مقالات رزومه فاطمه تابنده

Hyaluronic acid (HA) is a natural and linear polymer that finds a wide-range of applications in medicine, cosmetics, and nutraceuticals because of excellent viscoelasticity, high moisture retention capacity, high biocompatibility and non-toxicity. HA has been recently produced in industrial scale by Streptococcal species. Streptococci are nutritionally fastidious lactic acid bacteria and cannot synthesize some amino acids. Therefore, it is necessary to study and select some commercial culture media for their growth. In this study, HA production and hyaluronidase activity of S. zooepidemicus ATCC 43079 in three culture media were investigated. Regarding the detrimental effect of this enzyme on HA amount, 6-O-Palmitoyl-L-ascorbic acid as hyaluronidase inhibitor was added to culture medium during fermentation. The effect of three variables consisted of glucose concentration, yeast extract concentration and medium pH each at 3 levels were considered and (response surface methodology (RSM) was used for statistical design of experiments to study the HA production by this strain. The results showed that maximum HA production was obtained when glucose concentration, yeast extract concentration and pH were 21.2 g L-1, 43.6 g L-1 and 6.6, respectively. Under optimum conditions, HA was produced as 370±15 mg L-1 which was ~150% more than of HA concentration in basal medium (150±10 mg L-1) and productivity reached 56.74 g L-1 h-1 that was increased 2 fold compared to central point.

In order to targeted delivery of probiotics for food and drug applications and their effectiveness in preventing and treating various diseases, designing effective systems in this field can be helpful. In this paper, a new system for targeted delivery of probiotics has been introduced. The objectives of this study included: the efficiency of anti-acid microgels coated by multilayer polyelectrolyte formulation of alginate-chitosan for survivability of probiotic bacteria in gastric and intestinal simulation conditions. Tow Strains of probiotic bacteria including Lactobacillus Rhamnosus and Lactobacillus Plantarum were encapsulated separately in alginate hydrogels and calcium carbonate as an antacid agent (to control pH under acidic conditions) and coated with double bilayer alginate-chitosan by LbL self-assembly technique. The results showed that ( in the presence of pepsin enzyme and at pH=1.8 and in the presence of pancreatin enzyme and at pH=6.8), the survivability of these bacteria increased significantly compared to lactobacillus Plantarum and Lactobacillus rhamnosus 6 log(cfu/g) and 2.5 log(cfu/g) respectively. The number of viable cells in both probiotic strains was higher than the acceptable therapeutic level. In general, these results showed that these microcapsules can be used in controlled delivery of probiotics as food supplements successfully.

Hyaluronic acid (HA) is a major component of the extracellular epithelial, neural and connective tissue of vertebrates, as well as of extracellular microorganisms. This polysaccharide has specific applications in ophthalmology, orthopedic, cosmetics and tissue engineering due to features such as high viscosity and biocompatibility. Animal tissues and streptococci have a major role in producing hyaluronic acid, but because of problems such as protein contamination and the presence of endotoxin, attention has been drawn to the GRAS bacteria for producing hyaluronic acid. Lactobacilli are probiotic bacteria that have diverse uses. The production of biochemical macromolecules by this group of bacteria is a priority because they are GRAS. Hyaluronic acid production for the first time in these GRAS bacteria including Lactobacillus acidophilus PTCC1643, Lactobacillus rhamnosus PTCC1637, Lactobacillus casei PTCC1608 and Streptococcus thermophilus PTCC1738 were investigated. In the first step, Hyaluronic acid was isolated from specific culture medium and partially purified by ethanol precipitation daily for 96 hours. Carbazole method was used to measure the production of hyaluronic acid. Based on results, Lactobacillus rhamnosus produced about 0.4 g/l of hyaluronic acid at 96 hours. The increase of HA was also investigated using optimization culture medium by Taguchi design. By using this method, the optimum points of the factors were determined and the hyaluronic acid production increased by 162%.

