جستجوی مقالات مرتبط با کلیدواژه "بیوراکتور" در نشریات گروه "زیست شناسی"

The process of diphtheria toxoid production was designed by using SuperPro Designer and the effect of the applied changes in process on the yield and costs of the manufacturing was investigated. First, giving the information of the real process of the toxoid production, a bioreactor with improved operational conditions and a disc stack centrifuge instead of the filter press, which is applied for the bacterial debris separation, were utilized. Such alterations followed the addition of a pump between the bioreactor and centrifuge. The results indicated that improvement of the bioreactor operational conditions can lead to the 25% increase in the toxin production, i.e., the increase of toxoid production from 7,000,000 doses to 8,750,000 doses. The toxin waste through filter press (14%) may be remarkably reduced by using the centrifuge, which in turn resulted in the 44% enhancement in the toxoid production. Such alterations can result in the 16% reduction in the separation operation time, 29% reduction in water consumption and 32% increase in the energy consumption. Overall, the simulation results showed that the costs of the new equipment suggested to be used in the improved process can be recoverable through running two batches.

In this study, the wheat germ was fermented with industrial bakery yeast powder to produce FWGE with high 2,6-DMBQ content in a Bench-scale bioreactor by scale-up approach. The 2,6-DMBQ content of FWGE was increased by optimizing the three initial variables of pH, fermentation temperature, and agitation rate at two levels using the Taguchi method. The 2,6-DMBQ content of the samples was determined at 14, 16, and 18 hours of the fermentation process. Then, the results were analyzed by Qualitek software. The effect of centrifugation speed on turbidity and the yeast's number in the final supernatant was then investigated. Finally, the supernatant was dried by spray dryer with an inlet temperature of 120 °C and outlet temperature of 70°C, and the amount of active 2,6-DMBQ, pH, moisture, and ash was determined. Under optimal conditions: initial pH of 6, fermentation temperature of 32 °C, and agitation rate of 80 rpm, maximum 1.527 mg of 2,6-DMBQ per gram of FWGE obtained. The separation results showed that the centrifugation rate doesn't have a significant effect on the final turbidity and the number of yeasts left, and thus 3000 g was selected as the optimal speed. However, because of the high content of yeast in the supernatant, filtration was required after centrifugation. Due to the high speed of sample drying, the low moisture of the final product, and high efficiency on an industrial scale, the samples were dried using a spray dryer. Finally, the moisture, protein, ash, and pH of the final product were measured.

Nitrate is one of the inorganic anions derived from the oxidation of elemental nitrogen. Nitrate contamination of groundwater and surface water has become a critical problem. Therefore, achieving the new technologies for nitrate removal is necessary. The aim of this study was to investigate the molecular mechanism of bio denitrification by thiobacillus denitrificans in the presence of quantum dot metal-carbon nanoparticles (CQD-Fe0) in a bioreactor.

Fe0 nanoparticles were synthesized by the liquid-phase reduction method, also called the borohydride reduction method and for biocompatibility, uniform distribution, and non agglomeration, Fe0 was coated with carbon quantum-dot. Characterization of nanoparticles was determined by XRD, TEM, FESEM, and FTIR. The biological process of nitrate removal was investigated in the presence and absence of nanoparticles. The expression of nirS, narH and recA genes was also assessed using real-time PCR.

The FTIR spectrum confirmed the formation of CQD-Fe0 bonds. The average diameter of CQD-Fe0 nanoparticles was in the range of 29.31 to 38.32 nm. Denitrification in the presence of CQD-Fe0, with increasing temperature (35C°) was 73.43%. In discontinuous conditions, bio denitrification was obtained for CQD-Fe0 nanoparticles 79.8312%. In the bioreactor, biodenitrification, in the presence of CQD-Fe0 nanoparticles, 95% was obtained. Examination of gene expression showed that the expression of all three genes nirS, narH and recA in cells treated with nanoparticles significantly increased compared to the control group, which indicates the high impact of these nanoparticles on the bio denitrification of this microorganism. 

Therefore, with further experiments, it is hoped that removing nitrate with Nanoparticles Zero Iron (nZVI) from water resources would be possible.

 The problem of water pollution is a fundamental and influential issue for the healthy life of humans and bioorganisms. The aim of this study is to optimize aluminum and calcium-based graphene nanostructures by response surface methodology (RSM) in order to investigate their role in biodenitrification. The optimized removal conditions in the bioreactor were investigated.

