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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Iranian Journal of Basic Medical Sciences
- نوع مقاله: Journal Article
- کلمات کلیدی: optimization,Xylanase,Random Mutagenesis,Bacillus mojavensis,H/C ratio
- چکیده:
- چکیده انگلیسی: Objective(s):[p1] This study highlights xylanase overproduction from Bacillus mojavensis via UV mutagenesis and optimization of the production process.
Materials and Methods:Bacillus mojavenis PTCC 1723 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 [AGA2] wastes was designed with Minitab software for the best overproducer mutant.
Results: H/C ratio of 3.1 was measured in mutant number 17 in comparison with the H/C ratio of the parental strain equal to 1.6. Selected mutant produced 330.56 IU/ml xylanase. It was 3.45 times more enzyme than the wild strain with 95.73 IU/ml xylanase. Optimization resulted 575 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 7, after 48 hr incubation at 37°C, and the shaking rate of 230 rpm. Optimum xylanase activity was assayed at pH 7 and 40°C. Enzyme stability pattern shows it retains 62% of its initial activity at pH 9 after 3 hr. It also maintains up to 66% and 59% of its initial activity after 1 hr of pre-incubation at 70°C and 80°C.
Conclusion: Mutation and optimization caused 5.9 times more enzyme yield by mutant strain. Also this enzyme can be categorized as an alkali-tolerant and thermo-stable xylanase.- انتشار مقاله: 19-09-1393
- نویسندگان: Shokoofeh Ghazi,Abbas Akhavan Sepahy,Mehrdad Azin,Khosro Khaje,Ramazanali Khavarinejad
- مشاهده
- جایگاه : پژوهشی
- مجله: Advanced Research in Microbial Metabolites & Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Response surface methodology,culture optimization,biomass production,Picochlorum sp. RCC486,one-way ANOVA
- چکیده:
- چکیده انگلیسی: Abstract
Microalgae biomass production and optimization is necessary to overcome food security problems and address environmental topic as well as high-value compounds production. In this investigation the influence of three culture media (BBM, BG-11 and Guillard f/2) on the growth and biomass production of the Picochlorum sp. RCC486 microalgae was evaluated.
One- way ANOVA with Tukey’s HSD and Fisher’s LSD tests were used to test the effect of different culture media on optical density. Then the maximum optical density and biomass production by Picochlorum sp. RCC486 was evaluated using response surface methodology. A historical data of response surface methodology was used to find the optimum response, which yields the highest biomass production.
Microalgal growth in Guillard f/2 medium reached highest cell count in the considered time period and the microalgae presented highest biomass production in comparison with other two culture media (BBM and BG-11). Additionally, biomass productivity(58 mg L-1d-1 ), specific growth rate (0.681d-1), dry weight (1.516 g L-1) and cell density(52.9 ×106 cells mL-1) were highest in comparison with other two culture media. The predicted optical density and biomass production using historical data design were close to their experimental values corresponding to 1.50313 and 1.976gL-1 respectively. while the concentrations of nitrogen source and phosphorus source were achieved in concentrations of 1345.55 mg L−1, 6.983 mg L−1 respectively. Under the optimum condition, the biomass yield was1.961 gL-1 which is 0.76% less than the predicted value. Also the study reported that the biomass production of Picochlorum sp. RCC486 improved from 1.516 g L-1 in defined Guillard f/2 medium to 1.961 g L-1 in modified Guillard f/2 medium resulting 22.69% increase. Thus, Picochlorum sp. RCC486 biomass content could be enhanced by optimizing nitrogen and phosphorus concentrations.- انتشار مقاله: 10-05-1397
- نویسندگان: Mohammad Haji Abolhasani,Maliheh Safavi,Mohammad Taghi Goodarzi,Seyed Mehrdad Kassaee,Mehrdad Azin
- مشاهده