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Lovastatin is a potent agent for lowering cholesterol of blood. Since one of the main reasons of mortality in developing countries is cardiovascular disease, which is caused by precipitation of fatty acid (especially cholesterol) in blood vessels; therefore diets containing lovastatin may prevent this type of disease. In this study, Lovastatin, monacolin K or competitive inhibitor of the HMG-CoA reductase (operative enzyme for cholesterol synthesis) was produced by submerged fermentation using Monascus purpureus PTCC5303. Seven chemical and nutritional parameters including maltose, peptone, MgSO4.7H2O, MnSO4.H2O, KH2PO4, thiamin and pH screened using Plackett Burman experimental design for monacolin production. Among different parameters, maltose and MgSO4.7H2O showed significant effect on biomass and monacolin production. The concentration of these agents were optimized using response surface methodology for lovastatin production in the shaker flask. The optimized medium contained 26 g/L maltose, 5 g/L peptone, 0.1 g/L MgSO4.7H2O, MnSO4.H2O 0.5 g/L, 4 g/L KH2PO4, Vitamin B1 0.1 g/L and pH 7. After 10 days of fermentation in the shaker flask with 130 rpm agitation and 30 ºC, we achieved maximum lovastatin production which was 63 mg/l.

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In this research, the culture condition improvement on phytase productionby Aspergillus ficuum PTCC 5288 was investigated using submergedfermentation method in 250 ml shake flask. Four factors which influencing phytase production, including carbon source (glucose) in five level (2, 3.5, 5, 6.5 and 8 g/100 mL), nitrogen source (ammonium sulphate) five levels (1, 2, 3, 4 and 5 g/100 mL), phosphor source (wheat bran) five levels (1, 2, 3, 4 and 5 g/100 mL),and fermentation time five levels (48, 120, 192, 264 and 336 hour) were studied. The optimum levels of these significant factors were determined via response surface methodological approach as: 5.23g/100 mL glucose, 1.6 g/100 mL ammonium sulphate, 3.28 g/100 mL glucose wheat branand198.30 hours.The maximum predicted amount of phytase was 39.61 U/mL and the produced amount of phytase under these conditions was 40.21 U/mL, which indicates the efficacy of the model for prediction of phytase production content under different conditions of the medium.  

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  Phytases (myo-inositol 1,2,3,4,5,6 hexakis phospho-hydrolase), found in plants, animal tissues and microorganisms, are a group of phosphatases capable of hydrolyzing phytic acid, the most abundant inositiol phosphate in nature, to myo-inositol and inorganic phosphates. In this study, 68 microbial isolates from different sources were screened using submerged fermentation for the best phytase production. The results showed that isolate K46b had the highest phytase production (1.952 U/mL) among other isolates. Subsequently, the catalytic activity of phytase enzyme of isolate K46b at different conditions of temperature, pH and sodium phytate concentration was optimized using response surface methodology (RSM). Under optimum conditions i.e. 56.5 ºC, pH 7.30 and 2.05 mM sodium phytate, the phytase activity increased to 4.627 U/mL which compared to the screening step, it showed a 137% increase. Moreover, the phytase showed 60-73% of its optimum activity in wide ranges of temperature (47-68 ºC), pH (6.3-8.0) and sodium phytate (1.04-2.50 mM). It can be concluded that isolate K46b phytase has potential applications in dephytinization of food ingredients such as cereals and meals in in food and animal feed industries, aquaculture and combating phosphorous pollution in the environment.

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Poly-γ-glutamic acid (γ-PGA) is a beneficial, biocompatible, and biodegradable biopolymer. These properties have been led to the development of the use of this compound in various industries such as bio-medicine, biopharmaceutical, biotechnology, and tissue engineering. The limitation of the industrial development of γ-PGA is the high cost of its production. To reduce γ-PGA production costs, various strategies are used, such as culture medium optimization using inexpensive compounds, the development of efficient cultivation processes of batch and fed-batch. In this research, first, an efficient batch culture medium was developed to produce γ-PGA of Bacillus licheniformis ATCC 9945^a. Then, the γ-PGA production increased by the pulsed feeding method and its optimization. By optimal culture medium development, the production of this product in batch culture was increased from 11 g/L to 47 g/L. Then, using the optimized pulsed feeding strategy of citrate (γ-PGA precursor), γ-PGA production was increased to 59.5 g/L, which is one of the highest production values reported with this strain. To optimize two-pulse feeding, the effect of feeding times, stock citrate solution concentration, and time of calcium and manganese solutions addition on γ-PGA production were investigated and optimized. Finally, FTIR confirmed the chemical structure of poly gamma glutamic acid, and the study of γ-PGA morphological properties with SEM showed a nanostructure ideal for biological applications.

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Spirulina platensis has attracted special attention in various industries due to its natural pigments with specific performance characteristics. In this study, the effects of vitamin B₁₂ (0.5 to 1.5 µg/l), date waste extract as a carbon source (1 to 1.5 g/l of glucose), and urea as a source of nitrogen (50 to 150 mg / l) parameters by fed-batch feeding under submerged culture was optimized and the production of Spirulina platensis and natural pigments were examined. The results showed that the addition of urea and date waste extract increased the production of biomass and phycocyanin, allophycocyanin, carotenoids, and chlorophyll. The results of the effect of vitamin B₁₂ showed that this vitamin in low concentration has a positive effect on the production of spirulina and the pigments phycocyanin, allophycocyanin, carotenoids, and chlorophyll. Also, the use of date waste extract with vitamin B12 should be used optimally in combination with each other to achieve the highest production efficiency of biomass and pigments phycocyanin, allophycocyanin, carotenoids, and chlorophyll. At low concentrations of vitamin B₁₂, increasing changes in date waste increase carotenoid production. Also, in low concentrations of date waste, with increasing changes in vitamin B₁₂, carotenoid production increases, but in the highest concentration of these two variables, carotenoid production decreases due to the opposite effect. In high concentrations of vitamin B₁₂, increasing changes in urea increase chlorophyll production. At the optimized condition, (vitamin B₁₂ 0.5 µg.l^-1, date waste extract 1.5 g.l^-1 of glucose, urea 150 mg.l^-1) the biomass, phycocyanin, allophycocyanin, carotenoids and chlorophyll contents were 203 (g/100g) 128, 8.42,  4.09 and 7.2  (mg.l^-1). It can be concluded that vitamin B₁₂ along with the use of date waste creates mixotrophic conditions in the growth of Spirulina platensis, which leads to increased production of biomass and natural pigments.