 Characterization of graphene oxide/aluminum (rGO/Al) and graphene oxide/calcium (rGO/Ca) nanostructures was determined by XRD, SEM and FTIR. The two effective operating parameters of temperature (°C) and concentration (g/L) of rGO/Al and rGO/Ca nanostructures in biodenitrification of Thiobacillus denitrificans microorganism in the presence of nanostructures were optimized by RSM. Chromotropic Acid method was used to measure nitrate.

 The FTIR spectrum confirmed the interaction between RGO-aluminum and rGO/Ca. By SEM analysis, the average diameters of rGO/Al and rGO/Ca nanostructures were observed in the range of 10.24-39.21 nm and 20.86-34.29 nm, respectively. In the presence of rGO/Ca and rGO/Al, with increasing temperature (35°C) and increasing nanostructured concentration (1g/L), removal was achieved for 74.0985% and 77.6905%, respectively. After determining the optimized conditions, the biodenitrification of the microorganism in the presence of nanostructures was investigated in the bioreactor. According to the results, the microorganisms in the presence of rGO/Ca and rGO/Al nanostructures had 74.0985% and 77.6905% biodenitrification, respectively.

 The percentage of biodegradation in the presence of rGO/Al was higher than rGO/Ca and in the presence of rGO/Al was 98%, so this nanostructure in the bioreactor showed higher efficiency in nitrate removal.

Glucose oxidase (GOX) is considered a commercial enzyme in the medicine, pharmaceutical, and food industries. Optimization of the fermentation medium and conditions is important to increase heterologous GOX production. The current study aimed to optimize GOX production in a ‎recombinant strain of Yarrowia lipolytica via statistical techniques.

Response surface methodology (RSM) as a statistical technique for the design of the experiment was used for the optimization of recombinant GOX production by Y. lipolytica. Then, the optimized conditions were used for the production of GOX in bioreactor cultivation.

GOX production was increased up to 570 U/L after optimization of the medium in flask culture which is 2 times more than the non-optimized medium. In the bioreactor culture using optimized medium containing glucose and sucrose as carbon sources, GOX production was reached 720 and 730 U/L after two and six days, respectively.

Results of the study provided valuable information about the statistical optimization of bioprocess development for the production of heterologous protein in Y. lipolytica.

Biosurfactants are metabolites produced by microorganisms which have potential capabilities in various industries due to abundant beneficial properties. In spite of great advantages, commercial utilization of biosurfactants especially in food industry and pharmaceuticals are limited for the reasons of technical and commercial such as low yield, high production cost, and the type of producing strain. Majority of biosurfactant producer microorganisms have ever evaluated, are pathogenic strains which are not acceptable in industrial and environmental utilization particularly in health and cosmetics, pharmaceuticals and food industries. However, the present study aims to investigate high production of cell-bound biosurfactant by lactic acid bacterium Lactobacillus plantarum through optimization of the main carbon source of specific culture medium. Therefore, three culture media with different amount of glucose were evaluated for biomass and biosurfactant (by surface tension reduction of phosphate buffered saline) production in shake flasks and bioreactor (controlled temperature, pH and agitating speed). The results from both shake flasks fermentation and bioreactor showed the maximum biomass concentration of 3.9 and 4.17 g/L, the minimum surface tension of 41.17 and 40.48 mN/m and subsequently the maximum biosurfactant production in culture medium including 30 g/L of glucose, respectively. Furthermore, fourier transform infrared spectroscopy analysis indicated the biosurfactants are structurally a mixture of protein, polysaccharide and possibly phosphate group, possessing glycoprotein structure.

Nerve growth factor (β-NGF) is an important therapeutic agent for the treatment of neurodegenerative diseases such as Alzheimer’s disease; so, recombinant production of it in industrial scale is of high importance. The aim of this study is to optimize the effective factors in achieving the highest rate of β-NGF protein production in the bioreactor. As E. coli is a suitable host for industrial production of recombinant proteins, E. coli DE3 strain was used for production of recombinant β-NGF. Also, fermentation was performed in a 5-L bioreactor and % dissolved oxygen (%DO) and post-induction temperature values were optimized by response surface methodology (RSM). At first, the effects of these two variables on the level of total protein were studied. So, in every experiment, bacterial proteins were isolated and total protein concentration was determined by Bradford assay. The results indicated that %DO and post-induction temperature of 30% and 28.5ºC were the best values for increased production of total protein; in these circumstances, total protein concentration was 9.6±0.61 mg/ml. Finally, the effects of these variables on recombinant β-NGF production were surveyed by dot blot analysis, indicating the maximum β-NGF expression level on the optimized condition. In conclusion, %DO and post-induction temperature not only affect cell growth of recombinant E. coli, but also have a direct impact on recombinant protein expression and production, such as β-NGF.

