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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Journal of Particle Science & Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Staphylococcus aureus,Nanoparticles,Antibacterial agents,Fresh minced meat,LDPE films
- چکیده:
- چکیده انگلیسی: Antibacterial properties of TiO2, ZnO as well as mixed TiO2-ZnO nanoparticles coated low density polyethylene films on Staphylococcus aureus PTCC1112 were investigated. Bactericidal efficiency of 0.5, 1 and 2 Wt% for TiO2 and ZnO nanoparticles and also 1 Wt% mixed TiO2-ZnO nanoparticles with TiO2:ZnO ratios of 25:75, 50:50 and 75:25 were tested under UV and fluorescent lights exposure at two different states: films alone (Direct effect) and fresh calf minced meat packed inside the films. ZnO nanoparticle showed good antibacterial properties against Staphylococcus aureus PTCC1112. Maximum CFU reduction of 99.59% and 97.07% were obtained using 2 and 1 Wt% ZnO nanoparticle coated LDPE film under UV light for films alone as well as 62.43% and 59.57% for fresh calf minced meat packed. The best antibacterial functionalities of 96.25% and 77.11% CFU reduction were recorded for 1 Wt% TiO2 nanoparticle coated LDPE films in the presence of UV light at direct contact with bacteria and fresh calf minced meat packed, respectively. In the case of mixed TiO2-ZnO, maximum CFU reductions of 98.37% and 97.84% were obtained using 50:50 ratio of TiO2: ZnO nanoparticles at the presence of UV light for direct effect and fresh calf minced meat packed, respectively. 2 Wt% ZnO nanoparticle as well as 1 Wt% mixed TiO2-ZnO nanoparticles in ratio of 50:50 coated LDPE films were identified as the best case to improve shelf life and prevent Staphylococcus aureus PTCC1112 growth in fresh calf minced meat.
- انتشار مقاله: 26-07-1395
- نویسندگان: Arin Marcous,Susan Rasouli,Fatemeh Ardestani
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Engineering, Transactions A: Basics
- نوع مقاله: Journal Article
- کلمات کلیدی: Lactobacillus,Lactic Acid,Batch submerged culture,Monod kinetic model
- چکیده:
- چکیده انگلیسی: Cell growth and lactose consumption profile of five Lactobacillus Strains: bulgaricus, casei, lactis, delbrueckii and fermentum has been investigated. Experiments of cell growth and substrate utilization were conducted in batch submerged culture of whey with added lactose and some other growth factors. Fitness assessment of experimental data on the cell growth and lactose consumption by Monod kinetic model was performed using the curve-fitting tool in Mat Lab software. Lactobacillus casei subsp. casei PTCC1608 with R2, μmax and Ks as 0.965, 0.435 h-1 and 27.05 g L-1, respectively showed the most fitness with Monod equation. Between the investigated strains, Lactobacillus fermentum PTCC1744 also showed an acceptable consistency with Monod kinetic model (R2= 0.951). Its μmax and Ks values were 0.134 h-1 and 54.46 g L-1, respectively. Lactobacillus delbrueckii subsp. Bulgaricus PTCC1737 (R2= 0.891) and Lactobacillus delbrueckii subsp. lactis PTCC 1743 (R2=0.857) did not have an accepted fitness with Monod kinetic model.
- انتشار مقاله: 11-10-1348
- نویسندگان: Ghasem Najafpour,Fazllolah Rezvani,Fatemeh Ardestani
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Biodegradation,Biochemical test,Contaminated soils,Oil removal bacteria
- چکیده:
- چکیده انگلیسی: Microbialbiodegradation is known as an effective and harmless method to overcome environmental pollution with oil hydrocarbon. Some bacterial species were isolated from the Sarvestan oilfields (Iran, Fars province), then identified and applied for oil hydrocarbon decomposition. A carbon-free minimum medium (CFMM) containing 1% crude oil was used to isolate bacteria through incubation at 30°C in the dark at 200 rpm for 7 days. Different methods were used to identify the hydrocarbon oil decomposing bacteria: gram staining, squalene hydrolysis, catalase, production of arginine dihydrolase, gelatin liquefaction, hydrogen sulfide production, levan production, methyl red, oxidase, nitrite reduction, oxidative/fermentative, starch hydrolysis and Tween-80 hydrolysis tests. Nine different oil decomposing bacterial species were isolated. All the species grew well at 28 and 35°C, while four isolates containing of Bacillus sp. SA13, Pantoea sp. SA1112, Pseudomonas aeruginosa sp. SA21, and Bacillus sp. SA23 were capable of growing in a temperature of up to around 42°C. The minimum salt tolerance for isolates, except for Enterobacter sp. SA711, was 8%; Bacillus sp. SA212 had the highest tolerance of 15% sodium chloride. Acinetobacter sp. SA172, Enterobacter sp. SA711, Pseudomonas sp. SA75, Bacillus sp. SA212 and Bacillus sp. SA23 had the most growth rate in the CFMM. The highest percentages of oil removal obtained were 89% for Enterobacter sp. SA711, 86% for Acinetobacter sp. SA172, and 68% for Pseudomonas sp. SA75. The three isolated bacterial strains from the contaminated soil of the Sarvestan area had a good ability to degrade oil hydrocarbon. Therefore, they could be used commercially for the bioremediation of this region.
- انتشار مقاله: 30-06-1397
- نویسندگان: Mohsen Kojuri,Fatemeh Ardestani
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Aspergillus flavus,Bioremediation,Lignocellulosic wastes,Microbial protein,Solid-state fermentation
- چکیده:
- چکیده انگلیسی: The lignocellulosic wastes produced in food industries are suitable raw materials for the production of biological products. In this study, the solid state fermentation of Aspergillus flavus on lignocellulosic wastes was evaluated for microbial protein production. The fraction of the full factorial method was applied for experiment design and process optimization. The results analysis was performed through signal to noise statistical index using the Taguchi approach via Qualitek-4 software. Glycine, ammonium sulfate and iron sulfate concentration as well as temperature were considered as effective parameters. The maximum biomass concentration of 45.7 g/kg containing 55.75% (w/w) pure protein was obtained at optimal conditions including 0.5, 0.02, and 2 g/kg of ammonium sulfate, iron sulfate and glycine, respectively, at 25 °C. Ammonium sulfate (33.78% (w/w) contribution) and culture temperature (31.98% contribution) were evaluated as the most effective factors on biomass and microbial protein production. The highest interaction occurred between ammonium sulfate and glycine with an interaction severity index of 50.03%. The low deviation of 3.94% was determined between optimum theoretical biomass concentration (43.9 g/kg) and the experimentally measured one (45.7 g/kg). Due to the high protein content of 55.75% (w/w), Aspergillus flavus was introduced as a suitable strain for industrial protein production.
- انتشار مقاله: 28-09-1395
- نویسندگان: Fatemeh Ardestani,Ali Shokuhi Rad
- مشاهده