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Lopez, J. L., Sanchez Perez, J. A., Fernandez Sevilla, J. M., Acien Fernandez, F. G., Molina Grima, E., Em Chisti, Y.: Fermentation optimization for the production by Aspergillus terreus : Use of response surface methodology. J. Chem. Technol

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Acta Microbiologica et Immunologica Hungarica
Authors: Zsuzsa Szigeti, Szilvia Szaniszló, Erika Fazekas, Gyöngyi Gyémánt, Judit Szabon, Károly Antal, Tamás Emri, József Balla, György Balla, László Csernoch, and István Pócsi

Iron is an essential element for all microorganisms. Bacteria and fungi produce versatile siderophores for binding and storing this essential transition metal when its availability is limited in the environment. The aim of the study was to optimize the fermentation medium of Aspergillus fumigatus for siderophore production. Triacetyl-fusarinine C and ferricrocin yields were dependent on glucose and glycine supplementations as well as the initial pH of the culture media. The optimal fermentation medium for triacetylfusarinine C production contained 8% glucose, 0.4% glycine and the initial pH was set to 5.9. Meanwhile, maximal ferricrocin yields were recorded in the presence of 10% glucose, 0.5% glycine and at an initial pH of 7.4. Under optimized fermentation conditions, the yields for triacetylfusarinine C and ferricrocin increased up to 2.9 g/l culture medium and 18.9 mg/g mycelium, respectively.

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. Table I Variables and levels in response surface methodology, i.e., central composite design

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Ten different strains of Thermomyces lanuginosus , isolated from composting soils were found to produce phytase when grown on PSM medium. The wild type strain CM was found to produce maximum amount of phytase (4.33 units/g DW substrate). Culturing T. lanuginosus strain CM on medium containing wheat bran and optimizing other culture conditions (carbon source, media type, nitrogen source, level of nitrogen, temperature, pH, inoculum age, inoculum level and moisture), increased the phytase yield to 13.26 units/g substrate. This culture was further subjected to UV mutagenesis for developing phytase hyperproducing mutants. The mutant (TL-7) showed 2.29-fold increase in phytase activity as compared to the parental strain. Employing Box-Behnken factor factorial design of response surface methodology resulted in optimized phytase production (32.19 units/g of substrate) by mutant TL-7. A simple two-step purification (40.75-folds) of phytase from mutant TL-7 was achieved by anion exchange and gel filtration chromatography. The purified phytase (∼54 kDa) was characterized to be optimally active at pH 5.0 and temperature 70 °C, though the enzyme showed ∼70% activity over a wide pH and temperature range (2.0–10.0 and 30–90 °C, respectively). The phytase showed broad substrate specificity with activity against sodium phytate, ADP and riboflavin phosphate. The phytase from T. lanuginosus was thermoacidstable as it showed up to 70% residual activity after exposure to 70 °C at pH 3.0 for 120 min. The enzyme showed K m 4.55 μM and V max 0.833 μM/min/mg against sodium phytate as substrate.

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. Kim , H. M. , Kim , J. G. , Cho , J. D. , Hong , J. W. : Optimization and characterization of UV-curable adhesives for optical communications by response surface methodology . Polym Test 22 , 899 – 906 ( 2003 ). 25

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Lee, W. C., Yusof, S., Hamid, N. S. A., Baharin, B. S.: Optimizing conditions for enzymatic clarification of banana juice using response surface methodology (RSM). J Food Eng 73 , 55–63 (2005). Baharin B

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. Application of response surface methodology to improve carotene production from synthetic medium by Blakeslea trispora in submerged fermentation J. Food Bioprocess. Technol. 2010

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19 25 Palaniyappan, M., Vijayagopal, V., Viswanathan, R., Viruthagiri, T.: Statistical optimization of substrate, carbon and nitrogen source by response surface methodology or

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Acta Microbiologica et Immunologica Hungarica
Authors: Tamás Gáll, Gábor Lehoczki, Gyöngyi Gyémánt, Tamás Emri, Zsuzsa M. Szigeti, György Balla, József Balla, and István Pócsi

/ z : 1,157 Da, and m / z : 1,319 Da, respectively. Response surface methodology (RSM) The optimal medium composition for DFO-E production was determined using the RSM with two selected variables (Na- L -Glu and L

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