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Backgrounds:  Celiac disease (CD) is a common autoimmune disorder caused by intolerance to gliadin protein found in wheat, rye, and barley, which is prevalent among 1% of people in different parts of the world. Thus, in the last decades, the demand for gluten-free products has increased. The aim of the present study was to demonstrate the degradation of wheat gluten in laboratory.
Materials & Methods: Yeast colonies obtained from cloning were assessed for the presence of Saccharomyces cerevisiae with protease activity and then inoculated onto MSM (mineral salts medium) with 1% (w/v) gliadin. Aspergillus niger-derived prolyl endoprotease (AN- PEP ) production was also qualitatively examined on gliadin agar plates by determining yeast colony growth.  Zones of clarification of gliadin around yeast colonies were regarded as the evidence of glutenase activity of AN- PEP . The qualitative effects of aspergillopepsin expressed in bakery yeast were studied on yeast gliadin and the rheological properties of wheat flour dough. The rheological properties of the dough were investigated by a rheometer.
Findings:  In this survey, gluten was efficiently degraded into short fragments by the AN-PEP enzyme. The results of rheometer test showed that the use of AN-PEP could affect the rheological properties. The quality of dough and the ability of AN-PEP to degrade gluten in dough into smaller fragments were confirmed.
Conclusion:  The current study gives evidence that in the future, the development of novel gluten-free products with high quality and taste is possible by degrading gluten protein into non-toxic peptides using a variety of AN-PEP enzymes.
 

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The Stability of protease in organic solvent media has been widely discussed for more than two decades. Proteases can catalyze synthetic reactions in organic media, by this way solvent stabilities of proteases are very important. In this study, we reported a bacterium isolated from hot spring of Geinarje, Iran producing an organic solvent stable protease. Protease producing bacteria were screened on skim milk agar and the formation of a clear zone around the bacterial colony was investigated. Proteolytic activity was assayed by a modified caseinolytic method using casein as a substrate. The best alkaline protease producing bacterium was selected and identified on the basis of 16S rDNA gene sequencing and morphological and biochemical characteristics. The effect of organic solvents, temperature, pH, and NaCl on proteolytic activity were examined. According to phylogenetic analysis, morphological and physiological tests, isolated, the bacterium was identified as a new strain of Brevibacillus borstelensis. This strain was able to produce an extracellular organic solvent-stable protease with 0.53U/ml enzyme activity. After 2 hour incubation at 30°C the protease of Brevibacillus borstelensis AMN was active in wide ranges of organic solvents, and its activity was enhanced in the presence of 25% (V/V) isopropanol. The biochemical properties of the enzyme revealed that the optimal pH and temperature for protease activity were 9.0 and 60°C, respectively. Our finding indicated that these robust properties of protease, like outstanding activity and stability in organic solvents and alkaline medium, might be applicable for various industrial biotechnologies.
 

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Although biosurfactants have great advantages over chemical surfactants, their wider industrial applications have been constrained by their relatively high production cost. Using renewable, sustainable and cheap substrates such as different industrial by-products and wastes maybe decrease biosurfactant production costs. Since in different countries, there are a variety of by-products and wastes so use of these substrates rely on their types and concentrations in countries. In addition to hydrocarbon compounds, molasses has been considered as a dominant by-product in Iran. In this study, among 16 crude oil degrading isolates, strain Pseudomonas aeruginosa ZN was selected as an efficient biosurfactant producer by screening methods for detection of biosurfactant producing bacteria. For investigation of molasses concentrations effect on bacterial growth and biosurfactant production, a wide range of molasses concentrations from 2-12% (v/v) were used. This strain was able to grow and produce biosurfactant in all range of molasses concentrations while the best concentrations were 4-6%. Also, at the optimum molasses concentration, reduction of surface tension from 70 to 32-34 mN/m was observed. The concnetrations more than these values decreased the growth and production process. Acid precipitation and solvent extract (ethyl acetate: hexane) methods were carried out for recovery of biosurfactant from the culture broth, then results of spraying on developed TLC and staining fermentation broth without bacterial cells showed the two produced biosurfactants were glycolipid.