Age-Related Macular Degeneration (AMD) is one of the biggest causes of vision loss after 50 years of age in the world. AMD disease destroys the retinal pigment cells. Retinal tissue engineering provides a suitable environment for the growth of retinal pigment epithelium cells using different scaffolds. These scaffolds may cause interior pressure changes in eyes and thus, causes disease of the separation of pigment and retinal epithelial cells. Therefore, the purpose of this study was to simulate gelatin, gelatin-chitosan and poly-caprolactone scaffolds in the retina and compare the pressure gradient and the effect of thickness on the pressure gradient. In the present experimental study, in the first stage, three gelatin, gelatin-chitosan and poly-caprolactone scaffolds were simulated to examine the average scaffold pressure using COMSOL 5.1.1 software and Darcy law. In the next step, a gelatin-chitosan scaffold with thicknesses of 10 and 20 micron was simulated with Darcy law, to examine the effect of thickness on average pressure. The output pressure of the gelatin scaffold was calculated as 308.800Pa Which was less than the pressure level of the caroid layer And it was less than the output pressure of other scaffolds. The average pressure of gelatin-chitosan scaffold with thicknesses of 10 and 20 micron was 1997.31 and 2003.13 respectively in the last step. The gelatin scaffold produces a moderate lower pressure than the gelatin-chitosan scaffold and poly-caprolactone in the retina and it is more suitable than other scaffolds. In the simulation of gelatin-chitosan scaffold, increasing the thickness causes increased pressure and retinal impairment.

The white rot fungi can produce different isoenzymes of extracellular oxidases such as lignin peroxidase, manganese peroxidase and laccase having ability to decompose lignin. Because of the non-specific nature of peroxidases produced by lignin-degrading system of white rot fungi, they can be used for degradation of a wide range of toxic and carcinogenic materials including industrial dyes. Laboratory studies on the ability and physiology of lignolytic system of white rot fungi demonstrated that it is promising to use these fungi for wastewater treatment of those companies which produce and consume industrial dyes. For large-scale treatment of wastewater containing dyes, it is necessary to immobilize these fungi on suitable carries in bioreactors. In this article, considering the metabolic and physiological characteristics of white rot fungi and their lignolytic system, the previous studies carried out on the degradation of dye wastewater using these fungi in free or immobilized form have been mentioned and their perspective has been also presented.

Aims and Amylases are one of the major industrial enzymes that occupy 25 % of the world enzyme market. These enzymes are used in many different areas، such as paper، textiles، pharmaceutical، food، starch saccharafication and processing industries. Much research has been carried out regarding application of amylolytic enzymes produced by the genus Bacillus، to the production of glucose and beverages، food and detergent industries. Because of the extensive applicability of amylolytic enzymes، research in relation to identification of these enzymes and their characteristic is continuously being carried out. Hence، the aim of this research was to investigate the amylolytic enzyme profile of a native Bacillus strain، and determine its enzyme characteristics. In this study، the enzymatic profile of the bacterium، Bacillus amyloliquefaciens BEH 111، was determined by using the SDS-PAGE، zymogram and TLC methods. Zymography and TLC were used to identify the amylolytic enzyme profile of the bacterium. The molecular weight of α-amylase was estimated by SDS-PAGE. The 3، 5-Dinitrosalisyclic acid (DNS) indicator was used to examine α-amylase activity، quantitatively. Investigation of enzyme characteristics and determination of maximal enzyme activity was carried by the DNS method، at different temperatures، pH values، substrate concentrations and time periods. The molecular weight of α-amylase was estimated to be 55 kDa by SDS-PAGE. Investigation of enzyme characteristics showed that maximum α-amylase activity was achieved at a temperature of 50oC، pH 7، presence of 2% starch، during a 90 min time period. Enzyme activity obtained under these conditions was 8222 U/L. The high level of enzyme activity produced by B. amyloliquefaciens BEH 111 can thus be of commercial significance. Furthermore، by having activity at 50oC and above، makes it possible for this enzyme to be applied to processes that use high temperatures. The optimized pH levels of 6-7 that resulted in high enzyme activity can also allow the potential use of this enzyme in processes such as starch liquefaction and gelatinization.