydrolyzed in 18h batch cultivation. But one disadvantage of this method is reducing simultaneous sugars and inhibitor during the reaction, so that, in pH 12 and 60 for 60 minutes, respectively, 47% and 73% of total sugars and glucose was decreased.
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