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The thermophilic fungus Mycothermus thermophilus is one of the most important thermophilic fungi in mushroom composting process. Thirty nine isolates of M. thermophilus were collected from nine provinces of Iran and were identified as M. thermophilus based on morphological features and ITS regions. The studied isolates significantly increased the growth of Agaricus bisporus hyphae compared to control when used in vitro situation. Also the colony morphology of the mushroom changed when it grew on the colony of M. thermophilus. While the studied thermophilic isolates were morphologically different, no diversity was observed in terms of Random Amplified Polymorphic DNA (RAPD) finger-printing. The genetically clonal population of M. thermophilus collected from Iranian mushroom composting farms was attributed to lack of sexual reproduction, similar raw materials used in compost formulations, compost temperature, and concentration of ammonia during pasteurization as selection pressures.

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Production and characterization of bacterial thermophilic avicelase Fatemeh Azadian, Arastoo Badoei-dalfard*, Abdolhamid Namaki-Shoushtari, Mehdi Hassanshahian Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran Nowadays, developing processes for effectively converting agricultural wastes for production of high value chemicals has gained considerable interest. Avicelases are important industrial enzymes for the most bioconversion processes. In this study, samples were picked up and inoculated in AVI broth for 7 days at 50 ºC. The bacterial strains with the clear halo (represent extracellular avicelase) have been purified. AV8 isolate which showed the highest clear halo was selected for further studies. This strain was identified as Bacillus genus based on biochemical tests and 16S rRNA analysis. Avicelase production was considered under varying environmental parameters. The best carbon and nitrogen sources for maximum avicelase production were 0.5% sucrose and 0.25% yeast extract, respectively. Avicelase from this strain has been partially purified using ammonium sulphate fractionation followed by dialysis and ion exchange Q-Sepharose chromatography. Results showed that enzyme was active and stable between 30-70 ºC and itʼs maximum temperature activity was observed in 70 ºC. The optimum avicelase activity and stability was observed at pH 6.0. These are characteristics indicating that this enzyme could be an acidophilic and thermophilic avicelase. Furthermore, the avicelase activity improved by methanol (138 %) and chloroform (107 %). These results indicated that AV8 avicelase has potential applications in various industries.

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The combustion of fossil fuels containing sulfur results in the release of sulfur dioxide into the atmosphere and environmental pollution. Hence, the researchers focused on the biological desulfurization method. Dibenzothiophene is used as the model molecule to study the ability of the desulfurization of microorganisms. The most suitable sources of carbon, nitrogen and sulfur concentration optimized by response surface method to obtain the highest cell growth and biological desulfurization activity. The performance of iron nanoparticles on the growth and biodesulfurization activity of thermophilic bacterium Bacillus thermoamylovorans strain EAMYO was investigated. Characterization of starch-modified iron nanoparticles was performed by TEM, SEM. The images of TEM and SEM of starch / Iron nanoparticles showed that the Fe₃O₄ and Fe0 nanoparticles were 20 and 30 nm, respectively. The investigating the growth of microorganism in the presence of iron nanoparticles showed that these nanoparticles not only did not have a toxic effect on microorganism growth, but also increased the growth of microorganism in 96 h (OD 660 = 1.864, 1.896 respectively in the presence of nanoparticles Fe₀ and Fe₃O₄), while the highest rate of growth in the absence of nanoparticles in 96 h (OD660 = 1.51). Also, the activity of desulfurization in the presence of starch/Fe₀ nanoparticles and starch/Fe₃O₄ / starch increased by 26.52% and 10.75%, respectively, compared to the cells without the coating of iron nanoparticles.
 

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The effect of a selected autochthonous starter culture made up by Streptococcus thermophilus, Lactobacillus delbrueckii subsp. lactis and Lactobacillus helveticus on the microbiological and physicochemical properties of Pecorino Romano cheese during ripening was investigated. The suitability of the experimental starter culture was tested at industrial scales in cheese-making trials of Pecorino Romano. Pecorino Romano cheese manufactured by use of scotta-fermento served as control. The lactic microflora increased significantly in experimental cheeses as compared to the control and this was also accompanied by a substantial decrease of spoilage microorganisms in experimental cheeses. Free amino acids (FAAs) were more abundant in experimental cheeses, arginine+g-aminobutyric acid and leucine in particular. These differences could be likely due to a different enzymatic activity of the selected starter culture as compared to the scotta-fermento used in the control trials. Oleic (C18:1), palmitic (C16:0), butyric (C4), stearic (C18:0) and myristic (C14:0) acids were the most abundant Free Fatty Acids (FFAs) detected in both brand of cheeses at the end of ripening. Overall, the level of FFAs in experimental and control cheeses did not show significant differences, even if the average values in experimental cheeses were always slightly higher than those recorded for the control. Moreover, the average content of FFAs of Pecorino Romano was found the lowest when compared with the other Sardinian PDO cheeses; most likely the high content of sodium chloride and the low aW of Pecorino Romano influenced all the lipase activities, even those present in the rennet paste. Despite this, the employment of the selected starter culture revealed useful to improve the physico-chemical features of Pecorino Romano while preserving its tipicity.