UV mutagenesis for the overproduction of xylanase from Bacillus mojavensis PTCC ۱۷۲۳ and optimization of the production condition
- سال انتشار: 1393
- محل انتشار: مجله علوم پایه پزشکی ایران، دوره: 17، شماره: 11
- کد COI اختصاصی: JR_IJBMS-17-11_004
- زبان مقاله: انگلیسی
- تعداد مشاهده: 386
نویسندگان
Department of Microbiology, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran
Department of Microbiology, College of Basic Science, Islamic Azad University, Tehran North Branch, Tehran, Iran
Department of Biotechnology, Iranian Research Organization for Science and Technology, Tehran, Iran
Department of Biotechnology, College of Basic Science, Tarbiyat Modares University, Tehran, Iran
Department of Microbiology, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran
چکیده
Objective(s):[p۱] This study highlights xylanase overproduction from Bacillus mojavensis via UV mutagenesis and optimization of the production process. Materials and Methods:Bacillus mojavenis PTCC ۱۷۲۳ underwent UV radiation. Mutants’ primary screening was based on the enhanced Hollow Zone Diameter/ Colony Diameter Ration (H/C ratios) of the colonies in comparison with the wild strain on Xylan agar medium. Secondly, enzyme production of mutants was compared with parental strain. Optimization process using lignocellulolytic [AGA۲] wastes was designed with Minitab software for the best overproducer mutant. Results: H/C ratio of ۳.۱ was measured in mutant number ۱۷ in comparison with the H/C ratio of the parental strain equal to ۱.۶. Selected mutant produced ۳۳۰.۵۶ IU/ml xylanase. It was ۳.۴۵ times more enzyme than the wild strain with ۹۵.۷۳ IU/ml xylanase. Optimization resulted ۵۷۵ IU/ml xylanase, with wheat bran as the best carbon source, corn steep liquor as the best nitrogen source accompanied with natural bakery yeast powder, in a medium with pH ۷, after ۴۸ hr incubation at ۳۷°C, and the shaking rate of ۲۳۰ rpm. Optimum xylanase activity was assayed at pH ۷ and ۴۰°C. Enzyme stability pattern shows it retains ۶۲% of its initial activity at pH ۹ after ۳ hr. It also maintains up to ۶۶% and ۵۹% of its initial activity after ۱ hr of pre-incubation at ۷۰°C and ۸۰°C. Conclusion: Mutation and optimization caused ۵.۹ times more enzyme yield by mutant strain. Also this enzyme can be categorized as an alkali-tolerant and thermo-stable xylanase.کلیدواژه ها
Bacillus mojavensis, H/C ratio, optimization, Random mutagenesis, Xylanaseاطلاعات بیشتر در مورد COI
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