Showing 3 results for Etemadifar
F.s. Ghoreishi, Z. Etemadifar ,
Volume 9, Issue 1 (Winter 2018)
Abstract
Aims: Heavy metals are one of the most important pollutants in earth and water environments due to long-term durability. The aim of this study was to isolate phosphate solubilizing bacteria from metal waste, investigate the amount of resistance, remove the metal by it and the effect of phosphatase on removal of metals.
Materials & Methods: In this experimental study, the isolation of phosphate solubilizing bacteria and detection of isolates were carried out, using biochemical and molecular tests. The phosphatase was measured by colorimetric method, the resistance of the separated to the metals with the minimum inhibitory concentration (MIC50), minimum bactericidal concentration (MBC) and the rate of removal of metals by atomic absorption was measured. The surface changes of the exposed metal cells were investigated by Fourier Transform Infrared Spectroscopy (FTIR) and the effect of phosphatase on metal removal. Data analysis was done with Duncan's test, using Excel 2013 and SPSS 20 software.
Findings: Serratia proteamaculans was identified as producer of the acid phosphatase. The highest MIC and MBC were obtained for Nickel (Ni) and Lead (Pb), respectively. The most metal removal was for Pb. MIC50 of Chrome and Cadmium were obtained less than 0.1mM and 1mM, and their removal percentage by the isolate were 18% and 48%, respectively. According to the FTIR, 988.339cm-1 wavelength was observed in the cells treated by 5mM Pb that is related to the Pb3(PO4)2. The isolate showed the highest resistance and removal of Pb. The mechanism of Ni removal was associated to the cell surface, while Pb was removed by both of the cells and supernatant containing phosphatase.
Conclusion: Serratia proteamaculans is the phosphate solubilizing bacterium in metal waste. This bacterium produces an enzyme called phosphatase, which is a cause of lead removal.
M.s. Borhani , Z. Etemadifar , G. Emtiazi , E. Jorjani ,
Volume 9, Issue 4 (Fall 2018)
Abstract
Aims: Alkaline protease is one of the most important groups of industrial enzymes with many applications. The aim of this study was to determine the physicochemical parameters affecting the production of alkaline protease enzyme produced by Bacillus pseudofirmus MSB22 by one-factor-at-a-time (OFAT) method and optimize the production of this enzyme by the response surface methodology (RSM) in the form of a rotatable central composite design.
Materials and Methods: In the present experimental study, the isolation of microorganism producing alkaline protease from wastewater from sausage and lunch meat factories in Isfahan was carried out. The morphological and biochemical characteristics of the strain were performed according to the Bergey's book and amplification of 16S rRNA gene sequences. Detection of metalloproteinase gene and alkaline serine protease was done by polymerase chain reaction (PCR) reaction and enzyme activity measurement was performed by Folin reagent. Screening of variables effective in enzyme production was done, using one-factor-at-a-time method and optimization was performed by response surface methodology. MEGA 6 software was used for phylogenetic analyses. To analyze the data, the Design Expert 7 software and the one-way analysis of variance were used.
Findings: The maximum protease production, which was 1.85 times higher than that of OFAT method and 3.45 times higher than unoptimized conditions was obtained, using 1% w/v xylose, 3% w/v beef extract, 4% v/v inoculation size, pH 10, and 30°C. The established quadratic model had a great ability to predict responses to new observations due to a high value of the predicted determination coefficient.
Conclusion: OFAT and RSM strategies are useful screening and optimization methods, respectively and sub I and sub II genes (alkaline serine protease genes) are detected in Bacillus pseudofirmus MSB22.
Atefeh Salehi Bakhtiari, Zahra Etemadifar, Matia Sadat Borhani,
Volume 12, Issue 2 (1-2022)
Abstract
Background: Carotenoids are biological antioxidants and play important roles in protecting the body from diseases and aging. Canthaxanthin is one of the most widely used carotenoids in the industry and medicine. This study aimed to investigate the biological properties of canthaxanthin pigment as well as its production optimization in a low-cost medium using a radioresistant microbial strain named Dietzia maris.
Materials and methods: Bacterial carotenoids were extracted and its antibacterial, anti-tumor, and cytotoxicity properties were investigated. Then, the effect of Krebs intermediates and pH on the production of pigment and microbial biomass in the whey medium was investigated using the response surface methodology.
Results: Maximum pigment production was found to be 92/54 mg/l in whey culture medium at pH 8 and in the presence of 12.5 mM of each of citrate, glutamate, malate, and succinate by the response surface method. The pigment did not show any cytotoxic effect on Hela, HFB, and MCF-7 cell lines. Besides, the pigment did not have any antibacterial properties.
Conclusion: Radioresistant microbial strains are better candidates for microbial pigment production due to their stability and high antioxidant activity. In this study, a whey culture medium was used to reduce the production cost of canthaxanthin. The addition of Krebs intermediaries in the fermentation medium increased the pigment production by Dietzia maris significantly.