Engineered plants as bioreactors for production of heterologous proteins are appropriate replacement for conventional expression systems such as mammalian cell culture and transgenic animals. For efficient production of recombinant proteins, the type of host species is very important and its choice depends on the type of recombinant proteins, plant life cycle and its performance, and maintenance or production costs. The most important benefits of plant-based expression systems could be included: cost effective of the plant systems, no contamination of recombinant proteins derived from plants with human pathogenic microorganisms due to host-less of plants to human pathogens, easy and low cost of extraction and purification of proteins, more post-translational changes required for the stability and activity of protein by plants. For development of plant-based production of recombinant proteins, optimization of protein expression level is essential. In this regard; various factors controlling the expression of target gene at levels of transcription, translation, post-translational modifications and recombinant protein accumulation are involved. On the other hand, lower amounts of expressed recombinant proteins are serious problem limiting commercial exploitation of plants bioreactors. Thus improving the accumulation of recombinant proteins in transgenic plants is an important factor in the desirability of an expression system. In this regard, the accession of signals in C-terminal of target proteins leads to increased retention and accumulation of proteins in the endoplasmic reticulum. After production of recombinant proteins, the use of affinity tag for purification of proteins are very effective and useful, so protein purification will possible without prior notification of their biochemical properties.

Nisin is the first FDA-approved food preservative produced by Lactococcus lactis at industrial scale. The negative effect of lactic acid produced by metabolism of Lactococcus lactis subsp. lactis, on nisin production, was removed by co-culture of Lactococcus lactis with Yarrowia lipolytica yeast. In the present study, the co-culture of Lactococcus lactis subsp. lactis and Yarrowia lipolyticawas performed for the first time inmolasses-based medium at 30°C, pH 6, 100 rpm, 0.15 vvm was applied in a laboratory scale bioreactor. Nisin production was measured as 920 IU/mL. The results showed that co-culture fermentation increased biomass and nisin production up to 63% and 78%, respectively. Other factors such as extracellular proteolytic activity of the yeast should be taken into consideration, which in turn make the culture nutrients more available to the bacterium.

Special properties and various applications of Spirulina species have led to the growing focus of biotechnology to the cost effective cultivation. Open ponds used in the most commercial cultivation have many deficiencies such as risk of contamination, lack of light penetration, inefficient mixing and low productivity. In this study, an innovative reactor was designed and manufactured. By adding a control area, it was possible to control some environmental conditions for a limited amount of open pond volume. The conventional pumping system was replaced by a new elevator system to reduce the damage of to the fragile cells. The baffles structure and aeration from bottom, contributed to better mixing system. The effect of tree factors (Circulation Cycle (Cir. Cyc.), Control Volume (Con.Vol.) and Irradiance Intensity (Irr. Int.) in units of hours, percentage and Lux respectively) on the quantity of biomass (Specific Growth Rate (SGR, day-1) and fifth and seventh day dry weight (g/L)) were evaluated using RSM-CCD. The maximum biomass dry weight (0.915 g/L) was achieved in longest circulation cycle (12 hours), 30% Con. Vol. and 7000 Lux light intensity. The optimal irradiance intensity to achieve the highest biomass was 8700 Lux. According to the results, due to the great influence of Con. Vol. and Cir. Cyc., it is possible to increase the productivity and enhance the culture dry weight by controlling a limited amount of ponds volume (20%), subject to economic considerations. These successful results can provide the context using a control zone for several open ponds to improve the overall efficiency.

Biopolymers are biological macromolecules that large and small subunits that bind covalently to the same are connected by a long chain of cause and they are built. Because of the biopolymers are produced naturally of the living organisms such as plants, animals and microorganisms therefor are biodegradable, they are very good. biopolymers have been developed in various forms, therefor have capacity to use in various industries. In order to use biopolymers in industry to commercialization the production process and optimize its production. Regard to the main role a well bioreactor, providing a controlled environment in order to achieve optimal conditions for growth or production type of Bioreactor also affects the production of biopolymers. In this study, an overview of the biopolymers and various bioreactor and have been investigated suitable bioreactor for the production of microbial biopolymers.